Final draft2

Climate-Smart Agriculture _ Training Manual Wheat Production The efficiency of herbicide absorption into quickly to resource changes and have a the plant is determined by several factors. higher likelihood of adapting and reproducing Temperature, moisture, relative humidity, in different habitats. Weeds with C3 or C4 and solar radiation are some of the factors photosynthetic pathways have different to consider. These factors have an impact responses to climate change. on a plant's physiologic state and herbicide Some examples of C3 weeds are: Wild susceptibility. Interactions between these buckwheat (Fallopia convolvulus, Figure 10 factors make determining their effects on and Figure 11), Lambsquarters (Chenopodium herbicide performance even more difficult. album, Figure 12 and Figure 13) and Wild Oats Weeds, which have more genetic diversity and (Avena fatua, Figure 14 and Figure 15). physiological plasticity than crops, respond Figure 10 Wild buckwheat seedling. Source: Hestia Nienaber. Figure 11 Wild buckwheat in an oats field. Source: Hestia Nienaber. 200

Climate-Smart Agriculture _ Training Manual Wheat Production Figure 12 Young Chenopodium plant. Source: Hestia Nienaber. Figure 13 Chenopodium seeds. Source: Hestia Nienaber. Figure 14 Avena plant. Source: Hestia Nienaber. 201

Climate-Smart Agriculture _ Training Manual Wheat Production Figure 15 Avena spikelets. Source: Hestia Nienaber. All of the weeds mentioned above can quickly leaf thickness rises and the number of open disperse and establish themselves in new areas, stomata falls, reducing the amount of foliar- posing a threat to ecosystem composition and applied herbicide that is directly absorbed into integrity. Many weeds are expected to expand the plants and protecting weeds from post- their geographical range and cause greater crop emergence herbicide damage. productivity losses as warmer winters make higher latitudes more conducive to plant growth The uptake of herbicides applied to the and higher temperatures make lower latitudes soil is further reduced by reduced stomatal less habitable (Patterson, 1995; Parmesan and conductance (Bunce & Ziska, 2000; Ziska, 2008). Yohe, 2003). Furthermore, at high rCaOte2 sl,epvealrst,icaunlarilnycrineaCs3e in net photosynthetic AalnmionsctrecaesretaininClyO2hlaevveelas in the atmosphere will weeds, could result in rapid seedling growth. significant impact on Because the seedling stage is the most weed biology. Herbicide performance on weeds vulnerable for effective weed control, the will be affected as a result. The most noticeable timing of post-emergence herbicide application ereffdeuccttioofninicnresatsoemdaatatml ocospnhdeurcitcanCcOe2, levels is a may need to be adjusted. Lambsquarters is an which in example of a C3 weed that has demonstrated some plants can increase by up to 50%. (Bunce, increased tolerance to glyphosate as a result 1993). Reduced stomatal conductance, in turn, of increased growth and biomass at higher CO2 can affect herbicide efficacy, both foliar and levels (Ziska et al., 1999). soil-applied. Furthermore, as CO2 levels rise, 202

Climate-Smart Agriculture _ Training Manual Wheat Production 3 INTERVENTIONS ON THE IMPACT OF CLIMATE CHANGE To achieve the highest possible yield, farmers (air), and plant root support. Poor crop can use high-quality seed and planting materials production results from soil degradation, which of well-adapted varieties; a diverse range of is usually caused by soil tillage by increasing crop species and varieties grown in associations, water run-off and soil erosion, as well as intercrops, or rotations; pest control through significant losses of soil organic matter (GrainSA, integrated pest management; and conservation 2015). Improving the soil's quality is therefore agriculture and sustainable mechanization critical. to maintain healthy soils and manage water A healthy agricultural soil, shown in Figure 16, efficiently (FAO, 2011). is one that can support the production of food It's also crucial to understand the appropriate and fibre at a level and quality sufficient to meet operations to perform on a small grain field, human needs, as well as the continued delivery the appropriate time to perform them, the of other ecosystem services critical to human appropriate method to perform them, as well quality of life and biodiversity conservation as why the operations are performed, why they (Kibblewhite et al, 2008). A healthy soil is alive are performed at a specific time, and why they and provides plants with essential nutrients, are performed in a specific manner. Climate- water, oxygen (air), and root support. Healthy smart small grain production: what, when, and soil, contains many living organisms. It is deep, how. loose, full of air and water and it is easy to work on. 3.1 SOIL HEALTH A healthy soil has a good structure that creates air pockets allowing water to infiltrate and move Higher yields are difficult to achieve in soils deep into the soil. depleted of essential nutrients, water, oxygen Figure 16 Healthy loose soil with good structure versus unhealthy cloddy soil with poor structure. Source: https://www.rolawn.co.uk/soil-structure. 203

Climate-Smart Agriculture _ Training Manual Wheat Production Healthy soils act as giant moisture sponges, 3.1.1.1 Why organic matter is so important? which is critical during times of drought and Living organisms in soil help to control insect flooding. To accomplish this, the soil requires pests, weeds, and plant diseases, form beneficial a continuous supply of organic matter and symbiotic relationships with plant roots, recycle the accumulation of organic matter, and plant nutrients from soil organic matter and conservation agriculture is the solution. minerals back to roots, and improve soil Conservation agriculture increases resilience by structure. Earthworms (shown in Figure 17) are improving soil quality. an example of an organism that helps to increase 3.1.1 Organic matter the amount of air and water that enters the soil. Organic matter in the soil consists of three They convert organic matter, such as leaves and distinctly different parts: living organisms, fresh grass, into nutrients that plants can use. When residues and well decomposed residues. The they eat, they leave behind castings that are a living organisms in the organic matter includes very valuable type of fertiliser. Earthworms are a wide variety of microorganisms, such as essentially free farm workforce. bacteria, viruses, fungi, protozoa and algae. It Essentially all soil properties are positively also includes plant roots, insects, earthworms, influenced or modified by organic matter. As and larger animals such as moles and rabbits. organic matter increases, soils tend to be less The living portion represents about 15% of the compact and have more space for air passage total soil organic matter. and water storage. On the other hand, as soil organic matter declines, it becomes increasingly difficult to grow plants due to increased problems with fertility, water availability, compaction, erosion, parasites, diseases, and insects. Figure 17 Earthworms in healthy soil. Source: https://grist.org/food/feed-your-soil-and-the-rest-will-follow. 204

Climate-Smart Agriculture _ Training Manual Wheat Production To maintain yields in the face of organic matter can affect organic matter decomposition and depletion, ever higher levels of inputs, fertilisers, increase carbon dioxide emissions. In addition, irrigation water, pesticides, and machinery are additional mineral nitrogen, primarily in the required. However, with proper organic matter form of nitrate, will be released into the soil management, the soil can support a good crop system during this process. This change in soil without the need for costly fixes. environment has an impact on the stability The addition of organic matter to the soil of soil organic matter and, as a result, the soil increases the soil's water holding capacity. biological system. Because water is the primary medium for The most significant effect in cropland is the moving nutrients into plants as a result of water excessive release of nitrate, which may not uptake, more water in the soil means more be utilised by crops due to a lack of moisture nutrient uptake by crops. available for the plant to absorb nutrients. The rise in soil temperature due to deficiency of This shift in biological and chemical processes soil moisture has an effect on microbial activity during the growing season influences many and nutrient processing, both of which are other relationships that are essential for important for plant use in biomass and grain crop performance, both quantitatively and production. Soil moisture and temperature, qualitatively, by changing activities that in general, control microbial activity in soil. are important to nutrient cycling, such as Deviations from the optimum ranges of enzymatic activities, changes in soil chemical soil moisture (water field capacity) and soil concentrations, and so on. temperature, which vary for different microbial The well-decomposed organic material in the communities in soil, can alter microbial activity. soil is known as humus (see Figure 18). During a drought, changes in soil temperature Figure 18 Wheat seedlings growing on healthy soil with well decomposed humus. Source: https://regenerationinternational.org/2015/10/08/emerging-land-use-practices-rapidly-increase-soil-organic- matter. 205

Climate-Smart Agriculture _ Training Manual Wheat Production Microorganisms convert simple sugars or liquid nutrients, some farmers overload their carbon exuded from plant roots to humus. fields with excess nutrients by excess Some essential nutrients are stored in humus imports of organic materials. Crop and released slowly to plants. Humus can also residues (including cover crops) as well act as a barrier to certain potentially harmful as on-farm-derived animal manures chemicals, preventing them from harming and composts help to supply organic plants. Humus in soils has an average age of materials and cycle nutrients without a more than 1,000 years due to its stability and buildup of excessive levels of nutrients. complexity. Although the already decomposed 4. Implement practices that decrease humus is not a food source for organisms, its the loss of organic matter from soils small size and chemical properties make it an because of accelerated decomposition important component of a healthy soil. or erosion. 3.1.1.2 How to increase soil organic matter All practices that aid in the increase of organic matter levels either add more organic materials 1. Use crop residues more effectively and or reduce the rate of organic matter loss from find new sources of residues to add to soils. Furthermore, practices that increase soils. New residues can include those organic matter will usually benefit beneficial grown on the farm, such as cover crops, organisms while stressing pests (see Table or those available from various local 4). Practices that combine the two may be sources. particularly beneficial. Practices that reduce organic matter losses either slow the rate of 2. Try to use a number of different types decomposition or reduce erosion. Soil erosion of materials - crop residues, manures, must be controlled in order to keep organic composts, cover crops, leaves, etc. It matter–rich topsoil in place. In addition, organic is important to provide varied residue matter added to a soil must either match or sources to help develop and maintain a exceed the rate of loss by decomposition. These diverse group of soil organisms. additions can come from off-field manures and composts, crop residues and mulches that 3. Although use of organic materials remain following harvest, or cover crops. from off farm can be a good source for building soil organic matter and adding 206

