Climate-smart crop production practices and technologies
This chapter presents management practices and technologies for climate change adaptation and mitigation. It covers practices with an explicit focus on adaptation to specific climatic stressors, and practices that simultaneously reduce production risks and lower greenhouse gas emissions. Most of these practices prevent soil damage that releases carbon and water into the atmosphere; promote soil and water conservation; and increase productivity.
Table B1.1 presents the climate-smart management practices for different crop systems that can help farmers adapt to specific climate change risks and/or mitigate these risks.
In some cases, radical changes, such as shifting to an entirely different agricultural production system, may be needed to adapt to new climate conditions. The important role policies and institutions play in supporting climate-smart strategies is dealt with in chapter B1-4.
Use of quality seeds and planting materials of well-adapted crops and varieties
An indispensable input for climate-smart crop production is quality seeds and planting materials of well-adapted varieties. It is impossible to harvest good crops with bad seeds (FAO, 2011).
National, regional and international plant breeding efforts usually involve multilocational trials and seek to develop crop varieties that are resistant to climate-related phenomena and more efficient in their use of resources to reduce their impact on the agricultural ecosystem and the wider environment. Resistance to drought, salinity and flooding are the most common climate-related traits for which crop varieties are bred. Other more location-specific factors include higher frequencies of frosts at the seedling and/or pollination stages; high temperatures at the grain-filling stage; heavy rains that compress the soil; and alternate light rains and hot temperatures that stimulate seed germination but prevent the establishment of seedlings.
The development, official release and registration of well-adapted crop varieties are the steps taken toward the ultimate goal of ensuring farmers have access to quality seeds and planting materials. However, achieving this ultimate goal also requires a reliable mechanism for delivering the seeds of the most suitable varieties to farmers. Farmers obtain seeds from formal systems and/or informal systems.
Formal seed systems are organized and underpinned by statutory requirements that ensure the seeds that farmers use pass through standardized quality assurance mechanisms. Delivering the improved varieties to farmers through formal systems is relatively straightforward. But, farmers, especially in developing countries, also obtain seeds from multiple unregulated sources. These sources can include saving seeds from their own harvests, purchasing seeds from local markets and exchanging seeds with family members and neighbours. This way of obtaining seeds constitutes the informal system or farmers’ seed system. Informal systems predominate in developing countries where crop production systems are the most vulnerable to extreme weather events. For such production systems, which are typically characterized by low-input agriculture, small-scale holdings and limited market engagement, it is particularly important to support community-based seed production and distribution channels. In parts of the world where climate change is expected to have the greatest impact, most of the seeds sourced through community-based delivery systems are important food security crops. These crops include beans, peanuts, cassava, cowpeas, open pollinated maize, sweet potato and yams. Small- and medium-scale enterprises are effective means for ensuring that quality seeds of the most suitable varieties are available to small-scale farmers and are within easy reach in their communities.
Ideally, irrespective of delivery system, seeds that are meant to be sold or otherwise distributed for planting must have their quality assured. There are different options for achieving quality assurance. In the formal system, there is official control and inspection, usually by government agencies or accredited entities such as farmers’ associations and seed companies, which result in certified seeds. A less demanding mechanism is the Quality Declared Seeds and Quality Declared Planting Materials systems, developed under the auspices of FAO. These options ensure that costs associated with standard certification processes do not hinder the availability of quality seeds.
Box B1.1 describes the components of a system that provides farmers with affordable quality seeds and planting materials of well-adapted crop varieties in a timely manner. Mechanisms that facilitate seed trade between countries are discussed in Chapter B1-5.
Box B1.1 Seed Systems
A seed system encompasses all the stakeholders (individuals, organizations and institutions) that are involved in the development and dissemination of crop varieties; the production, multiplication, processing, storage, distribution and marketing of seeds and related practices and processes; and the prevailing policies, regulations and laws. The following components of a seed delivery system are critical in formulating for climate-smart agriculture strategies.
Conservation of plant genetic resources for food and agriculture
Conserved and characterized plant genetic resources for food and agriculture need to be available for use as ‘raw materials’ for the development of varieties that are resistant to abiotic and biotic stresses. To address the challenges posed by climate change, there is the increasingly urgent need for the investment of greater resources and efforts in safeguarding the widest possible diversity of plant genetic resources for food and agriculture in their natural habitats in situ, on farms and in genebanks ex situ. The diversity of crop wild relatives, an important source of heritable traits for crop improvement, could be eroded as their natural habitats are lost due to climate change. The role of plant genetic resources in climate-smart agriculture is addressed in more detail in module B8.
