Sustainable agriculture refers to the practice of production of field crops, vegetables, livestock, and fisheries using farming techniques that protect the environment, public health, human communities, and animal welfare. It integrates three main goals:
- environmental health;
- economic profitability; and
- social and economic equity.
Sustainable production systems should exhibit several key attributes at the production end of food systems .The
concept of sustainability in the scenario of food and agricultural production is the chief factor to any future challenges. It follows the following four underlying principles:
1. Persistence: it refers to the ability to carry on the desirable outputs over a long period, therefore confers predictability.
2. Resilience: it refers to the ability to absorb, use or even take benefit from the harsh condition and to exist without any qualitative and contextual modification or changes in structure.
3. Autarchy: it means the ability to provide desirable outputs from factors of production (inputs and resources) obtained from within key system boundaries.
4. Benevolence: it centers around the concept of the ability to generate desirable outputs (food, fibre, fuel, oil) with due consideration to sustain the function of ecological service and not degrading natural capital (eg, biodiversity, minerals, soil, clean water etc.).
Approaches of sustainable agriculture
Sustainable agriculture is a broad term that encompasses a variety of approaches. Planting climate-resilient and high-yielding crop varieties, intercropping legumes in cereals, biodiversification, participatory breeding, conservation agriculture, and Integrated Pest Management are all examples of sustainable intensification. There are several approaches used to ensure sustainable agriculture.
1. Crop rotation
Crop rotation is a method of growing various crops in a specific order on the same piece of land in order to preserve soil fertility and productivity over time. It aims to maximize resource efficiency and sustain soil fertility levels that are beneficial to plants, allowing for higher and higher-quality production with minimal environmental impact. Crop rotation disrupts insect and pathogen reproduction and hence their life cycle. Plant nutrients are restored when certain plant species are included in crop rotation, requiring less chemical fertilizer. Crop rotation is a useful technique in the practice of sustainable agriculture. Rotation necessitates more time for field preparation prior to rotation. Fungi and pests from a previous crop can cause problems with the new crop. Some crops are better at coexisting with weeds and fungi than others, and growing new crops can be challenging. When a new crop is planted, plant residues can also cause diseases.
Permaculture is an approach and concept coined by David Holmgren and Bill Mollison in Australia in the 1970s (Lampeter Permaculture Group 2006). It is the harmonious integration of people and landscape providing foods, feeds, fibres, shelter, energy and other material and non-material needs in a sustainable way (Mollison 1988). The practices of permaculture consist of: (i) harvesting or rainwater, (ii) composting, (iii) use of pollinators (flowers, insect houses), nitrogen-fixers (clover), birds and bats (water features, food, habitat), etc. iv) replacing lawns and grass with productive crops, growing perennial food plants, (v) practice of no tilling, no chemical and synthetic fertilizers or pesticides, mulching, cover crops, and (vi) practicing agroforestry. Permaculture’s unique problems can be related to concerns about its economic viability. This is a well-known strategy that could only be considered effective on a smaller, more self-sufficient scale. Permaculture can help farmers increase their yields and productivity.
3. Polyculture farming
Polyculture is a method for growing two or more crops at the same time and in the same place. As a result, a polyculture crop production method entails the cultivation of several crops at the same time or in a crop rotation. Polyculture is an integral part of sustainable agriculture because it allows better use of both crop space and labor resources than monoculture. It allows efficient use of natural resources and produces a consistent yield under a variety of environmental conditions. In the cropping method, intercropping with legumes is beneficial. Farmers find it difficult to monitor and supervise ongoing farm operations when more than one form of plant is grown on a farm in a polyculture system. Farmers are becoming more knowledgeable about their crops as they cultivate a variety of crops. Planning and establishing a polyculture sector can be a time-consuming process. Polyculture cultivation can necessitate a higher initial investment in specialized equipment to meet the requirements of each plant species. A larger infrastructure is needed for polyculture. Polycultures will help us diversify our agricultural systems
4. Biodynamic farming
Dr. Rudolf Steiner, a scientist and philosopher, developed biodynamic agriculture in the early twentieth century as a method of sustainable agriculture. Biodynamic plants are those that are grown in the field in living soil, where they receive the nutrients that chemical fertilizers and hydroponic farming do not offer. Biodynamic farming encourages the use of poultry, composting, crop rotation, and cover cropping to preserve their own fertility. Centered on the theory of “anthroposophy,” biodynamic farming combines holistic and ecological growing methods. Composting, using livestock manure from farmed animals, and cover cropping are all examples of sustainable agricultural practices. Biodynamic agriculture’s unique strengths) may be construed as its unique challenges, in that it has a strong spiritual component, caters to a niche market, and necessitates its own training and quality label. Biodynamic farming necessitates more labor than conventional farming practices, increasing the cost of the produce. It is also not very conducive to mechanization, so it is difficult to practice on a large scale.