Climate-Smart Agriculture _ Training Manual Wheat Production Table 4 Effects of different management practices on gains and losses of organic matter, beneficial organisms and pests. Management Practice Gains Losses Enhance beneficials (EB), Increase? Decrease? Stress Pests (SP) Add materials (manures, composts, other organic yes no EB, SP materials) from off the field Better utilise crop residues and mulches yes no EB Include high-residue-producing crops in rotation yes no EB, SP Include sod crops (grass/legume forages) in rotation yes yes EB, SP Grow cover crops yes yes EB, SP Reduce tillage intensity yes/no* yes Use conservation practices to reduce erosion yes/no* yes EB *Practice may increase crop yields, resulting in more residue. EB 3.1.2 Conservation agriculture 3.1.2.1 Minimum tillage Conservation agriculture (CA) aims to achieve This is when the soil is not ploughed. The goal is sustainable and profitable agriculture through to disturb the soil as little as possible. The seeds the application of the three CA principles are planted directly into the mulch covered of conserving, improving, and making more field using specialised no-till planters. The efficient use of soil, water, and biological soil is disturbed only where seed and fertility resources (plants, animals, insects, and amendments (fertiliser, manure, compost) are microbes). to be placed. The three CA principles are: 3.1.2.1.1 Advantages of minimum tillage 1. Continuous minimum mechanical soil The benefits of disturbing the soil as little as disturbance; possible are as follows: 2. Permanent organic soil cover; and 1. It ensures minimum destruction of the 3. Diversification of crop species grown in soil structure. sequences and/or associations. 2. It protects the soil from wind and water Conservation farming holds tremendous erosion. potential for farms of all sizes, but the most significant limitation is the initial lack of 3. It allows for slower mineralisation knowledge when a producer decides to switch of organic matter, resulting in the from plough-based farming to CA. accumulation of organic matter. 4. It has little impact on the life of soil organisms, which helps to improve soil structure. 207

Climate-Smart Agriculture _ Training Manual Wheat Production 5. It saves time, energy, and money 3.1.2.2.1 Advantages of mulching because there is less ploughing and 1. Properly managed mulching improves fertility amendments are only applied to planting areas. water infiltration resulting in a higher soil water content. 3.1.2.2 Mulching / Soil cover 2. It helps in reducing direct raindrop The soil remains covered with either crop impact and run-off in the field thus residue or other types of mulch like cover crop reducing soil erosion. (see Figure 19) or growing plants on the soil at 3. It reduces evaporation and conserves all times. In CA, crop residue is typically left on soil moisture. the field to cover the soil. Other types of mulch 4. It keeps soil moisture even and cool. can be used to fill in the gaps between the 5. It aids in the suppression of weeds. planting rows. Mulching reduces soil erosion 6. It provides food and a conducive and soil temperature by at least 4°C, creating environment for soil organisms, which better conditions for soil organisms to thrive. are essential for biological processes and soil fertility. Figure 19 Soil covered with cover crop between rows of wheat crop. Source: https://mail.sssup.it/~barberi/research.htm. 208

Climate-Smart Agriculture _ Training Manual Wheat Production 3.1.2.3 Crop diversification, mixed cropping All of these advantages of diversification and crop rotation contribute to a higher yield. Because the goal is to mimic nature, as much 3.1.2.3.1 Crop diversification diversity as possible is created. In the field, Crop diversification is the practice of growing diversity ensures a natural balance. This includes multiple varieties of crops from the same things like cultivating a living soil, preventing or different species in the same area. Crop weeds, conserving water, and reducing pest and diversification, as shown in Figure 20, is one disease attacks on crops. method of constructing a resilient agricultural Biodiversity on top of the soil equals biodiversity system. Crop diversification is also one of below the soil, which include the presence the most environmentally friendly, feasible, of living roots in the soil for the entire year. cost-effective, and rational ways to reduce Maximum cover on top of the soil by plants agricultural risks. Crop diversification also either living or dead serve as armour to the increases resilience, or an ecosystem's ability soil just as our skin protects us from the sun to return to its original productive state after and the rain. It keeps the soil cooler in summer being disturbed, by increasing both spatial and and warmer in winter. This all leads to build-up temporal biodiversity on the farm. of carbon in the soil, which is vital for farms’ sustainability. For every 1% of added carbon to Farmers can also manage production risks the soil, the water holding capacity of that soil by cultivating a variety of crop species. Crop doubles. diversification can be a viable strategy for increasing crop productivity in moisture- stressed, ecologically fragile agriculture systems. Figure 20 Crop diversification by alternating crops at the same time. Source: http://www.arc.agric.za/arc-sgi/Pages/Production%20Systems/Conservation-agriculture.aspx. 209

Climate-Smart Agriculture _ Training Manual Wheat Production 3.1.2.3.2 Mixed cropping between the rows of plant. Intercropped areas Mixed cropping, also known as intercropping, form a canopy that quickly covers the soil, unlike entails planting multiple crops on the same piece single crop plants. of land at the same time. Figure 21 shows wheat In this system food crops are mixed with soil intercropped with clover, which also serves as a enriching crops which: cover crop. Clover has many advantages in this intercropping because it improves soil quality • can fix nitrogen into the soil (legumes) and and reduces the need for artificial fertiliser. cycle plant nutrients; The incorporation of legume biomass into the soil after decomposition improves wheat • grow quickly and provide a lot of above- nitrogen status and grain nitrogen content. It ground (leaf) and below-ground (root) also provides nutrient dense forage for grazing biomass; animals after the harvesting of wheat. Inter cropping also suppresses weeds. Single planted • and improve soil biology, fertility, and areas have more weeds because of the space structure both while growing and decomposing in the soil. Figure 21 Wheat mix cropped with clover. Source: https://www.country-guide.ca/crops/back-to-cover-crop-basics-with-red-clover. 210

Climate-Smart Agriculture _ Training Manual Wheat Production 3.1.2.3.3 Crop rotation 3.1.2.3.4 Advantages of crop Crop rotation, as depicted in Figure 22, is when diversification, mixed cropping and crop crops are planted in the same place at different rotation times. Different crops are alternated on the same field from year to year. The aim is to alternate 1. Soil fertility replenishment – Nitrogen crop types as much as possible. By alternating fixing legumes add top dressing grain crops, like wheat, with broadleaf crops fertiliser to the soil. such as canola, lupin or lucerne the opportunity of diversity in the field is created. Having at least 2. Crops make better use of soil nutrients. three different crops is ideal. The best rotation Because different crops have different is one that also provides fodder for livestock. feeding zones, they will not compete Crop rotation interrupts the disease cycle that for nutrients. The use of different soil can be destructive if the same crop is planted layers by different crops also aids in the year after year. By incorporating legume crops prevention of hard pan. such as lupin, vetch, peas, and legume pastures, one can fix nitrogen from the air for free. The 3. It aids in disease and pest control nitrogen fixed by legume plants will decompose because the introduction of a different the following year, allowing farmers to reduce crop disrupts the life cycles of these the amount of nitrogen fertiliser needed in the pests and diseases. subsequent crop, thus saving money. 4. The soil structure benefits when it is occupied by roots from a variety of plants because: • The roots move the soil; • the roots form a network of living matter that dies and rots to form humus; Figure 22 Crop rotation, starting from top left, lucerne - wheat - barley - lupin - wheat - barley - canola - lucerne again. Source: https://www.grainsa.co.za/improve-your-wheat-yield-with-crop-rotation. 211

Climate-Smart Agriculture _ Training Manual Wheat Production • and when the roots die, they leave Integrated pest management (IPM) is also used, tunnels that improve porosity and which entails using appropriate measures to drainage; discourage the development of pest populations and keep pesticides and other interventions • roots secrete weak acids to dissolve to economically justified levels; reducing or minerals in the soil and then draw minimising risks to human health and the these minerals back up in solutions; environment; and disrupting the agricultural ecosystem as little as possible. The IPM manual • roots also secrete a portion of can be found at https://www.agriseta.co.za/ their photosynthetic energy in the downloads/LearningMaterial/116301LG.pdf. form of sugars that feed microbes, 3.2.1 Insect pests which in turn provide soil mineral Biological measures can be used to control nutrients to the roots. insect pests, here is a link to a manual that can be used: https://agribook.co.za/inputs/ 3.2 CROP PESTS AND PATHOGENS biocontrol/#biocontrol. 3.2.1.1 Aphids Out-of-season and in-season surveys and To prevent oat, rose grain, and brown ear aphid monitoring of insect pests, diseases, and feeding damage, chemical control should be weeds are conducted in order to make control applied at the flag stage, when 25% of tillers recommendations. The use of integrated pest have more than 10 aphids per tiller. Irrigated management practices is also encouraged. fields in areas where BYDV has previously been Soil sampling is done prior to planting to identify found should be treated as a precaution. Aphid soil-borne insect pests and pathogens, as well migration is monitored using suction traps to as weed seeds. Crop seeds are treated to keep provide early warning. insect pests and pathogens at bay. In the case of 3.2.1.2 African bollworm insect pests, traps are built during the growing Chemicals approved for bollworm control are season to collect data that can be used to alert aimed at younger larvae because older larvae farmers. Diseases such as rusts are monitored are less susceptible to chemical treatment. on an annual basis in order to detect new strains When three to four larvae are present per meter and recommend appropriate control. Regular row in dryland conditions, chemical control may field monitoring is critical because previously be used. Spraying can be considered in irrigated unknown diseases/pests may be introduced fields when six to seven larvae are present, due to a specific area as a result of climate change. to the higher seeding rate. Monitoring will aid in the early detection and control of such diseases and pests. Crop diversification can also control weeds effectively. Post-harvest crop protection surveys are also done for storage moths and weevils control especially for small scale farmers who store their produce after harvest. Use of improved post-harvest storage attributes to minimize the application of storage chemicals for insect pests and pathogens. 212