Crop varietal development
Plant breeders must develop an increasingly diverse portfolio of varieties of an extensive range of crops in order to adapt production systems to climate change. Generating novel varieties will most often depend on obtaining heritable variations, especially from the non-adapted materials, including crop wild relatives, that are not usually used by breeders. This will involve institutionalizing and improving capacities for pre-breeding activities in which germplasm curators and breeders work together to identify the carriers of desirable traits, evaluate these putative parents and cross promising ones with elite lines to generate intermediate breeding materials. It may also be necessary to create novel variations that are absent in the gene pool through induced mutations and the application of biotechnological procedures, such as genetic engineering and genome editing. High-throughput genotyping and phenotyping platforms are being used more and more to make the processes for developing crop varieties, including pre-breeding, more efficient.
In farmer participatory plant breeding, farmers and plant breeders collaborate in crop varietal development. Because the perspectives of the farmers contribute to the decisions about which varieties are proposed for official release and registration, participatory plant breeding is an effective way to achieve demand-driven crop improvements for adaptation to climate change, especially in developing countries.
Seed production and delivery
An effective agricultural extension system and a responsive seed delivery system are needed to enable farmers to access quality seeds and planting materials of well-adapted crop varieties at affordable prices and in a timely manner.
- Farmers are more willing to use a new variety when they have trusted information and are confident the new variety will meet their needs. The extension system is particularly important to generate data about the performance of varieties. For instance, the FAO Farmer Field Schools approach (addressed extensively in module C2) has proven particularly effective in using demonstration plots to showcase the advantages of well-adapted crop varieties to communities of small-scale farmers.
- A responsive seed delivery system requires national policies, strategies, regulations and legal frameworks that cater to both the informal and formal seed systems and recognize their generally complementary roles.
- Climate change is expected to increase the frequency and intensity of extreme weather events, which will trigger crises that threaten the immediate food security of large populations and possibly spark famines. These events will also affect farmers’ ability to obtain quality seeds and planting materials, which will jeopardize the success of subsequent cropping seasons. A seed security assessment is a way to determine the availability of seeds, their accessibility to farmers, and their quality and their compatibility with farmers’ varietal preferences and production systems. It is a means for identifying the most suitable responses to the lack of seeds without hindering the development of the seed sector. Seed security assessments consider formal and informal sources of seeds and the functioning of the entire value chain to identify the main constraints farmers face in obtaining the seeds they need. The outcomes of the assessments guide the next course of action, which may be immediate interventions, such as the direct distribution of seeds to farmers, support to seed markets, cash transfers, or longer-term developmental activities. Two useful tools for ensuring that farmers have access to quality seeds after a crisis are the Seeds in emergencies: a technical handbook and the Practitioner's Guide for Seed Security Assessments.
Source: Authors
Biodiversity management
Growing “a genetically diverse portfolio of improved crop varieties, suited to a range of agro-ecosystems and farming practices, and resilient to climate change” is a validated means for enhancing the resilience of production systems (FAO, 2011). When confronting abiotic changes (e.g. shifting rainfall and temperature patterns) and biotic disturbances (e.g. pest infestations), the level of existing biodiversity (both functionalxii and responsexiii diversity) can make the difference between a stressed agricultural ecosystem and a resilient one. Biodiversity management is dealt with in module B8.
All major grain crops, including maize, wheat, rice, and most other crops are often grown in monoculture systemsxiv that require significant investments in pesticides and herbicides. In nature, one species (and especially not one crop variety) is never found alone in one field. When agricultural ecosystems are simplified, whole functional groups of species are removed, and their capacity to respond to changes and provide ecosystem services is compromised (Folke, 2006). In a cropping system, greater diversity of crops and other living organisms is an important criterion for ensuring farm resilience, economic stability and profitability. This diversity is especially important in a climate-smart approach because it contributes to pest and disease management, which has direct effect on yields and revenues and can be very costly and labour-intensive if external inputs need to be used. Enhancing on-farm biodiversityxv and integrating production (see module B5) also provides other environmental services, including pollination, that are essential to farmers and society as a whole. The level of biodiversity in the agricultural ecosystem influences the interactions of plant, animal, microbial species (above and below ground) at the landscape level. A landscape approach to climate-smart agriculture is addressed in module A3. At the territorial level, increasing the sustainable use of agricultural biodiversity in terms of both production and consumption in landscapes and diets offers great potential to shape rural and urban (city-region) food systems in ways that can safeguard the future food and nutrition security of expanding urban populations. Territorially-based climate-smart food systems are addressed in module B10.
The diversification of crop systems can take many forms, involving different crop species and/or varieties (intra- and/or inter-specific diversification), different spatial scales (landscape, farm, individual fields and/or crop) and different time frames.