5. Integrated Nutrient Management
Integrated nutrient management (INM) is the process of optimizing the benefits from all possible sources of organic (farm yard manures, poultry manures, crop residues, green manures), inorganic (biofertilizers, etc.) and biological (biofertilizers, etc.) components in an integrated manner to maintain soil fertility and plant nutrient supply at an optimal level for maintaining the desired productivity. INM practice may be a cutting-edge and environmentally friendly approach for global agriculture sustainability (Wu and Ma 2015). Integrated Nutrient Management is the process of maintaining optimal soil fertility and plant nutrient supply in order to maintain desired productivity. The aim of INM is to integrate the use of natural and man-made soil nutrients to increase crop productivity and preserve soil productivity for future generations. The advantages of IPN are:
- enhance the availability of applied as well as native soil nutrient,
- synchronizes the nutrient demand with the native supply from native and applied sources,
- provide balanced nutrition to the crops,
- improves and sustain the physical, chemical and biological functioning of soil,
- minimizes the deterioration of soil, water and ecosystem by promoting carbon sequestration
- reducing nutrient losses to ground surface water bodies and atmosphere
- minimize the antagonistic effects resulting from hidden deficiency and nutrient imbalance.
Efficient use of all nutrient sources, including organic sources, recyclable wastes, mineral fertilizers and bio-fertilizers should therefore be promoted through INM.The degradation and over-exploitation of land is a big constraint to INM. For adoption of INM, farmers should have knowledge on use of fertilizers in balanced proportion. They have to purchase manure, fertilizers that are important for INM. Because of growing population, land is fragmented and farmer’s holdings lands are becoming smaller. This prevents the application of INM at commercial level.
6. Integrated Pest Management (IPM) and Bio intensive IPM
Integrated Pest Management is a method of pest control that uses a combination of biological, cultural, mechanical, physical, and chemical tools to reduce economic, health, and environmental risks. Following pest detection, IPM recommends using biocontrol agents in the early stages and chemical agents as a last resort. IPM is an essential part of the long-term sustainability strategy. In an effort to increase the sustainability of an agricultural system, IPM “programs” are formulated on a combination of cultural, biological, mechanical, and chemical control methods It is found that IPM-FFS (integrated pest management-farmers’ field school) trained farmers used 36% lesser amount (1.82 kg/ha) of active ingredients of pesticides than the non-trained farmers (2.85 kg/ha).
compared with non-FFS areas. Application of IPM takes time. Much time is needed in planning itself. Individual farmers should have knowledge on the various control methods available.
The term “biointensive IPM” refers to a “systems approach to pest management focused on a knowledge of pest ecology.” It starts with measures to effectively identify the existence and source of pest problems, then employs a variety of preventive strategies and biological controls to keep pest populations under control (Reddy 2012). Reduced chemical input costs, reduced on-farm and off-farm environmental effects, and more efficient and sustainable pest control are some of the advantages of introducing biointensive IPM. Some considerations for design improvements in the agricultural system; choice of pest-resistant cultivars; technical knowledge needs; control choices, record keeping, and equipment should be taken into account when designing a biointensive IPM program.
7. Cover crops
Cover crops are crucial to sustainable agricultural systems. Through their rooting, these crops aid biological soil tillage; the surface mulch provides food, nutrients, and energy to earthworms, arthropods, and microorganisms that biologically till soils below ground. Under zero-tillage regimes, deep-rooted cover crops and biological agents (earthworms) can also help alleviate compaction. Cover crops can be thought of as a long-term investment in better soil quality and farm management . They help to reduce soil erosion by increasing surface residue. They boost the soil’s structure and water-holding capability, increasing the effectiveness of nitrogen fertilizer application. In crop rotations, cover crops can suppress weeds, provide shelter for beneficial predator insects, and serve as non-host crops for nematodes and other pests. Legume cover crops such as hairy vetch and crimson clover fix nitrogen and contribute to the nitrogen requirements of subsequent crops. Plants like clover or oat can check soil erosion, maintain soil fertility, suppress weed growth and improve the quality of soil.
Agroforestry is a land use management system that combines agricultural and forestry technologies to establish more complex, profitable, and long-term land use systems. It’s an old technique used by farmers all over the world. In Nepal’s hilly areas, the agroforestry method is widely used. It integrates fast growing, N-fixing woody species into small scale farming systems show great promise in enhancing by supplying and cycling of plant nutrients in soil-plant system. It also increases plant productivity and soil quality. Agroforestry is a holistic approach that has always played a critical role in Nepal’s agricultural system’s sustainability. Agricultural production will also improve as forestry improves soil fertility and reduces soil erosion. Likewise, agroforestry will increase food, feed and fuel wood. Agroforestry system is an ecologically rational and economically sound approach and is of great importance for the farmers in dry regions with soil prone to soil erosion causing desertification. soil and minimize the need for chemical fertilizer in the soil. These crops enhance biodiversity on the farm and contribute to a healthier ecosystem. Cover crops may be difficult to include with tillage. These crops increase insect pests and disease.