Climate-Smart Agriculture _ Training Manual Wheat Production 3.2.1.3 Leaf miner fly cultivars. The majority of virulent races emerge Rotating wheat with oats to break the pest's locally as a result of genetic mutation in the life cycle is the most effective way to control existing rust population. New rust races can leaf miner fly where severe problems occur be introduced into South Africa from other annually. Leaf miners can live in the soil for up countries via windborne spores or, more to a year. When oats are planted after maize, likely, by adhering to travelers' clothing. As a the hatching leaf miners will most likely look for result, ARC-SGI has been conducting annual a field of wheat, and with no pupae produced rust surveys (monitoring) to detect potentially in the soil, the problem can be reduced or dangerous rust races in a timely manner, and eradicated. the results have been used to continuously 3.2.2 Diseases improve wheat rust resistance in cultivars that 3.2.2.1 Rusts have been released on a regular basis. Growing resistant cultivars and applying Fungicides can be used to control wheat rusts fungicides are the two most common methods when resistant cultivars are not available or of wheat rust control. Rust-resistant cultivars when resistance in existing cultivars breaks offer an efficient and environmentally friendly down due to the emergence of new races. method of rust control. As a result, rust Excessive use of fungicides, on the other hand, resistance has been a key component of the is harmful to the environment and may pose a ARC-Small Grain wheat breeding objectives health risk to farmers and farmworkers. It may (ARC-SG). Several resistant cultivars have been also increase the likelihood of the emergence developed in recent years. The resistance of fungicide-resistant rust strains, rendering the status of commercially available cultivars is chemicals ineffective. As a result, fungicides tested with relevant rust races once a year, and should only be used on susceptible cultivars the results are published by ARC-SG in the Small where rusts are likely to cause significant yield Grain Production Guideline on a regular basis. loss. Fungicides should not be used on resistant Farmers can use this information to decide wheat cultivars. which cultivar to grow in a particular production The following manual can be consulted for use area. to control wheat stem rust (De Villiers et al, Using resistant cultivars to control wheat rusts 2019). presents some challenges. One of the most 3.2.3 Weeds significant limitations of resistant cultivars is Weeds can be controlled using both IPM and that rust-causing fungi frequently acquire new CA strategies. The IPM manual can be found virulence to overcome resistance in existing at https://www.agriseta.co.za/downloads/ LearningMaterial/116301LG.pdf. 213

Climate-Smart Agriculture _ Training Manual Wheat Production 4 CONCLUSION dates to accommodate new temperature and precipitation patterns is the simplest and least Climate change's effects on crop production expensive adaptation. It is critical to plant wheat must be thoroughly understood before effective cultivars at the appropriate time to ensure mitigation strategies can be implemented. In flowering occurs during the optimal window order for mitigation strategies to work, it is for maximum grain yield potential. The optimal also necessary to practice the timing of cultural flowering window is determined by a balance of practices in wheat production. water used during canopy development, grain One of the strategies to minimise the application formation, and grain-filling phases, as well as of chemicals such as pesticides and fungicides the frequency and severity of frosts decreasing. while also protecting the environment is to Crops that flower too early are more likely to develop high yielding and widely adapted wheat be frost damaged, whereas crops that flower genotypes with increased water-use efficiency, too late are more likely to be subjected to high heat tolerance, and resistance to major diseases temperatures and water deficits, which can and pests (Tadesse et al, 2018). The use of limit grain formation and grain filling. these well-adapted varieties; a diverse range of The wheat crop can also be planted earlier to crop species and varieties grown in associations, avoid terminal heat, but this increases the risk intercrops, or rotations; pest control through of being exposed to heavy rain (which is largely integrated pest management; and the use unpredictable). As a result, the timing of sowing of conservation agriculture and sustainable as well as the wheat production systems must mechanization can maintain healthy soils and be adjusted. Because of the time saved with efficiently manage water to achieve the highest direct seeding, CA allows for an earlier wheat possible productivity per unit of input. sowing date when compared to the traditional When one cultivar is affected and the other is tillage-based wheat production system. not, cultivating a diverse suite of cultivars in In irrigated systems, increasing irrigation associations, intercrops, and/or rotations can efficiency (e.g., through deficit irrigation, be beneficial (FAO, 2011). precise water applications, high-efficiency It is critical to understand the correct operations pumps), reducing water losses, and improving to perform on the small grain field, the correct water allocation and demand management time to perform them, the correct way to optimises yields per volume of water applied, perform them, as well as why the operations reduces greenhouse gas emissions, and results are performed, why they are performed at in energy efficiency gains, primarily in fuel use. a specific time, and why they are performed In addition, introducing supplemental or deficit in a specific manner. Planting rates and irrigation in rain-fed conditions is an effective timing are two examples of these. Knowing way of maintaining or increasing grain yield in planting dates and seeding rates determines dryland conditions. the best combinations, and shifting planting 214

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Climate-Smart Agriculture _ Training Manual Wheat Production Myers SS, Smith MR, Guth S, Golden CD, Vaitla B, Mueller ND, Alan D, Dangour AD & Huybers P (2017). Climate Change and Global Food Systems: Potential Impacts on Food Security and Undernutrition. Annu. Rev. Public Health. 38: 259-77. https://doi.org/10.1146/annurev-publhealth-031816-044356. Parmesan C, Yohe G (2003). A globally coherent fingerprint of climate change impacts across natural systems. Nature. 421: 37-42. S´anchez B, Rasmussen A & Porter JR (2014). Temperatures and the growth and development of maize and rice: a review. Glob. Change Biol. 20: 408-417. Schlenker W, Roberts MJ (2009). Nonlinear temperature effects indicate severe damages to U.S. crop yields under climate change. PNAS 106:15594-15598. Smith CMhRa,nMgey.e8r:s8S3S4(-2803198. )h.tItmpsp:a//cdtooif.oarngt/h1r0o.p1o03ge8n/sic41C5O528e-m01is8s-i0o2n5s3o-3n.global human nutrition. Nature Clim Southern African Grain Laboratory (SAGL) (2018). South African Wheat crop quality report 2017/2018 season. Pretoria: SAGL. Southern African Grain Laboratory (SAGL) (2019). South African Wheat crop quality report 2018/2019 season. Pretoria: SAGL. Tadesse W, Bishaw Z & Assefa S (2018). Wheat production and breeding in Sub-Saharan Africa - Challenges and opportunities in the face of climate change. International Journal of Climate Change Strategies and Management 11 (5): 696-715 DOI 10.1108/IJCCSM-02-2018-0015. Trnka M, Feng S, Semenov MA, Olesen JE, Kersebaum KC, Rötter RP, Semerádová D, Klem K, Huang W, Ruiz-Ramos M, Hlavinka P, Meitner J, Balek J, Havlík P & Büntgen U (2019). Mitigation efforts will not fully alleviate the increase in water scarcity occurrence probability in wheat-producing areas. Science Advances DOI: 10.1126/sciadv.aau240 Ziska LH, Teasdale JR & Bunce JA (1999). Future atmospheric carbon dioxide may increase tolerance to glyphosate. Weed Sci. 47: 608-615. Ziska LH (2008). Rising atmospheric carbon dioxide and plant biology: the overlooked paradigm. DNA Cell Biol. 27: 165-172. 217

Climate-Smart Agriculture _ Training Manual Wheat Production LIST OF FIGURES Figure 1 Russian wheat aphid. 192 194 Figure 2 Oat aphid. 194 195 Figure 3 Rose grain aphid. 195 196 Figure 4 Brown ear aphid. 197 197 Figure 5 African bollworm and the damage it causes. 199 200 Figure 6 Leaf rust. 200 201 Figure 7 Stem rust. 201 201 Figure 8 Stripe rust. 202 Figure 9 Barley yellow dwarf virus infected wheat leaves. 203 204 Figure 10 Wild buckwheat seedling. 205 Figure 11 Wild buckwheat in an oats field. 208 209 Figure 12 Young Chenopodium plant. 210 Figure 13 Chenopodium seeds. 211 Figure 14 Avena plant. Figure 15 Avena spikelets. Figure 16 Healthy loose soil with good structure versus unhealthy cloddy soil with poor structure. Figure 17 Earthworms in healthy soil. Figure 18 Wheat seedlings growing on healthy soil with well decomposed humus. Figure 19 Soil covered with cover crop between rows of wheat crop. Figure 20 Crop diversification by alternating crops at the same time. Figure 21 Wheat mix cropped with clover. Figure 22 Crop rotation, starting from top left, lucerne - wheat - barley - lupin - wheat - barley - canola - lucerne again. 218

Climate-Smart Agriculture _ Training Manual Wheat Production LIST OF TABLES Table 1 Wheat production overview over three seasons. 188 Table 2 Resistance(R)/Susceptibility (S) of wheat germplasm with 193 resistant genes against five South African biotypes (RWASA1-RWASA5). 198 Table 3 Environmental conditions required for the wheat rusts. 207 Table 4 Effects of different management practices on gains and losses of organic matter, beneficial organisms and pests. 219

MODULE 6 Subtropical Fruit Production Compiled by R J du Preez ([email protected]) Agricultural Research Council – Tropical & Subtropical Crops

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Table of Contents 1 INTRODUCTION 222 1.1 CLIMATE CHANGE AND ITS IMPACT ON AGRICULTURE 222 1.2 GREENHOUSE EFFECT 222 1.2.1 Causes for rising emissions 223 1.3 IMPACT ON PRODUCTION 223 2 SUBTROPICAL FRUIT PRODUCTION IN RSA 227 2.1 OVERVIEW 227 2.2 CLIMATIC REQUIREMENTS FOR SUBTROPICAL CROPS 230 2.2.1 Citrus 230 2.2.2 Avocado 232 2.2.3 Mango 233 2.2.4 Banana 235 2.2.5 Litchi 236 2.2.6 Pineapple 237 2.2.7 Guava 238 2.2.8 Papaya 238 2.2.9 Granadilla 239 2.2.10 Macadamia 239 2.2.11 Pecan 240 3 MITIGATION & ADAPTATION 241 3.1 ORCHARD MANAGEMENT 243 3.1.1 Water availability 243 3.1.2 Orchard considerations to take into account 243 3.1.3 Cultivar selection 245 3.1.4 Diversifying crops 245 3.2 CONSERVATION AGRICULTURE 245 3.3 INTEGRATED FARMING SYSTEMS 246 3.3.1 Intercropping 247 3.3.2 Mulching 248 3.4 INTEGRATED PEST MANAGEMENT 249 3.5 WATER HARVESTING 250 3.6 INDIGENOUS TREE SPECIES / AGROFORESTRY 251 4 CONCLUSION 253 5 REFERENCES AND RESOURCES 254 255 LIST OF FIGURES 255 LIST OF TABLES 221