Integrating multipurpose crop varieties, whose biomass can be used in a range of combinations for food, biofuel, feed, and/or fiber, can improve the functional and productive management on the farm and be climate-smart. Examples of multifunctional crops include living fences that can provide food and feed and serve as windbreaks. The use of perennial species as multipurpose crops is discussed in chapter B1-3.1.
In individual fields, there are several ways in which the genetic diversity of crops can be enhanced. These practices all require that the dates and rates of seeding be tested locally to ascertain the most suitable combinations of crops, crop density and sequencing matter (Chapter B1-4.1). This is needed to ensure the crops selected are appropriate for the specific conditions of each farm system and do not compete for nutrients, water and light. These options include:
- Different crop varieties of the same species can be grown in mixtures as one crop (varietal mixtures). For example, growing a mix of varieties with the same growing length that can be planted and harvested at the same time, but that respond differently to different water regimes, is a strategy to cope with the unpredictable onset of the rainy season and increase the stability of yields.
- Different crop species can be grown:
- simultaneously in the same surface area as mixtures or planting a second crop in the first crop (relay cropping);
- simultaneously in different spaces (intercropping); or
- planting a different crop after the previous crop has been harvested (crop rotations).
- Livestock and aquaculture can be integrated into crop systems. This subject is dealt with in module B5.
Integrated Pest Management
Climate change will affect the spread and establishment of a wide range of insect pests, diseases and weeds. This phenomenon will be in large part a consequence of changes in the distribution and health of naturally occurring host plants and crops, natural enemies, and the adaptive changes in farm management (see chapter B1-1.2). With the increasing globalization of the trade and exchange of germplasm, these changes will provide new challenges for pest management.
Integrated pest management is an ecosystem approach to crop production and protection. It is based on the careful consideration of all available pest management techniques. Integrated pest management involves the use of appropriate measures to discourage the development of pest populations and keep pesticides and other interventions to levels that are economically justified; reduce or minimize risks to human health and the environment; and disrupt as little as possible the agricultural ecosystem. The ability to make good decisions in the field is crucial for effective integrated pest management. The principles of FAO Integrated Pest Management approach include growing healthy crops; understanding ecological processes in the fields and encouraging natural pest management mechanisms that maintain ecological balances among populations of pests and their natural enemies (predators, parasitoids, antagonists); observing fields regularly; and building farmers' capacity and understanding of ecological needs so that they are empowered to take the best pest management decisions in their own fields. Chapter B1-2 on biodiversity management covers the role that diversified crop systems can play in enhancing the resilience of cropping systems and providing ecological insurance against crop failures. Chapter B1-3 on sustainable soil and land management addresses the links between soil management, integrated pest management and the impacts of climate change. In tilled soils, for example, when the soil surface remains exposed for parts of the season (e.g. between the harvest of one crop and the establishment of the next) and in specific spaces (e.g. between rows or beds until the crop has closed canopy), empty ecological niches are formed where the soil is unoccupied and moisture and nutrients are not utilized. In areas where humidity is guaranteed throughout the year, this is the ideal environment for annual weeds to proliferate. Controlling them requires energy, costly tillage, pulling, mowing and/or herbicides. In environments where the primary productivity is low, the exposed soil lead to losses in soil organic matter and biodiversity, increased compaction and greater erosion rates. Crops growing in these soils are less resilient and climate change affects them more (Chapter B1-1.2).
Integrated pest management is valid in a variety of different and evolving farming conditions. Independently of how climate change will affect agricultural ecosystems, farmers who understand integrated pest management principles will be better equipped to cope with the effects of climate change and develop sound and location-specific adaptation strategies (Allara et al., 2012). This is why, on farms and in farming communities, FAO integrated pest management programmes are often implemented through Farmer Field Schools, which facilitate learning by doing and experimentation of different management options by farmers (see module C2). Specific details on the control of the parasitic weed Striga is presented in Box B1.2.
As the climate changes, national regulatory, policy and institutional frameworks must be strengthened to enable the adoption of integrated pest management practices on farms and in rural communities. In particular, frameworks should support farmer training in integrated pest management; maintain the surveillance systems, including those used in community groups, that are used to detect and report changes in the behaviours of pests and natural enemies; develop appropriate quarantine procedures to prevent the entry and establishment of plant pests; and formulate appropriate management strategies to respond to potential outbreaks. Other important elements of any strategy to promote a shift to resilient crop production systems include phytosanitary frameworks and measures that can facilitate the creation of markets for sustainable products; and the transparent collaboration among policy makers, industries and farmers on the national registration processes for the most appropriate pesticides to a climate-smart approach (FAO & INRA, 2016).