9. Natural pest predators
The predators, parasitoids, pathogens, and competitors are examples of natural enemies of insect pests, also known as biological control agents. Predation, parasitism, herbivory, and other natural processes are used in this approach, but it usually includes active human management. Biological pest control has long been regarded as one of the most promising innovations for long-term agricultural sustainability: it reduces reliance on conventional pesticides, reduces negative environmental effects, and increases worker protection while preserving crop production’s economic viability. This approach is an economical, reliable and environmentally friendly pest management method; it uses living organisms to reduce pest populations. At the same time, the adverse effect on the environment is minimized by reducing the dependence on synthetic pesticides. Natural predators are those that live in agricultural fields (environment) and are involved in hunting of pests such as aphids, pollen beetles and slugs. This approach takes the farm as an ecosystem rather than a production factor whereby effective control over pests is found by natural predation of other creatures such as birds, animals etc. The biological control is unpredictable. Its unpredictability lies mostly in the fact that the natural enemies are dependent on the environmental conditions. Biological control method is slow process to achieve the pest control.
10. Conservation agriculture (CA)
Conservation agriculture was developed in the 1970s in Brazil and Argentina. CA is based on three key principles: minimizing soil disturbance, preserving soil cover, and crop rotation management. Conservation agriculture is a set of practices which is gaining popularity and focuses on minimum soil disturbance that aims to increase production and promote profitability by reviving soil fertility status. Conservation agriculture is a system approach which is characterized by three interlinked principles namely minimum soil disturbance, permanent soil cover and crop rotation. Conservation agriculture is an agro-ecological approach to agricultural intensification that focuses on the implementation of three interconnected concepts based on locally formulated practices: minimal soil disturbance, permanent soil cover, and crop rotations. Conservation agriculture is a more sustainable and environmentally friendly management system for cultivating crops. It contributes to environmental conservation and to sustainable agricultural production by maintaining a permanent or semi-permanent organic soil cover. Conservation agriculture is a farming system designed to enhance the sustainability of agricultural production by conserving and protecting soil and water. Conservation agriculture, as a model for long-term production intensification, has a range of advantages for farmers, society, and the climate. CA strategies can have a significant positive impact on the environment, finances, social issues, and health. The key practices under CA are minimizing soil disturbance, which entails reduced or no-tillage (through direct seed and/or fertilizer placement), maintaining soil cover by growing cover crops, leaving crop residues on land post-harvest and mulching, managing crop rotation, incorporating a wider range of plant species. Specific challenges relating to the implementation of CA are its dependence on herbicides, primarily to avoid soil disturbance when preparing to sow, and the consequent reliance on herbicide-resistant crops and specific machinery adapted for direct seeding. These techniques reduce the higher levels of labour. The weight of the machinery used to plough the soil under in CA has been argued as one of the main contributors to soil compaction in the first place. Conservation agriculture could, in fact, lead to adverse impacts on the environment through its over-reliance on herbicides and genetically modified herbicide
resistant crops. From an economic standpoint, in some cases the implementation of the approach may result in the demand for labour to increase, however the costs for certain machinery, fuel and fertilizer will at the same time decrease. Conservation agriculture has come up as a new paradigm to achieve the goal of sustainable agricultural production. It is a major step towards the transition to sustainable agriculture. Conservation Agriculture requires a major change in mindset of farmers. In general, farmers should be more careful about the timing of agricultural operations. Particular attention should be paid to weed control through manual weeding or the rational use of herbicides. The CA requires a high initial cost of special planting machines.
11) Organic farming
The origins of organic agriculture can be traced all the way back to 1840, when mineral plant nutrition theory was established. The modern organic movement, on the other hand, arose concurrently with industrialized agriculture, with pioneers seeking alternative solutions to soil degradation, poor food quality, and low yields. Organic farming is an efficient and promising agricultural approach to sustainability as it ensures yield stability, improves soil health, does not cause environmental problems, and reduces the use of pesticides and synthetic fertilizers. Organic agriculture provides benefits in terms of environmental protection, conservation of nonrenewable resources, improved food quality, improve health status and the reorientation of agriculture towards areas of market demand. Organic farming avoids the use of unhealthy traditional agricultural methods including synthetic fertilizers and pesticides. It preserves, protects, and enhances the ecosystem’s quality. As a result, it is eventually linked to long-term growth. According to the European Commission, the principles of organic farming are:
- The responsible use of energy and natural resources,
- The maintenance of biodiversity,
- Preservation of regional ecological balances,
- Enhancement of soil fertility, and
- Maintenance of water quality. Organic farming also encourages a high standard of animal welfare and requires farmers to meet the specific behavioral needs of animals. Specific challenges relating to organic farming are often linked to evaluating its feasibility, often because many changes may only be observable in the long term. The benefits of sustainable agriculture underlie minimization of cost of inputs, maintain and conserve biodiversity; checks air pollution and soil erosion and speak for better treatment of animals. The drawbacks of sustainable agriculture are limited use of land without optimum use, reduced income, time consuming, more effort requirement and short shorter shelf life of products. The main disadvantage of sustainable agriculture is the limited land use, which makes it difficult to produce large quantities of food. As the land is used sparingly, the income from agriculture is very limited. Since the use of chemicals and fertilizers is minimal, it is very difficult to increase the fertility of the soil without using fertilizers and other chemicals. Successfully cultivating plants with minimal or no use of machinery takes longer and more people, which slows production.