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Climate Change refers to a cultivation in specific locations may no longer change in the state of the be so, and new crop varieties may become climate that can be detected suitable for cultivation in areas where they are not currently suitable. These consequences are 1 INTRODUCTION(e.g., by statistical tests) by already being seen in subtropical places. changes in the mean and/or 1.2 GREENHOUSE EFFECT 1.av1anrd iCatbhLialIittMylaosAtfsiTtfsoEcrhaaCnraHecxttAeernNisdteiGcdsE AND ITS The 'greenhouse gas effect' is critical for the oper rloiIonMdgeoPrf.tACimliCmeT,aotefOtcehnNadneAgceaGmdeRasyICULTURE growth and survival of life on Earth: without it, temperatures on Earth would be 19°C below ThbpeeroaccgaerusiscseeudsltoburyreenxaitnteudrrnuaalslitfnrotyrecirninnSagols uthAfricaisgrowing freezing point on average. The greenhouse gas incsurechasaisnsgolylar sceycnlesimtivoedultaotionp,opulation growth, effect occurs when some of the sun's short- higvholcainnipc uertupptiorincse,sa,ndcclhimroantice unpredictability, wave energy is absorbed by the Earth's surface afmlnuoch2dco0ustm0tmucl7ypaal)iot.nmtesocisathitsoateihnnggenocerihsfcliaiaocnnnauadgnntetumtl.rsyoyeAs'f(sprIgoPhrvCmeiucCriul,cnyleteuarrarabtloiliptyyreoatdrou, ochtwaivriinsthgy and reemitted mostly in the infrared band. weather events. Climate change has an impact Some gases in the Earth's atmosphere function on agricultural systems in the following ways: like greenhouse glass, trapping the sun's heat and preventing it from escaping into space. • rain quantity and distribution, and therefore Many of these gases are naturally occurring, but water availability; human activity is increasing their quantities in the atmosphere, particularly: • extreme events such as floods and droughts; • carbon dioxide (CO2) • increased temperatures; • methane • shifting seasons, all of which have a • nitrous oxide • fluorinated gases substantial influence on fruit output. Agro-climatological indicators' frequencies, averages, extremes, deviations, threshold exceedance, regional variability, and trends are essential for monitoring and reducing agricultural risk. Furthermore, climate-related temperature and rainfall fluctuations across South Africa have resulted in altered agri- ecozones. Crops that are now suitable for 222

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Carbon dioxide (CcrOe2a)teisd the most prevalent 1.2.1 Causes for rising emissions greenhouse gas by human activity, There are various factors that contribute to accounting for approximately 64% of man- rising emissions and they include: made global warming. Its concentration in the atmosphere is now 40% greater than before • Burning coal, oil and gas: Carbon dioxide industrialization began. and nitrous oxide are produced when coal, oil, and gas are used for transportation, Other greenhouse gases are released in lesser heating, and industrial output. quantities, but they trap heat considerably more setfrfoicniegnetrlyintshoamneCcOir2cuanmdstaarnecehsu.nMdreetdhsanoef • Clearing of forests by humans times (deforestation): Trees contribute to is responsible for 17% of man-made global cthliemaattemoresgpuhlearteio. nWbhyenabtsreoerbsinargeCcOh2opfrpoemd warming, whereas nitrous oxide is responsible down, the positive impact is eliminated, and for 6%. the carbon stored in the trees is released into the atmosphere, contributing to the Human activity has increased the amount of greenhouse effect. greenhouse gases, particularly carbon dioxide, in the atmosphere. The increased warming • Expanding cattle farming: When cows and generated by these emissions is known as the sheep digest their meal, they create a lot of ‘anthropogenic greenhouse gas effect,' and it is methane. one of the primary drivers of climate change. • Use of fertilisers containing nitrogen: Nitrous oxide emissions are produced by nitrogen-containing fertilisers. 1.3 IMPACT ON PRODUCTION According to FAO (2013), the world's population will grow by an additional 2 billion people between 2013 and 2050, with the majority of these individuals coming from poorer nations. Based on current income and consumption growth trends, the FAO forecasts that agricultural production would need to expand by 60% by 2050 to meet projected food and feed demand. Using a business-as-usual scenario, an increase in agricultural production of 60% will be challenging owing to the negative effects of climate change. Climate-Smart Agriculture addresses food security and climate issues concurrently, therefore integrating the three pillars of sustainable development (economic, social, and environmental). It is supported by three major pillars. 223

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 1. Increasing agricultural production and are expected to see an overall decrease in incomes in a sustainable manner precipitation in semi-arid areas, increased variability in rainfall patterns, and a rise in 2. Adapting to and building resilience to temperature at low latitudes. Agricultural output climate change will have to deal with more unpredictability in water supplies, with the greatest impact felt 3. Reducing and/or eliminating in food-insecure areas dominated by rain-fed greenhouse gas emissions when agriculture. possible. Climate change adaptation for agricultural cropping systems requires greater resilience As a result of a number of technical, political, to both surplus water (due to high intensity financial, and socioeconomic limitations, rainfall) and scarcity of water (due to prolonged studies pertaining to greenhouse gas reduction, dry periods) (FAO, 2007). To strengthen the sustainably increasing agricultural productivity resilience of these rain fed production systems, and incomes, and adapting to climate change adaptation methods focused on increased activities are generally not addressed together. water infiltration, soil moisture retention, water Climate change will aggravate existent patterns collection, and small and dam-based irrigation of food poverty and vulnerability. Agriculture, development would be necessary. rural livelihoods, and food security are closely connected to the issues of climate change in the twenty-first century. The next 50 years Figure 1 Maximum and minimum temperatures in South Africa with projected changes due to climate change effect. Source: Schulz, R., 2017. 224

Climate-Smart Agriculture _ Training Manual Subtropical fruit production The following techniques and tactics can help Temperature also influences the amount and to mitigate the predicted harmful effects of quality of blooms, which has a direct impact climate change: on the season's fruiting potential. Low night temperatures are required by some fruit crops, • Identifying and implementing local disaster such as mandarins, to create beautiful fruit risk reduction activities integrating national skin colour. The sweetness of most subtropical and sub-national early warning systems; climate fruits rises when diurnal temperature Identifying current vulnerabilities and risk variations grow, which is influenced by reduction solutions with the participation unfavourable climatic conditions. These are of the community; just a few examples, but the true picture is considerably broader, and if appropriate steps • Increasing communities' abilities to manage are not done, the situation may worsen. their resources (e.g., savings, credit We must discover ways to produce more food, schemes, agricultural inputs, agricultural adapt to shifting weather patterns, and prevent productivity, land usage, and so on); additional climate damage, all while providing opportunities for men and women involved in • Increasing the use of technology tools food production. To tackle these interconnected to mitigate the hazards associated with issues, food systems must become more climatic variability (for example, disaster efficient while also becoming more resilient to information management systems); changes and shocks. Agriculture must evolve to make greater use of natural resources, • Raising farmer awareness and strengthening producing more with less land, water, energy, local institutions in support of national and other inputs. disaster management policies; • Establishing partnerships between regional and national research institutes, extension services, and farmers. Climate change is a serious threat to humanity. No one can avoid its devastating repercussions, and its influence on the plant kingdom cannot be disregarded since humans rely on plants for food security and the preservation of ecological equilibrium. Although perennial crops are naturally resilient, they are unable to offset severe climate change. Among them are fruit trees, which play an important role in global nutritional food security and enrich the environment with their diverse species. Changes in precipitation patterns, rising temperatures, and uncertainty in climate forecasting all have a significant influence on tree crops. Most fruit crops, including mango, papaya, guava, and others, experience flower drop when severe low temperatures predominate during flowering, reducing fruit output. 225

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Practical activity 1 Describe how climate change is likely to influence agriculture and other elements of people's lives. 1. Divide participants into groups to explore how greater and lower temperatures, as well as unpredictable rainfall, would influence their location. 2. The following points should be addressed: • fruit production • natural resources and the environment • economic and social factors Each group is required to report back to the plenary. A discussion around regarding their results must be facilitated. 226

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 2 SUBTROPICAL FRUIT PRODUCTION IN RSA 2.1 OVERVIEW possible impact on the natural environment. Commercial production management is about Subtropical fruit originates from the tropical and achieving these objectives efficiently and cost subtropical regions of the world. Subtropical effectively. fruit crops are characterized by relatively Subtropical fruit crops are characterized by poor winter hardiness. The particular climatic relatively poor winter hardiness. They have a long requirements of some types of subtropical fruit growing period and require stable conditions make their cultivation only possible in certain during their winter dormant period. Individual specific areas of the country. In the absence crops vary greatly in their frost resistance. of effective production practices, trees will not Subtropical crops also require various amounts produce fruit suitable for the market. of heat during their growing periods. Fruit and nut production is largely concerned The most important subtropical crops in South with management of the practices and processes Africa include citrus fruits, banana, avocado, that manipulate the tree to produce high mango, litchi, papaya, guava, granadilla, yields of marketable fruit and nuts. Production pineapple, macadamia and pecan. Minor management, together with the selection of subtropical crops in SA are coffee, ginger, superior varieties and plant improvement, can coconut, cashew and pepper. The particular be seen as an on-going effort to influence the climatic requirements of some types of natural tendencies of the tree. subtropical fruit make their cultivation only Consumers want the fruit and nuts of their possible in certain specific areas of the country. choice to be available at all times. Fruit should In general, subtropical fruit types require look good, be unblemished, well-coloured warmer conditions and are sensitive to large (superior exterior quality), taste good (high fluctuations in temperature and to frost. Frost interior quality) and be of the right size. At the free areas in South Africa are suitable for same time, the producer wants orchards that subtropical crop production although other will provide high yields over an orchard lifespan, factors including rainfall and soil also impact which could exceed half a century. On top of suitability of areas. Figure 2 indicates the areas all this, the orchard must be managed in such in South Africa that are frost free. a way that production practices have the least 227

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Figure 2 Horticultural Zones in South Africa. Source: http://pza.sanbi.org/horticultural-zones. 228