Regionally and internationally, common regulations and strategic frameworks (e.g. the International Plant Protection Convention (IPPC) and the FAO International code of conduct on Pesticide Management to limit the impact of invasive species and the unregulated use of chemical pesticides. However, pest management systems would benefit from more coordinated actions to prevent crises associated with transboundary pests, major pest outbreaks and climate change. Greater coordination in this area can be achieved by building new partnerships and alliances that can connect stakeholders, including farmers, at local, national and regional levels, and enable them to address common challenges (Allara et al., 2012).
The enabling environment for climate-smart crop production and protection is addressed in Chapter B1-4.
Further information on integrated pest management can be found at the following web sites: FAO Plant Production and Protection Division: Integrated Pest Management; Vegetable Integrated Pest Management Asia programme; Integrated Production and Pest Management Programme in Africa.
Box B1.2 The influence of climate change on Striga distribution and management
The genus Striga is a member of the family Orobanchaceae, which includes several other parasitic plants. Striga species are root parasitic weeds that siphons of water and nutrients from their hosts and substantially reduce their growth. Striga, which is native to the grasslands of sub-Saharan Africa, includes about 40 species with several different strains and some new variants (Fischer, et al., 2011). The physiological requirements of Striga have checked its spread outside the tropics, but climate change projections suggest that some species may spread, with some even reaching temperate areas (Mohamed et al., 2007; Cotter et al., 2012).
While the majority of Striga species have remained in the wild grassland ecosystems in which they evolved, a few have adapted to agricultural ecosystems and have become weeds (FAO, 2003). They mostly affect cereal crops including sorghum, millets, maize and upland rice. Striga gesnerioides is a parasite of dicotyledons such as cow pea (Vigna unguiculata), which is a major source of plant protein in sub-Saharan Africa. The most economically important parasitic weeds affecting production of cereals are Striga hermonthica, across much of northern tropical Africa, and Striga asiatica in central and southern Africa and across Asia and isolated regions of Australia. These species also harm sugarcane production. On average, Striga species infest as much as 40 million hectares of farmland in sub-Saharan Africa, can cause yield losses of up to 100 percent (IAASTD, 2009) and an average reduction in productivity of 12 to 25 percent. In Africa, it affects the livelihoods of about 300 million people (FAO, 2003). Projections from the last comprehensive study (Sauerborn, 1991) estimate annual cereal losses to Striga at about 4.1 million metric tonnes at a cost of USD 12.8 billion (Ejeta, 2007).
Farmers use a variety of Striga control methods (organic manure, crop rotation, fallow), but the results can often be unsatisfactory. In fact, the problem continues to worsen due to the high fecundity of the parasite and mismanagement that have favoured the build-up of prohibitively large Striga populations (Babiker, 2007). The monoculture of cereals, in which farmers use continuous cropping and follow poor agronomic practices, such as a lack of crop rotations, are conducive for the build up of Striga populations. This is particularly true in agricultural ecosystems where high human population densities put strong pressures on arable land (Eplee, 1992).
The solution to Striga infestation resides in breaking its life cycle. Effective Striga management options should be built around three pillars: (i) preventing the production of new Striga seeds; (ii) decreasing the soil seed bank of Striga; and (iii) improving soil fertility.
Striga management projects that take into account those three pillars have been implemented in Benin, Burkina Faso, Mali, Niger and Senegal to compare different management methods to alleviate the problem (FAO, 2008b). Rotation with non-host crops, particularly legumes (e.g mucuna) substantially reduces Striga infestation and improves soil fertility.
Source: Adapted from Ejeta, G. and Buttler, L.G. 1993.
Improved water use and management
Where water is a limiting factor, improving water management can be achieved through measures that conserve soil and water; and/or with deficit irrigation that can maximize crop yields per volume of water applied; and/or more efficient irrigation technologies that can reduce unproductive evaporation losses. Water management for climate-smart agriculture is dealt with in greater detail in module B6.
Achieving greater efficiency in irrigation often involves additional energy costs (see module B9). For this reason, the expansion of irrigation needs to be accompanied by appropriate energy technologies (e.g. solar powered pumps).
Strategies for changing agricultural water management and governance must be done by integrating a water balance analysis into decision-making processes. Water balance assessments, both at field level and at the catchment level, are necessary to understand the repercussions that changes in water use for agriculture will have on the hydrological cycle. For example, in upstream areas, the introduction of rainwater harvesting techniques on a large scale may affect ground water recharge rates and return flows and cause adverse effects for downstream water users.
Sustainable soil and land management for increased crop productivity
Sustainable soil and land management are discussed in detail in module B7, and are also addressed in module A3 on integrated landscape management.
At the landscape level, reducing land-use change by carefully limiting the need to expand cropland and grazing land can reduce emissions and increase the capacity of the soil to store carbon.
At the field level, increasing productivity allows to grow more from the land already under production. This eliminates the need to open new land for agriculture and helps reduce the emissions associated with agricultural expansion. In this chapter, the focus is on agronomic management for increasing crop productivity and improving the efficiency in the use of resources as a way of addressing climate change. The most cost-effective management strategies for sustainable intensification of crop production involve achieving a balanced cycling of nutrients through the production system and protecting the soil on the field. Nutrient cycling refers to the movement and exchange of organic and inorganic matter into the production of crops and it is dealt with in Box B7.3.
Soil protection can be achieved by practicing direct seeding in combination with the sustainable management of crop residues and within a broader framework of integrated soil fertility management. Box B1.3 provides a useful reference to optimize the management of crop residues and the decisions that influence their composition (i.e. the types of crop grown in rotation) and their decomposition (i.e. the conservation on the soil surface as opposed to its incorporation into the soil).
Box B1.3 Crop residue management for soil carbon conservation and sequestration
Carbon accumulates in the soil when the nitrogen input (i.e. from nitrogen fixation, organic matter restitutions or fertilizers) is higher than the nitrogen exported with harvested produce and lost through leaching or emissions in gaseous forms (Corsi et al., 2012). This box summarizes the crop management practices that regulate the composition of the residues accumulating on the soil surface, and the potential to augment soil carbon stocks.
- Effective crop rotations for carbon accumulation maintain a positive nitrogen balance. Crop residues with an average carbon-to-nitrogen ratio in range of 25 to 30 can be achieved by rotating between crops high in carbon and crops high in nitrogen. This allows the carbon to accumulate in the soil and enables the nitrogen in the decaying surface residues to be released slowly to the next crop. If the amount of nitrogen in the crop residues is too low, microorganisms use the mineral nitrogen existing in the soil (nitrogen immobilization), which reduces the amount of nitrogen available to the growing crop until (weeks) the carbon in the crop residues starts to deplete (Gál et al., 2007).
- Increasing the complexity of the crop rotations and integrating legume crops supports carbon sequestration. Active roots produce exudates and, notably in the case of legumes, favorable mycorrhizalxvi associations. The decomposition of old rooting systems adds organic matter at greater depths. Deep rooting systems are ideal for taking carbon deep into the soil, where it is less susceptible to oxidation. In agricultural ecosystems, about 80 percent of biological nitrogen fixation is achieved through the symbiotic association between legumes and the soil bacteria Rhizobia. Farmers have some scope to influence these natural processes by selecting legume species that are particularly effective at fixing nitrogen; increasing the proportion of legume and grass seed in forage mixtures; inoculating the legumes with bacteria (e.g. Rhizobia); improving crop nutrition, especially nitrogen and phosphorous; managing diseases and pests; choosing the best planting time, cropping sequence and cropping intensity; and managing the defoliation frequency of forage swards.
- Keeping the soil covered with a layer of evenly distributed crop residues with an average carbon-to-nitrogen ratio in the 25-30 range after harvest produces a positive residual fertilizer effect on the subsequent crops. The removal of crop residues (e.g. burning, black fallows) leaves only the crop's root biomass to be incorporated into the soil organic matter pool, which causes the accumulation of soil organic carbon to decline. For the same reasons, grain legumes should be harvested by cutting the plants; they should not be pulled up and uprooted.
- Mixing crop residues with soil (e.g. by disking or chiselling) may cause or accelerate the immobilization of nutrients in the soil and make them unavailable for the subsequent crop during the early part of the growing season. Crop residues mechanically incorporated into the soil decompose more quickly than those left on the soil surface, and nitrogen immobilization can occur very early in the season. Incorporating crop residues rich in readily decomposable carbon, such as residues with low carbon-to-nitrogen ratio or liquid manure, generally induces a priming effect on soil organic matter and increases carbon dioxide emissions. In contrast, when crop residues are not mixed into the soil, their composition does not affect the decay of the stable soil organic matter already present in the soil (Kuzyakov et al., 2000; Fontaine et al., 2004; Sisti et al., 2004; Fontaine, 2007).
- Using best management practices for nitrogen fertilization minimizes residual soil nitrate, which reduces nitrous oxide emissions. Best management practices for nitrogen fertilization include integrated nutrient management, and targeted applications of the precise amount of mineral fertilizer required.
- Using controlled traffic and growing crops that produce large amounts of root biomass can keep the soil from becoming compacted and improve drainage. This can help farmers avoid anaerobic soil conditions, which can increase nitrous oxide emissions and create a generally unfavorable environment for plant growth.