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Table 1 Description of Horticultural Zones. Source: http://pza.sanbi.org/horticultural-zones. Zone Description Mean monthly Frost Rainfall 1 Summer rainfall – minimum temp Dry frost free suitable for subtropical – coldest month winters The most southern 2 crop production 5°C to 10°C part receives Frost-free - frost occasional winter Coastal winter rainfall – 0°C to 10°C occasionally occurs rainfall and has cooler some areas suitable for in parts of the zone, conditions (lower selected subtropical crop but it is extremely temperatures). In production light and is short- some locations, strong lived. winds occur. Strong winds in areas along the coast 3 Winter rainfall (Karoo). -5°C to 5°C Light frost - Summer rainfall is Certain subtropical crops northern and experienced in the can be produced here coastal regions of eastern sections, if they receive enough Namaqualand frost whilst winter rainfall water and are planted in is absent or very is seen in the western frost-free regions. light. parts. Frost in winter is Rainfall occurs 4 Summer rainfall (Karoo/ <-5°to 5°C severe primarily in the Highveld) summer, with dry Frost winters, however 5 Summer rainfall -5°C to 0°C rainfall is quite low (Bushveld) in the north-western region. The eastern part receives a considerable amount of rainfall, although it becomes drier as one moves north and west. 229

Climate-Smart Agriculture _ Training Manual Subtropical fruit production South Africa's primary subtropical fruit Moisture is another constraint in citrus production areas are in Limpopo, Mpumalanga, production. Because rainfall is frequently KwaZulu-Natal, and the Eastern Cape. Fruits unevenly distributed and, in most situations, cultivated on the Western Cape include insufficient, moisture must be supplemented granadillas and guavas. by irrigation to guarantee that moisture stress Citrus, avocados, mangoes, bananas, and litchis does not inhibit development and output. are significant crops for the country since they 2.2.1.1 Temperature prior to flowering have both high growth potential and are in the Citrus trees are subtropical in nature and labor-intensive quadrant. cannot withstand harsh frosts. Citrus cultivation in South Africa is thus limited to places with 2.2 CLIMATIC REQUIREMENTS warm and nearly frost-free winters, when FOR SUBTROPICAL CROPS temperatures seldom (once per several years) fall below –2°C and almost never fall below 2.2.1 Citrus –3°C. If no shelter is given, the average lowest temperature for the coldest month should not Citrus trees are subtropical in nature and drop below 2°C to 3°C. cannot withstand harsh frosts. Citrus cultivation Moisture is another constraint in citrus in South Africa is thus limited to places with production. Because rainfall is frequently warm and nearly frost-free winters, when unevenly distributed and, in most situations, temperatures seldom (once per several years) insufficient, moisture must be supplemented fall below –2°C and almost never fall below by irrigation to guarantee that moisture stress –3°C. If no shelter is given, the average lowest does not inhibit development and output. temperature for the coldest month should not Flowering should occur nearly entirely in the drop below 2°C to 3°C. spring, with these spring blooms producing a substantial fruit yield 7 to 12 months later. This, however, varies with cultivar. In more tropical locations, the blooming pattern is less distinct, and main season yields are often significantly less. Winters in South Africa are typically cold enough for good in-season crops, particularly Valencia oranges and grapefruit, to set. In warmer climates, however, navel trees generate lower yields and fruit. Cold requirements for navel manufacturing regions typically have a mean temperature of 12 to 13°C. The mean temperature must be below 13°C for the tree to go dormant. 230

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Winters in South Africa are typically cold to support following consistent blooming and enough for good in-season crops, particularly fruit-set. This results in delayed blooming and Valencia oranges and grapefruit, to set. In fruit maturation. This is especially beneficial warmer climates, however, navel trees generate because the fruit matures during a time of lower yields and fruit. Cold requirements for rapidly decreasing temperatures. Fruit color navel manufacturing regions typically have a becomes good under these conditions, and the mean temperature of 12 to 13°C. The mean decline in acid content tends to be moderate temperature must be below 13°C for the tree and under control. to go dormant. 2.2.1.4 Valencia orange Navels must consequently approach hibernation Valencias have a rather long fruit development in the winter. As the mean temperature for the time, thus the in-season crop usually develops coldest month increases over 14°C, the odds in the middle of winter or early spring. Even in of growing consistently productive harvests warmer climates, winter temperatures are low decrease. enough to assure good colour and a decrease in 2.2.1.2 Effects of climate on fruit quality acid content in the fruit. The fall in acid content The climate has a significant impact on the is slowed in colder areas by low temperatures, quality of citrus fruits. The fact that a region and warmer spring weather is necessary for will be labeled as a \"good navel area\" or a \"poor the acid level to drop sufficiently low prior to grapefruit area\" regardless of soil differences or harvesting. management measures is ample confirmation Because of these qualities, the Valencia is more of the role that climate plays in generating tolerant to a wider variety of winter conditions. quality fruit. It cannot be overstated how Valencia has summer environmental needs that important it is for new citrus enterprises to are similar to those of the navel, albeit it is more thoroughly evaluate the climatic needs of the tolerant of warm, humid circumstances that various varieties in order to produce only top- result in lower Total Soluble Solids (TSS) levels quality fruit. in navels. 2.2.1.3 Navel orange 2.2.1.5 Grapefruit Negative climatic conditions have a negative Grapefruit cultivars have a brief period of fruit impact on navels. Much of South Africa's development. As a result, grapefruit production subtropical area is unsuited for its cultivation. thrives in hot, humid climates with short, mild Only in the dead of winter can high-quality winters. navels be created. The average maximum 2.2.1.6 Lemons daytime temperature for the three coldest Lemon cultivation is well suited to a broader months should be between 22 and 23°C. Areas variety of climatic conditions. During February with colder winters typically have longer winters, and March, hotter locations yield larger fruits. resulting in a higher degree of dormancy. This In hotter climates, the fruit is larger. The primary allows for a greater accumulation of reserves 231

Climate-Smart Agriculture _ Training Manual Subtropical fruit production crop matures in colder locations from May to cultivars. The ideal temperature for growth July. Fruit size is superior (smaller) than in warm is between 25 and 28°C. The humidity level climates. Smaller fruit sizes are desirable, and should ideally be more than 60% smaller fruit receives higher export prices. The • Mexican varieties evolved in Mexico's colder locations produce two or three minor cold, subtropical highland woods, and crops in addition to the main crop at different mature trees can resist temperatures as periods of the year. low as –4°C. Flowers are readily destroyed 2.2.2 Avocado by cold and should not be planted in frost- prone locations in August and September. There are three most well-known avocado A humidity range of 45% to 60% should races, each with its unique set of climatic needs suffice. The ideal temperature for growth is for adjusting to its native habitat. 20°C to 24°C • Guatemalan cultivars originated from • West Indian cultivars evolved in the humid, Guatemala's tropical highlands and require tropical lowlands of Central America and are a mild, tropical climate with no temperature best adapted to hot, humid environments or humidity extremes. The trees can with heavy summer rains. They are, survive light cold down to –2°C, but the however, highly sensitive to dryness blooms are extremely frost sensitive. High and do not handle frost well (minimum temperatures of around 38°C, especially temperature of 1.5°C), as do other avocado when paired with low humidity, have the potential to trigger blossom and fruit drop. A humidity level of at least 65% is necessary • The Fuerte cultivar, which is the most widely planted in South Africa, is most likely a natural hybrid of Mexican and Guatemalan races, and it has more climate resistance (particularly to cold) than pure Guatemalan varieties 2.2.2.1 Temperature • The ideal growing temperature for avocado is cool subtropical settings with a mean daily temperature of 20°C to 24°C • High temperatures, particularly during flowering, are not well tolerated • Except during flowering and fruit set, light frost may be tolerated (August and September) • The lowest temperature for survival is –4°C, however avocados are sensitive to frost during blooming • The Fuerte cultivar is more susceptible 232

Climate-Smart Agriculture _ Training Manual Subtropical fruit production to adverse weather conditions during 2.2.3 Mango flowering than other varieties • Because of fruit and blossom drop, hot, dry Mango trees can withstand a broad variety of weather may result in poor yields climate conditions. The crop may be grown • The daily mean temperature should be effectively in a variety of circumstances, including above 18.5°C during the flowering season extremely hot and humid temperatures, cold 2.2.2.2 Humidity and dry conditions, and extremely hot and High humidity levels are preferable because arid conditions. The trees can live in marshy they reduce the negative impacts of stress circumstances for long periods of time, but they conditions (especially high temperature), which can also survive in places with less than 300 mm are crucial during blooming and fruit set. of annual rainfall and temperatures as high as South Africa's mist-belt regions are particularly 45°C. well suited to this use. Around 14:00, the 2.2.3.1 Temperature humidity ought to be higher than 50%. 2.2.2.3 Rainfall • The average minimum temperature during Water stress affects all commercially produced the winter should preferably be above 5°C. avocado cultivars in South Africa. An annual rainfall exceeding 1000 mm is desired, and it • When the trees are in full bloom, cold should be evenly distributed, with the only dry temperatures can cause the fruit to mature months being in June and July. However, the to about the size of a golf ball, turn yellow, majority of eligible locations in South Africa and then abort. Fruit drop causes a decrease have a dry spell during flowering, needing in yield. additional watering. 2.2.2.4 Wind Avocados have fragile branches that are readily destroyed by wind. The bulk of flaws that cause fruit to be downgraded are most likely caused by wind damage. Climate-smart, the ideal places for commercial avocado cultivation are thus the cold, subtropical sections of Mpumalanga and the Northern Province, as well as KwaZulu-Natal, where rainfall is quite high and mist occurs regularly. 233