Source: Authors
Conservation agriculturexv is an approach that combines limiting soil disturbance to a minimum, maintaining soil cover and diversifying crop production. Although developed to reduce soil erosion and restore degraded soils, conservation agriculture provides a strategic entry point for climate change adaptation. Conservation agriculture seeks to reproduce the most stable soil ecosystem attainable in each agricultural ecosystem in order to reduce producers' reliance on external inputs for plant nutrition and pest management. Keeping the soil covered reduces moisture loss, stabilizes soil temperature, reduces erosion by water and wind, restores soil carbon through the decomposition of crop residues, and provides food for beneficial soil organisms. Rotating and diversifying crops reduces crop pests and diseases and replenishes soil nutrients. Avoiding mechanical soil tillage increases the populations of earthworms, millipedes, mites and other animals living in the soil. This microfauna takes over the task of tillage and builds soil porosity and improves soils structure. Conservation agriculture incorporates organic matter from the soil surface. The excrement from soil organisms provides stable soil aggregates and the vertical channels created by worms drain excess water. The organic matter incorporated by soil microfauna into the soil improves soil structure and water storage capacity, which in turn helps plants to survive longer during periods of drought. Because untilled soil can act as carbon sink by sequestering and storing carbon, conservation agriculture has also been recognized for its ability to mitigate climate change. Not tilling the soil also reduces the number of farm operations required for crop production, which lowers fuel consumption (Lal, 2003). The potential of conservation agriculture to bring about significant energy and fuel savings is one of the reasons why it has become a more attractive option to farmers in times of high energy costs (Doets et al., 2000). In 2013, conservation agriculture was practiced on around 157 million hectares worldwide. For more information, visit the FAO web pages on conservation agriculture and sustainable agricultural mechanization. The short video produced by World Bank provides information on the links among soil degradation, climate change and conservation agriculture.
Minimum mechanical soil disturbance is a long-term management approach to increasing the amount of carbon stored in the soil. However, the accumulation of soil organic carbon is a reversible process, and any short-term disturbances, such as the periodic tillage of land otherwise under no-tillage, will not bring about significant increases in soil organic carbon (Jarecki and Lal, 2003; Al-Kaisi et al., 2008). Although the benefits and reduce risks and costs in the future gained from improving soil health and increasing soil organic carbon accrue slowly over decades, taking action can also bring immediate financial dividends, help maintain crop productivity. When soil rebuilds, it grows and stores more oil organic matter and water, thus improving ecosystem functions and services (e.g. the control of rainfall runoff and soil erosion) that are critical for climate change adaptation and mitigation.
Sustainable mechanization
The availability of appropriate machinery to carry out sustainable crop management practices increases productivity per unit of land. It also increases efficiency in the various production and processing operations and in the production, extraction and transport of agricultural inputs, including coal and oil. Specific examples of the appropriate use of farm machinery in crop production are listed.
- Using smaller tractors, making fewer passes across the field and reducing working hours, when combined with conservation agriculture, reduce carbon dioxide emissions, minimize soil disturbance, and curtail soil erosion and degradation that are common in tillage-based crop systems.
- Tractor-operated tillage is the single most energy-consuming operation in crop production. Operating a plough is the main reason many farmers require high horse power, diesel-fueled tractors. Conservation agriculture is flexible enough to accommodate the socio-economic resources of smallholder farmers as well as large-scale farming operations. Minimum soil disturbance can be achieved through digging sticks, jab planters, or mechanized direct seeders specifically developed to drill the seed through a vegetative layer. With the introduction of conservation agriculture, the machinery park of mechanized farms changes to equipment that requires less pulling power than a plough does. This means that smaller tractors, including two-wheel tractors, can be used; less fuel is consumed; work time is reduced; and the depreciation rates of equipment is slower. All of this leads to emission reductions from the various farm operations and from machinery manufacturing (Lal, 2016).
- The timely availability of agricultural equipment, such as drills, harvesters and threshers, permits producers to plant, harvest and process crops in an efficient manner. This increases yields and reduces post-harvest losses. Case study B1.1 presents the case of smallholder conservation agriculture mechanization scheme in Zambia to increase smallholder farmers’ access to sustainable mechanization technologies for illustrative purposes.
- Precision farming equipment along with controlled release and deep placement technologies, make it possible to accurately match production inputs with plant needs. This improves efficiency in the use of inputs and reduces direct and indirect greenhouse gas emissions. In the future, larger orchards and plantations will be increasingly monitored by drones. Cameras with colour filters are able to reveal spots that require specific interventions.
- Agricultural machinery powered with renewable energy, such as wind and solar chargeable accumulators can lower producers' dependence on expensive fossil fuels. These renewable energy sources emit less greenhouse gases and reduce the need to engage in the complex logistics and construction of the heavy infrastructure required to supply fossil fuels to rural areas. However, examples of farm machinery powered by renewable energy are rare. They are often at piloting stage, but they have great potential to play a significant role in climate-smart mechanized systems.
Investments in mechanization enable farmers to expand the range of their activities and diversify their livelihoods in ways that can reduce their vulnerability to climate change. Sustainable mechanization can create opportunities to provide hired services for field operations, improve transportation and agro-processing and increase the possibilities for adding value to farm production. In a long-term approach, the initial investment in mechanization is compensated in the following years by higher returns on farming and labour; surplus production or increases in the amount of land under production; and greater efficiency in the use of resources and the associated savings.
Technologies for decision-making
Developing simple and robust scientific tools that can guide the decision-making of farmers on a seasonal and long-term basis is essential for planning strategies to address climate change.
In terms of risk management, some of the most relevant technologies relate to weather forecasting and early warning systems. The improved timing and reliability of seasonal forecasts and hydrological monitoring enables farmers to make better use of climate information, take pre-emptive actions and minimize the impact of extreme events (Faurès et al., 2010; Gommes et al., 2010). Risk reduction strategies and technologies are addresses extensively in module C5.
In modern commercial horticulture production systems, weather stations often monitor irrigation in accordance with the water requirements of crops. In this way, the irrigation is automatically adjusted to changes in climate.
Information and communications technologies can also support the exchange of information that is needed to respond adequately to climate change (see module C1).
Table B1.1. Climate-smart practices and technologies to increase the resilience of specific crop systems against disturbances brought about by climate change and their relation to climate change adaptation (CCA) and/or for climate change mitigation (CCM).
CROP SYSTEMS | CLIMATE-SMART PRACTICES AND TECHNOLOGIES FOR RISK REDUCTION | CCA | CCM | ||
---|---|---|---|---|---|
CLIMATE CHANGE IMPACTS | Climatic variability | All systems | Using quality seeds and planting materials, including rootstock and scion combinations, of well-adapted varieties is good agricultural practice and is climate-smart. Choosing crop species and varieties adapted to the prevalent or expected impacts of climate change for the given region and farming system is the most economical and environmentally friendly means of safeguarding crops against abiotic and/or biotic stresses, such as climate-driven extreme weather events and upsurges in pests and diseases. Useful traits include time to ripening, early and late maturity, blooming, and resistance to pests and diseases. Newly introduced crops and/or their varieties must be relevant to farmers, and farmers must know how best to grow them. To identify horticultural cultivars and cropping practices adapted to local requirements and environmental conditions, FAO has developed and maintains the HORTIVAR database. | ||
Systems including
annual crops
perennial crops
| Promoting intra- and inter-specific diversity over space (e.g. intercropping, using crop variety mixtures) and/or time (e.g. crop rotations) increases the stability of crop yields.
Crop associations and rotations designed for specific adaptation goals use cover crops to partially or entirely replace mineral fertilizer inputs, and/or mechanical soil tillage. In climate-smart systems, the main function of cover crops is not necessarily seed production. Cover crops need to be terminated when appropriate to achieve the agronomic goal they are designed for. When including cover crops in the crop rotation, farmers must 'adjust' the cover crops to fit into the already-existing cropping system, rather than accommodating the farming system to the cover crops. Growing a single crop, using a mixture of appropriately chosen genotypes of a given species, such as a mixture of high-yielding hybrid varieties and traditional varieties, increases the producer's resilience in the face of climate unpredictability.
Growing annual crops (e.g. leguminous crops) in the rows between perennial crops requires the accurate selection of species to avoid competition for water in the most vulnerable phenological stages. | *
| (*)
| ||
Unpredictable onset of rainfall | Systems including
annual crops
perennial crops
| The proper interpretation of reliable seasonal forecasts allows farmers to:
Select crop varieties and to adapt crop calendars to new temperatures and rainfall patterns.
Plan the timing of husbandry operations, such as irrigation; pruning to avoid damage from heat or moisture; fruit thinning to balance excessively high rates of fruit set and reduce competition for developing fruit in case of excessive flowering; protecting early bloom from late frosts through short-term interventions. | *
| ||
All systems | Implementing soil and water conservation techniques or in situ water conservation (e.g. soil mulching, rainwater harvesting) enhances crop productivity. | * | * | ||
Systems including
annual crops | Sustainable agricultural mechanization allows for timely seeding and harvesting, greater efficiency in the use of production inputs and less waste of resources, which increases productivity. To ensure timely seeding, reduce greenhouse emissions and deliver gains in energy efficiency, the use of no-tillage must be supported by crop rotations that are intensive (in space) and diversified (in time). | *
| *
| ||
Thermal alterations | Systems including perennial crops | Inducing flower by spraying or by irrigation is a short-term intervention to break dormancy when natural climate phenomena for breaking dormancy are absent.
| *
| ||
Systems including perennial crops | Shading and/or painting trunks decrease the effect of excessive sun and heat. Misting helps control both freezing temperatures and heat.