Climate-Smart Agriculture _ Training Manual Subtropical fruit production • Mango trees thrive in places with extremely • Certain cultivars, including as Zill, Haden, high temperatures (45°C). However, when and Kent, are more prone to fruit loss than temperatures surpass 46°C, vegetative others in windy circumstances growth ceases, especially if little humidity is present. • Damage by wind can be minimised by: »» Avoiding locations with high winds • For optimum growth and production, the »» Creating windbreaks on the upwind average maximum temperature should side of prevailing winds, such as range between 27 and 36°C. manmade buildings or fast-growing trees. To prevent producing a funnel • Certain cultivars are less resistant of high effect, mango orchards should be temperatures and low humidity, resulting planted so that the rows run diagonally in sunburned fruits (Sensation and to the prevailing wind direction Keitt). Tolerant cultivars include Neldica, »» Pruning non-bearing flower panicles as Tommy Atkins, Chené, Kent, Ceriese, and soon as it is clear that they will not yield Kensington. fruit, since they leave scratch marks on the fruit when they turn dry and hard 2.2.3.2 Humidity and rainfall 2.2.3.4 Elevation From October until the fruit is harvested, the Mangoes grow successfully at elevations ranging average relative humidity for mango cultivation from sea level to 1200 m in the tropical and in South Africa should be 55% or less. subtropical areas. At higher elevations, however, production diminishes. Mango production The rainfall should ideally not exceed the over 600 m altitude is widely regarded to be following: financially unviable in South Africa. 2.2.3.5 Soil requirements September: 50 mm October: 85 mm Mangoes thrive and produce well in a wide range of soil conditions. Mangoes grow successfully November: 110 mm December: 140 mm under irrigation in soils with an unobstructed depth of more than 1 m. However, if irrigation is January: 140 mm February: 140 mm carefully planned, there should be no difficulty on soil with a depth of 750 mm, as long as any soil The relative humidity and rainfall reported or rocky layers that restrict root development here are optimal for the growth of disease-free to 750 mm soil depth enable surplus water to fruit, but not for maximum output. Irrigation is drain readily. critical in areas where mangoes are grown due A sandy-loam or loam soil (with a clay percentage to limited rainfall. of 15-25%) is best for mango production under 2.2.3.3 Wind irrigation, but soils with a clay content of up to 50% are also appropriate. • Scratches on fruit can be caused by wind Moisture losses from transpiration and (even mild gusts). Through these wounds, harmful fungus and bacteria can penetrate the fruit. Fruit bearing marks are not acceptable for commercial purposes • Winds that are too strong can induce fruit loss, resulting in decreased yields 234

Climate-Smart Agriculture _ Training Manual Subtropical fruit production evaporation are so minimal in some places variation in day and night temperatures, as (owing to humidity, temperature, and rainfall well as the seasonal temperature extremes conditions) that the soil remains wet throughout encountered in the subtropics throughout both the year, preventing tree withering. Mangoes winter and summer. may be cultivated in dry land circumstances if 2.2.4.1 Rainfall the soil moisture retention ability is such that Climate significantly limits banana cultivation in it can give moisture to the plants during drier South Africa's subtropical zones, since optimum seasons. Such soils have a depth of at least 600 circumstances do not exist elsewhere in the mm and a clay concentration of 15 to 30%. nation. Rainfall is insufficient, and distribution 2.2.4 Banana is poor, although this may be greatly improved with additional irrigation (see section on The world's largest banana-growing regions irrigation). are located between the equator and latitudes 2.2.4.2 Temperature 20° North and 20° South. The climate in these More importantly, in midwinter, air temperatures places is mostly tropical, with relatively modest in banana regions drop every night to between temperature changes from day to night and 12 and 5°C, and occasionally much lower. Cold from summer to winter. South Africa's banana- night temperatures induce yellowing and a growing zones, on the other hand, are located variety of bunch issues such as November dump, between 24 and 31 degrees south, with choke throat, and under peel discoloration, typical subtropical temperatures. The primary all of which affect yield and quality. The daily distinction between our local subtropical temperature range approaches optimum only climate and tropical climates is the considerable during the three to four summertime months when daily low temperatures are often above 18°C. During summer heatwaves in the subtropics, peak temperatures on summer afternoons can sometimes reach between 40°C and 45°C. This is almost as bad for banana plants as cold temperatures since it causes wilting, permanent leaf burn lowers leaf area, and reduces photosynthetic efficiency. Heat stress also reduces bunch production and quality during bloom initiation or fruit development. Choke throat in bananas is a well-known phenomena that occurs from June through September, when normal leaf development is 235

Climate-Smart Agriculture _ Training Manual Subtropical fruit production hampered by cold winter temperatures. The dry winds cause water stress and transient issue is that a bunch attempting to emerge wilting, causing physiological damage to the through the top of the pseudostem is thwarted plant. by leaf bases with short internodes that have gotten compressed and crowded at the aperture. 2.2.4.3.3 Drought This behavior is particularly pronounced in In South Africa, nearly all bananas are irrigated. Dwarf Cavendish, whose leaves get rosetted However, when the supply of irrigation water is and crowded at the apex of the pseudostem reduced or eliminated due to drought, the plants during cold weather. Unless temperatures are suffer fast. Heat stress and leaf burn occur more really low, it seldom occurs with tall varieties. quickly when soil water content is reduced than The optimum temperature for banana flower when soil is well-watered. Drought causes tiny, initiation is around 22°C. When mean nighttime stunted plants with wilted, yellow leaves, delays temperatures fall below 10°C, flower initiation is in flowering, choking throat even in July, and greatly impacted by the cold, leading in a higher little bunches with shriveled, blackened fingers. or lesser degree of November dump. Because of the diminished growth potential and 2.2.4.3 Other climatic problems lower temperatures, the impacts of drought are significantly less severe in the winter. 2.2.4.3.1 Hail 2.2.5 Litchi Almost every year, a strong hailstorm devastates and destroys certain subtropical banana plantations in South Africa. Hail damage to banana bunches can be mitigated in part by using polyethylene covers, depending on the intensity of the hail and the thickness of the cover. Covers provide some protection during mild hail, and they should be seriously considered for both wind and hail protection this summer. 2.2.4.3.2 Wind Wind may cause a variety of problems in a banana plantation. Winds of more than 50 km/h create \"blowdowns,\" which are occasionally responsible for catastrophic crop losses. In the subtropics, high seasonal winds (20 km/h to 50 km/h) produce leaf tearing, which can impair production when severe. Winds of 10 km/h to 20 km/h can also degrade fruit quality by increasing leaf and dust abrasion. Finally, hot, 236

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Litchis grow best in a subtropical environment 2.2.6 Pineapple with hot summers and cool, frost-free winters. Low winter temperatures are critical for Pineapple thrives in a warm, humid area with inducing the physiological changes required to temperatures ranging from 15°C to 32°C. Daily induce bloom initiation. Flowers and new shoots mean temperatures of 23°C - 24°C are said to be can be damaged by temperatures below 0°C. ideal for pineapple acid and sugar levels. High Frost-free parts of South Africa with significant temperatures above 35°C are unfavourable for summer rainfall and humidity (particularly fruit growth, especially if relative humidity is the Mpumalanga Lowveld, the Soutpansberg low. Sun scorching occurs when the fruits are area, and the KwaZulu-Natal coastline area) exposed to direct sunlight and temperatures are therefore best suited. The climate must over 32°C. meet the following requirements for good litchi Pineapples thrive in climates with rainfall production: ranging from 760 to 1000 mm. However, irrigation is required when yearly precipitation • During the summer, the average monthly falls below 500 mm or when low rainfall occurs maximum temperature must be less than in successive months. 32°C but greater than 26°C High humidity (daily mean > 75%) prevents sunburn and promotes development in places • For the three to four winter months, the with limited rainfall. If frost does not occur, average monthly minimum temperature pineapples may be cultivated up to a height of must be greater than 6°C but less than 14°C 1,100 m above sea level. • From October through fruit maturation, the relative humidity must be greater than 50% 2.2.5.1 Water High summer rainfall supports optimum fruit development and yield in litchi cultivation. From blossoming until the fruit can be picked, which is from August to January, adequate water must be provided. Sufficient soil moisture must be provided throughout the blooming season and for 7 to 8 weeks following flowering since this is the most crucial phase for fruit set and the beginning of cell division in the young fruitlet, particularly in the skin and the early embryo (seed). 237

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 2.2.7 Guava 2.2.8 Papaya Guavas are fairly versatile and thrive in tropical Papayas thrive in hot climates. In South Africa, and subtropical climates. In locations with a the ideal temperature range for papayas is distinct winter season, yield and quality tend between 25°C and 28°C, and output typically to rise. They do, however, grow best in places peaks between September and November. where there is no frost. They can, however, They can withstand light frost provided they are flourish in most regions where the winters are shielded from cold winds. not too harsh, and the young trees should be Papayas thrive and yield well in a broad range of protected if planted in areas where there is soil conditions. The best soils are loamy. The root periodic frost. Mature trees, on the other hand, system may penetrate to a depth of 2 m under can withstand the rare cold. Cold winds should favourable conditions, although the majority of be kept away from trees. the roots responsible for nutrient absorption Guavas may be cultivated up to 1515 m above are located in the top 500 mm. Soils must be mean sea level. Drought tolerance is higher in adequately drained since diseased roots might older plants. Guava trees are highly resilient develop if the soil becomes too moist. and can grow in a variety of soil types, although they are susceptible to water logging. Deep, loamy soils that are well drained are ideal for guava production. 238

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 2.2.9 Granadilla 2.2.10 Macadamia Granadillas enjoy mild temperatures all year. Macadamias require temperatures ranging from They are susceptible to severe frost (especially 16 to 25°C. Although the trees may withstand the purple granadilla). They should be grown on temperatures as low as 3°C, they should not be cool slopes in hot locations, and in cool areas on considered frost resistant. warm northern slopes. The average maximum Most soil types are appropriate for macadamia monthly temperature should not be higher cultivation, as long as they are well drained and than 29°C, and the lowest temperature should do not have any limiting layers in the top 1 m not be lower than 5°C. Granadillas require high of the soil. Clay soils with poor drainage are relative humidity and evenly distributed rainfall unsuitable. of at least 1200 mm per year (irrigation can The altitude above sea level has an impact on supplement low rainfall). nut quality and output. It is commonly known that better crack outs (kernel as a percentage of dry nut in shell weight) are typically attained at lower altitudes due to the nuts developing thinner shells in warmer environments. Macadamias growing in warmer climates will have thinner shells even at low elevations. The shells of nuts from KwaZulu-North Natal's Coast are thinner than those from the colder South Coast. Plantings of macadamias in Mpumalanga and Limpopo extend from 600 to 1200 meters above sea level. However, it is likely that the climatic conditions linked with the elevations, 239

Climate-Smart Agriculture _ Training Manual Subtropical fruit production not the altitude, affect the kernel percentage. The pecan-nut tree flourishes in subtropical Moderate temperatures with considerable climates. It also thrives in climates with short, humidity appear to be optimal. When the plants cold winters and long, scorching summers. are less stressed, less energy is expended on Low temperatures, including frost, are shell formation, resulting in thinner shells. Both necessary for effective budding and flower heat and cold can cause harm to macadamia growth from June to August. The tree demands plants. high temperatures for fruit development Frost typically kills young trees, while elder trees throughout the summer months (October to usually survive. Frost damages blooms, resulting April). Trees grow in valleys and beside rivers in a reduced fruit (nut) set. Temperatures when the winter temperature is low and frost exceeding 35°C, on the other hand, become too occurs. hot and decrease photosynthesis. As a result, During the summer, the average monthly tropical and subtropical locations are more maximum temperature should be greater than suited; nevertheless, there are spots in the 28°C and lower than 23°C. The average monthly highlands that produce macadamia nuts, and minimum temperature must be higher than microclimate will be more important in these 16°C in the summer and lower than 8°C in the areas. winter. The best producing locations include 2.2.11 Pecan short, cold winters and long, hot summers, with no early or late frost and humidity levels below 55% for the most of the growth season. Because humidity is high near rivers, valleys, and low-lying regions in the subtropics, only scab-tolerant varieties should be planted. The pecan-nut tree grows best in rich, well-drained soil with a loose to medium texture. Practical activity 2 1. What subtropical fruit crops can be grown in your area? 2. What are the major limitations and challenges that producers face? 240

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 3 MITIGATION & ADAPTATION Agricultural producers have always had to deal tolerance to adverse environmental conditions with changing weather patterns. The weather and stresses (e.g., high temperature, drought, might be hotter or cooler, wetter or dryer. flooding, high salt content in soil, pest and Farmers have learned to adapt, and despite disease resistance) are used to reduce risk. decreased yields, they are still able to produce Conservation agriculture, organic agriculture, and market. Unusual weather patterns are and risk-coping production systems that include becoming more common and less predictable. crop rotations, agroforestry, crop-livestock Significant weather conditions (e.g., extreme associations, crop-fish systems, and the use of drought, high temperatures, hailstorms) can hedges, vegetative buffer strips, and other farm result in crop failure. landscaping measures are among the areas to Climate change is causing changes that may have be investigated. an impact on agriculture productivity. Rainfall is Conservation agriculture, organic agriculture, becoming more unpredictable; in some areas, and risk-coping production systems that include it is decreasing, while in others, it is increasing crop rotations, agroforestry, crop-livestock in frequency and severity. Farmers must now associations, crop-fish systems, and the use of adapt to climatic changes that will affect the hedges, vegetative buffer strips, and other farm way they farm irreversibly, rather than only landscaping measures are among the areas to dealing with short-term weather disasters like be investigated. droughts, floods, heat waves, and cold spells. Planting trees is one of the most effective and Farmers urgently need to better understand the acotmsto-esfpfehcetrieveamndeaandsdorefsrseinmgotvhinegcCliOm2aftreomisstuhee. predicted consequences of climate change in As trees grow, they absorb and store carbon order to become more inventive and produce dioxide emissions that contribute to global enough to feed themselves and the ever-growing warming. According to new study, a global local, regional, and worldwide populations. planting program might eliminate two-thirds of Their additional task is to do so in ways that all human-caused emissions in the atmosphere safeguard the environment, particularly soil today. and water, and reduce agriculture's impact to Fruit tree production is a medium to long-term climate change. investment with few modifications possible As a counter-measure to the predicted after the crop is established. Fruit tree growth consequences of climate change, it is critical periods are typically in the 5–10-year range, that all agricultural operations contain with optimum yield occurring several years modifications to reduce these effects on following planting. As a result, once the crop productivity. Biodiversity, in all of its forms, has been established, the types utilised and improves resistance to changing environmental cropping regions cannot be readily altered, as circumstances and stressors. The integrated this would result in economic losses for farmers. farm system, which employs indigenous and locally adapted species, as well as multi crop systems in which crops and cultivars with 241

Climate-Smart Agriculture _ Training Manual Subtropical fruit production Targeting existing types in appropriate and benefit of being more resistant to changes in acceptable production settings is thus important weather conditions, save at key seasons such as for every fruit tree grower, both now and in the flowering or fruit filling. future. Fruit trees, on the other hand, have the Table 2 Comparing current agricultural practices and Climate-Smart Agriculture. Source: Adapted from FAO, 2013. Land Current agricultural practices Climate-Smart Agriculture Expansion of agricultural land by • Instead than expanding into new Natural resources deforesting and turning grasslands regions, intensify usage of current to crops. locations Varieties and • Instead of deforesting new regions, breeds Make the best use of natural increase cultivable land area by Inputs resources - the land, water, forests, rehabilitating damaged land and soils needed in industry - while Energy use giving little consideration to their Natural resources must be restored, Production and long-term sustainability. conserved, and used in a sustainable marketing Rely on a few crops, as well as a few manner. high-yielding kinds and breeds. To sustain production, improve yields, • Increase the use of fertiliser, and assure stability in the face of climatic insecticides, and herbicides change, use a combination of old and new, regionally suited types and breeds. • Improve agrochemical efficiency • Integrated management techniques Use farm machinery that typically can be used to control pests and runs on fossil fuels, such as tractors weeds and diesel pumps. To increase efficiency, make use • Compost, manure, and green manure of specialised manufacturing and should all be used marketing. • Rotate crops with legumes to fix nitrogen and decrease the need for synthetic fertilisers Use energy-saving technologies such as solar power and biofuels. Diversify your manufacturing and marketing to increase stability and lower risk. 242

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 3.1 ORCHARD MANAGEMENT unproductive trees or extremely old and less productive trees, irrigate trees that have a strong 3.1.1 Water availability harvest or the potential to generate excellent Drought is now affecting several regions of yields during the early stages of a drought. As South Africa, including numerous orchards. the drought worsens, more extreme measures Irrigation of subtropical fruit trees is one of will be required. Older and less productive the most essential parts of management for a orchards should not be watered and should be successful yield. Over and under watering are stumped. both harmful to the tree and a waste of water Water consumption can be reduced by lowering and money. or turning off all sprinklers on trees that are old, When drought circumstances prevail, the sick, or damaged. Another alternative is to shut producer strains to produce a crop while also off the water supply to the boundary trees, ensuring the life of the trees. Proper irrigation is which are more stressed as a result of the wind. so critical to the producer. These trees are excellent pollinators and can be With this declining production commodity in regarded for high functioning types. They can mind, a few critical techniques are presented. then be irrigated at a low volume to preserve The producer should consider the various blooming but not fruit set. options and plan accordingly. However, there Mulching around trees reduces evaporation, is no alternative for water, and the amount of improves moisture retention, and helps to water available will ultimately determine the manage weeds. Younger trees, in particular, action. should be mulched to ensure their survival. 3.1.1.1 Irrigation depth Pruning, thinning, and stumping procedures The depth of irrigation is governed by the depth should only be considered in extreme drought of the soil and the depth of the roots. Under situations when the amount of water and other typical conditions, the majority of the roots options, such as lengthening the irrigation occur to a depth of 600 mm. A farmer should schedule, are insufficient to bring orchards check the root depth of his orchards. Wetting through. Trees that are more than a decade the region below the root zone is a waste of old should be trimmed or thinned back. Heavy water. It is also reasonable that if 900 mm of trimming will minimize canopy area, resulting soil can be watered instead of 600 mm, the soil in less water loss and use. However, due to water storage would grow by about 50%. the deep root systems of some fruits, such as avocado, thinning 50% of the trees would only 3.1.2 Orchard considerations to take into lower water demands by 25-30%. account Stumping should be used only as a last option. Examine each orchard's output history. This This will halt production of the trees for roughly will show which orchards should be eliminated three years. For this reason, entire portions might if required. Different tactics will be used at the be evaluated. The advantage of this approach is start of a drought crisis. Rather than young that it enables for the trees to be top-worked to new and better-adapted cultivars. After three years, when the trees that were initially 243

Climate-Smart Agriculture _ Training Manual Subtropical fruit production stumped begin to produce, the other trees can well before the tree starts to wilt. Most be stumped. Irrigation must be decreased for all subtropical fruit trees require irrigation from stumped trees. Normal pruning and stumping early blooming till after fruit set. Irrigation techniques, such as shading exposed branches should be done especially the day before bad from direct sunlight, should be followed. weather, such as strong winds, is predicted The use of covered cultivation for tree fruit during this time period. Furthermore, if the crops, particularly the use of shade netting, bloom is light, it implies minimal yields and is becoming more common. Protected should be considered stumping the trees. horticulture has several advantages, particularly Government assistance has aided farmers in in the face of harsh weather conditions. surviving protracted droughts and, to some Protection may provide benefits such as extent, has safeguarded the productive reduced air temperature, sun irradiance, wind capacity of the country's agricultural sectors. speed, and hail protection. Hailstorms, extreme However, due to climate change, South Africa as sun radiation, and high wind speeds may all a country must reconsider how it planned for have a significant impact on yields and fruit and responds to drought in the future. South quality. Additional research is needed to assess Africa must better plan for droughts in order the impact of shade netting on crop quality and to mitigate their effects. Even if the present production in subtropical crops. drought ends, others will follow. Investing in 3.1.2.1 Critical growth stages more drought-resistant practices, for example, If water becomes a key issue after all other decreases the demand for drought relief today variables have been considered, tree phenology and in the future. Moving the emphasis from should be closely studied to predict essential drought alleviation to drought management and watering periods. Yield reductions will occur preparedness will ultimately be more successful in the long run. Figure 3 Citrus trees planted under shade netting. 244