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Extreme events | Measures aiming at preventing crop losses may include: | * | |||
All systems | Selecting species capable of resisting specific extreme weather conditions (e.g. root and tuber crops in cyclone-prone areas) or species with short growing cycles from seed to yield. | ||||
Systems including perennial and horticultural crops
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All systems | Preparedness to quickly restore the production capacity in the disaster-affected areas requires knowledge of the appropriate adapted species and cultivars and rapid access to seeds, planting materials and other inputs on short notice. | * |
CROP SYSTEMS | CLIMATE-SMART PRACTICES AND TECHNOLOGIES FOR SOIL AND WATER CONSERVATION | CCA | CCM | ||
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CLIMATE CHANGE IMPACTS | Soil degradation | All systems | Increasing efficiency in fertilizer use through site-specific nutrient management practices that optimize the use of existing soil nutrients while filling deficits with mineral fertilizers. | * | * |
All systems | Using conservation agriculture improves soil health, allows the soil to grow both at the surface and at depths, and improves water retention. | * | * | ||
All systems | Minimizing mechanical soil disturbance continuously over time prevents and soil compaction, slows the mineralization of soil organic carbon, increases the effectiveness of rainfall, curbs soil erosion and reduces the risks of waterlogging. | * | * | ||
Systems including annual crops | The year-round seeding of fields in crops/mulch, if water availability permits, protects the soil from erosion and compaction, and keeps important nutrients, especially nitrogen and phosphorus, on farmers’ fields. Most nutrient losses occur during the period between seeding and the development of a dense canopy; and after harvest when there is no crop on the field. A diversified and intensive crop rotation is one that: eliminates fallow periods where possible; returns crop residues to the soil with an average carbon-to-nitrogen ratio in the 25-30 range; improves the soil and responds to specific needs related to agronomic practices (e.g. improved soil compaction) and water management either through improved drainage or reduced evaporation.
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Systems including annual crops | Making the right decisions about the production and management of organic matter from crop and livestock residues contributes to soil organic carbon sequestration, improves the structure of the soil and increase soil water storage. To help producers prioritize the use of crop and livestock residues in the face of competing demands, including soil management, animal feed and bioenergy, FAO has developed three tools. The first is the Bioenergy And Food Security Rapid Appraisal (BEFS RA), which can be used to define the amount of residues available at territorial level (FAO, 2015). The second tool is the residue component of FarmDESIGN, which assesses the implications of using residues for bioenergy on the whole farming systems (Wageningen University, 2016). The third is the residue component of the Bioenergy And Food Security Operator Level Tool, which uses a scorecard to help users select the best practices for their circumstances (FAO, 2016). | ||||
Systems/farm space management, including perennial crops | Integrating nitrogen-fixing perennial woody species (e.g. Cajanus cajan or pigeohttp://www-test.fao.org/?id=68045#503026n pea) and trees with annual crops increases soil fertility, produces biomass and reduces soil erosion. This practice also sequesters carbon and redistributes the carbon to deeper soil layers. |
CROP SYSTEMS | CLIMATE-SMART PRACTICES AND TECHNOLOGIES FOR EFFICIENT WATER MANAGEMENT | CCA | CCM | ||
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CLIMATE CHANGE IMPACTS | Water stress | All systems | Crop water productivity is improved by implementing good agronomic management decisions and practices such as selecting crop varieties that are drought tolerant and/or have a higher water productivity (i.e. that deliver more yield per liter of water); adjusting cropping calendars; encouraging deeper rooting of crops; using conservation agriculture for higher water retention; and mulching. | *
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All systems | Implementing soil and water conservation techniques (e.g. soil mulching, shading, rainwater harvesting, using fences or windbreaks to reduce evaporation) enhances crop productivity. | * | |||
Systems including perennial crops | Integrating feed for livestock from annual crops with perennial feed, particularly from deep-rooting legumes, promotes soil health and provides additional quality forage during dry periods. It also improves the quality of the diet of ruminants, reducing methane emissions from enteric fermentation. | *
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Irrigated systems
| Irrigation has become commonplace for commercial crops, such as horticulture production, because an adequate supply of water at all stages of the crop's development is the only way to produce consistent yields. In irrigated systems, increasing the efficiency of irrigation (e.g. through deficit irrigation, precise water applications, high-efficiency pumps), reducing water losses and improving water allocation and the management of water demand, optimizes yields per volume of water applied, reduces greenhouse gas emissions and brings about gains in energy efficiency, mainly in the use of fuel. | *
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Systems including | For increases in the quantity, frequency and intensity of rainfall, the following practices reduce or avoid damage to roots from waterlogging: | * | |||
annual and perennial crops | Improving drainage.
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perennial crops | Planting trees on berms. |