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 3.1.3 Cultivar selection 3.1.4 Diversifying crops Using more appropriate and/or robust varieties/ By introducing new varieties of crops and cultivars will be one of the adaptation methods cultivating new species, we can improve plant to reduce the impact of climate change. productivity, quality, health, and nutritional Adoption of new kinds, an often mentioned value, as well as improve crop resistance to alternative for climate change adaptation, diseases, pests, and environmental stress. This happens considerably more slowly in perennial might involve introducing new crops or cropping fruit crops than in annual crops. Perennial systems into agricultural production while agriculture's extended time horizon poses taking into consideration various returns from unique problems in a changing environment. value-added products and market prospects. During the lifetime of an orchard, previously favorable areas may become unfavourable. 3.2 CONSERVATION AGRICULTURE By choosing the best varieties for the current climate, one runs the risk of selecting a variety Conservation agriculture is an integrated which will not suit future climates. Thus, while agricultural strategy that attempts to use adjustments such as planting new cultivars and soil, water, biological resources, and natural relocating to different regions may decrease processes more efficiently through improved long-term consequences, short-term losses soil, water, and plant nutrient management. may occur. Farmers will require crop varieties The essential concepts include guaranteeing the that are more resistant to stressors like heat, as recycling and regeneration of soil nutrients and well as photo and thermal-insensitive cultivars, organic matter, as well as making the most use in this context. of rainfall by retaining and better using biomass, Considering that tree species differ in their moisture, and nutrients. One important capacity to adapt to climatic circumstances and component is preserving a permanent soil their sensitivity to risks, fruit crop selection and cover, which requires zero or little tillage. breeding will take climate forecasts into account, Conservation agriculture, low or zero tillage, with hybridization and clonal selection offering and the preservation of permanent soil cover the possibility to respond to environmental can enhance soil organic matter and mitigate changes. Because future precipitation may be the effects of flooding, erosion, drought, heavy more irregular, cultivar and species selection rain, and winds. criteria will need to focus more on water efficiency, drought tolerance, and disease and pest resistance. Fruit breeders, researchers, and other users can improve yields in the context of climate change by using genetic diversity acquired from diverse agro-climatic situations and conserved ex situ and on farm. 245

Climate-Smart Agriculture _ Training Manual Subtropical fruit production While heavy soil tillage lowers soil organic matter drawback of single crop production companies by aerobic mineralization, moderate tillage and is that they are susceptible to a high level of risk the maintenance of a permanent soil cover and uncertainty due to the farmers' seasonal, (through crops, crop residues, or cover crops, irregular, and uncertain revenue. as well as the use of diverse crop rotations) Meeting farmers' requirements in order for increases soil organic matter. A no- or low- them to implement an integrated farm system tilled soil preserves soil structure for fauna and necessitates a new rethinking of agricultural associated macrospores (earthworms, termites, education, research, and extension. An and root channels) to act as drainage routes for integrated farm is a living system with dynamic excess water. Surface mulching protects soil interactions between its many components. from high temperatures and evaporation losses, The integrated farm aspires to be a closed and it can lower crop water requirements by up system, capable of operating eternally with to 30%. minimal outside inputs and little or no waste, Soil erosion and water loss through runoff and is fueled by what industrial farming deems are entirely or significantly reduced as a waste, particularly manure. consequence of vegetation and residues As a result, the integrated farming system is covering the soil, crop production is more stable a low input system that seeks to optimise the and less vulnerable to weather fluctuations, and management and use of internal (on-farm) better yields may be produced. Not only does production inputs such as manure, compost, employing these methods increase and, more cover crops, and management practices while importantly, stabilize output, but it also lowers minimizing the use of off-farm resources production costs. Conservation agriculture helps such as chemical fertilisers, herbicides, and to save the environment while both increasing pesticides wherever and whenever feasible and sustaining agricultural production. and practicable to lower production costs. This The application of conservation Agriculture has the potential to enhance both short-term and minimal or zero tillage, as well as the and long-term profitability. In the long run, the preservation of permanent soil cover, can agricultural system is thus more economically, enhance soil organic matter and mitigate the socially, and environmentally sustainable. effects of flooding, erosion, drought, heavy rain, This does not mean no input is made, for and winds. example that soil nutrients are not being maintained or that weeds are not controlled. It 3.3 INTEGRATED FARMING just means most inputs can be made from on- SYSTEMS farm resources and few have to be purchased from outside. kept up by putting more focus on Integrated farming balances food production, cultural practices, Integrated Pest Management profitability, safety, animal welfare, social (IPM), and the use of on-farm resources and responsibility and environmental care. management. Integrated farming aims to strengthen Thus, integrated farming is a common-sense agricultural production's beneficial affects (whole-system management) strategy that while minimizing its negative effects. The main 246

Climate-Smart Agriculture _ Training Manual Subtropical fruit production integrates ecological care of a diversified and healthy environment with agricultural economic demands to assure a continuous supply of nutritious and readily available food. It is not prescriptive because it is a dynamic concept: it must be adaptable in order to be applicable on any farm, and it must be open to change and technology improvements. 3.3.1 Intercropping One of the most difficult issues for farmers today is increasing production per hectare in a sustainable manner. Intercropping is essentially a multiple cropping practice in which two or more crops are grown on the same land. The fundamental objective of intercropping is to maximize the potential yield of a certain field by maximizing the potential of the resources available at a given moment. Intercropping is the cultivation of two or more crops in the same field at the same time throughout the growing season. It is the implementation of ecological concepts like as variety, crop interaction, and other natural regulatory systems in practice. The improvement in production per unit of land is one of the most important reasons to cultivate two or more crops together. Intercropping offers several benefits linked to the complementary use of natural resources by the component crops, which results in higher and more consistent yields, improved nutrient recycling in the soil, better control of weeds, pests, and diseases, and enhanced biodiversity. 247

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 3.3.1.1 Advantages of intercropping Mulching is the process of covering the soil • Increased crop yields per unit area with a layer of material. In the summer, it keeps the roots cold, and in the winter, it keeps them • Improved soil fertility by leguminous warm. Leave agricultural leftovers on the land intercrops (nitrogen fixing) rather than removing it. • Reduced soil erosion • Lowered soil surface evaporation Mulch significantly lowers the amount of weeds • Reduced weed infestation while also retaining soil moisture. Any old plant • Intercropping trees with plants can also material can be used, with the exception of help repel pests since many herbs have weeds that have already set seed, which will insect repellent qualities result in an increase in weed population. To ensure that the soil is thoroughly covered, mulch 3.3.1.2 Disadvantages of intercropping is placed around the trees and in the vegetable row. The mulch enhances the soil structure and Intercropping is not always appropriate for a fertility as it decomposes. To provide a continual mechanized agricultural system because it is: soil cover, more mulch should be spread when • Time consuming: It necessitates greater the previous mulch breaks down. attention and, as a result, more intense, skilled management 3.3.2.1 Types of mulch • Planting, weeding, and harvesting efficiency is lowered, which may increase labor • Organic residue – grass clippings, leaves, expenses in these activities hay, straw, comfrey, shredded bark, entire • Good planning is essential, and this involves bark nuggets, sawdust, shells, woodchips, careful cultivar selection, correct spacing, shredded newspaper, cardboard, wool, and and so forth cow dung are all examples of organic waste. • Green mulch – also called living mulch. Green weeds or other plants used to cover 3.3.2 Mulching bare soil and supply nutrients (fertiliser) to important crops. • Wood chips are a by-product of tree pruning and are used to dispose of bulky trash. • Leaves – the leaves of deciduous trees that shed their foliage in the fall. They are frequently chopped or shredded before application since they are dry and fly around in the wind. • Straw – is made from the discarded stems of harvested grain harvests. • Grass clippings - originate from mowed lawns and are occasionally collected and utilised as mulch elsewhere. • Compost – this should be fully composted material to avoid possible phytotoxicity problems, and weed seed must have been eliminated, otherwise the mulch will 248 actually produce a weed cover.

Climate-Smart Agriculture _ Training Manual Subtropical fruit production 3.3.2.2 Advantages of mulching As a result of global warming and climate change, • Mulching increases soil nutrient and water the relative efficacy of pest management retention approaches such as host-plant resistance, • Encourages beneficial soil microbial activity natural enemies, bio-pesticides, and synthetic • Suppresses weed growth insecticides is expected to vary. Pests currently • Mulching helps to minimize evaporation account for up to 40% of the world's food supply; • Mulching also aids in the retention of consequently, minimizing pest effect is critical moisture, the prevention of soil erosion, to ensuring food security, cutting inputs, and the control of weeds, and the addition of lowering greenhouse gas emissions. Although nutrients to the soil certain climate change impacts may be helpful, research shows that pest issues will become 3.3.2.3 Disadvantages of mulching more unpredictable and amplitude would rise • Heavy mulching over a long period of time (Gregory et al., 2009). Forecasting the impacts may result in soil buildup over the crown of climate change on pests is, however, difficult area of plants due to the complex interplay of increasing • Mulching can create a safe haven for acltimmoastipchreergicimeCsO, 2andcoinnccreenatsreadtiofnres,quesnhcifytinogr cutworms and other pest insects intensity of extreme weather events (Heeb et • The high cost of some materials can be an al, 2019). impediment to large-scale mulching IPM is a modern, sustainable strategy that • Nitrogen deficiency can arise when sawdust supports the use of natural pest management and woodchips are used as mulch mechanisms in order to cultivate healthy crops with the least amount of disruption to 3.4 INTEGRATED PEST agroecosystems and hazards to human health MANAGEMENT and the environment. Key pillars of IPM include: Climate change is having an impact on the biology, distribution, and outbreak of pests • Pest identification (insects, diseases, and weeds), as well as the • Monitoring and assessing existing and possibility for new pests across all land uses and landscapes. Climate change and global warming potential pest threats will have a massive effect on the geographical • Gaining detailed knowledge of pest threats distribution and population dynamics of insect pests, insect-host plant interactions, the activity and the various management options and abundance of natural enemies, and the available to them efficiency of crop protection technologies. Insect • Preventing the establishment of these pests pests that are now restricted to tropical and • Implementing interventions against any subtropical regions may migrate to temperate pests that emerge regions when their host plants' production • Evaluating the effectiveness of pest threat areas alter. management to improve it where necessary 249