Four approaches to sustainable agriculture management are as follows:
1. Sustainable Land Use Management:
The term sustainable land use is comprehensive. Land is used to mean soils, forms of terrain, climate, vegetation and fauna.
Land quality can differ with respect to the availability of water and nutrients for agricultural and forestry purposes, the resistance of the soils and soil-use with respect to erosion, the natural productivity of pasturelands and forests and terrain attributes affecting mechinsation.
The following principles of sustainable land management refer primarily to such uses which combine technologies, policies and activities aimed at integrating socio-economic principles with environmental concerns so as to simultaneously:
(a) Maintain or enhance production services (productivity),
(b) Reduce the level of production risk (security),
(c) Protect the potential of natural resources and prevent degradation of soil and water quality (protection),
(d) Be economically viable (viability), and be socially acceptable (acceptability).
There five objectives of productivity, security, protection, viability and acceptability are called the basic principles of sustainable land management. Accordingly, in future, sustainable food production must meet the goals of increased production and productivity, reduce impact from pollution, and reduce resource degradation combined with social and economic viability.
Productivity is one of the basic characteristic properties of land-use. A distinction is often made between the short-term consistency or stability of production and the long-term maintenance or sustainability of production.
Stability refers to the degree in which productivity is constant in the face of small disturbances caused by normal fluctuations of climate and other environmental variables. Sustainability refers to the ability of a system to maintain productivity in spite of intensive stress.
The sustainable land management plays a significant role in soil and water conservation. The land use reduces raindrop impact and run-off and soil loss and results in improvement of soil through intervention of trees on agricultural land. The trees themselves are responsible for erosion control.
This is achieved in two ways, with trees acting as barriers and as cover. The barrier functions as conventional approach to erosion control by checking run-off of water and suspended sediment. The cover function involves reducing raindrop impact and run-off by increasing soil cover with living or dead plant materials.
Agro-forestry system as a goal of sustainable land use has high potential to satisfy the objectives of:
(a) Protecting and stabilizing the ecosystems,
(b) Producing a high level of output of economic goods such as fuel, fodder, small timber etc., and
(c) Providing employment in rural areas.
Agro-forestry system is capable of operating on smallest or largest scale; it is far less demanding in energy, machinery, irrigation and far from damaging the environment. It conserves and improves both soil and atmosphere.
Agro-forestry system employs a combination of woody perennial species and agricultural crops. It includes plantation crops, with shade trees over tea or cacao plantations and alley cropping in tropical regions. There are three different roles in sustainable land use. First, increasing diversified production, especially under conditions of land shortage.
This is not only seen as a means to improve the availability of required agricultural and tree products, but also as a means to relieve pressure on valuable conservation areas. Second, contribution to sustained production of crops and livestock either on fragile lands, or in areas of lagging economic development and prevalence of low external input agriculture. Third, contribution to land rehabilitation and increased production on degraded lands.
The role of trees may have a direct productive role. The productivity of trees often compares favourably to annual crops because of their photosynthetic activity throughout a longer growing season, coupled with relatively low demands for efficient uptake of nutrients. Together these factors assume improved conditions for the maintenance of both short-term and long-term production capacity.
Agro-forestry systems display several features which cause the management of these systems to be relatively adaptable to various changes in the production conditions. For instance, the multi-species composition of agro-forestry systems spreads the risk of crop failure, while the multiple roles of trees may allow for adjustments in production according to actual needs.
These systems are relatively flexible in the timing of output of tree products in relation to needs. Furthermore, the farmer’s dependency on external inputs with fluctuating costs is reduced by the service function of trees for crop production.
3. Organic Farming:
Organic farming is a production system which favours maximum use of organic materials like crop residues, animal excreta, legumes, on and off term organic wastes, bio-pesticides. It also discourages the use of synthetically produced agro-inputs for maintaining soil productivity, fertility and pest management under conditions of sustainable natural resources and healthy environment.
The debate surrounding farming systems often tends to be characterised in terms of the contrast between intensive farming and organic farming systems. One emerging farming system, also known as integrated farming, includes elements of both conventional and organic farming systems.
Integrated farming system involves the utilization of locally available resources such as feeds, wastes and other outputs from internal subsystems and a high level of nutrient recycling to the maximum extent possible, Thus it reduces wastes and improves the overall efficiency in the use of resources. The use of synthetic chemicals for fertilizers and pest control is limited to the maximum extent possible, but not excluded altogether.
The basic principles of organic farming require to avoid all forms of pollution, including managing genetic diversity, protecting plant and animal habitat, and aquatic system. These principles are given equal status with those of production and economic viability, so that organic farming systems consider environmental protection as one of the significant outcomes of farming systems.
Important among them are as follows: First, managing soil quality in terms of chemical and bio-logical fertility. Second, improving physical properties of soil such as aggregate stability and water holding capacity and decreasing bulk density.
Third, improving ground water quality, lower nitrate leaching and less load of antibiotic in drinking water. Fourth, improving air quality in terms of CO2 emission. Since organic agriculture solely relies on renewable energy source, external energy inputs of fertilizer and pesticides are low and their role on environmental degradation is minimum.
We may conclude that among other agricultural systems, organic farming is characterised by setting up high standards on sustainability. It should ideally be defined as a self-sufficient environmental production system in equilibrium and is based on local renewable resources.
Thus, it includes environmental considerations that are not included in conventional systems. These considerations are ground water protection from pesticides and to a certain degree nitrates, optimum animal health and welfare, biodiversity in the farming fields and surrounding areas and positive effects on rural and social development.
4. Integrated Pest Management (IPM):
It is an ecologically based pest control strategy that relies heavily on natural mortality factors such as natural enemies and weather, and seeks out control tactics that disrupt these factors as little as possible. In other words, it is a strategy for the reduction of pest damage through the careful integration of a number of available pest control options.
It is the farmer’s best mix of control tactics in relation to long-term yield levels, profits and safety alternatives. The aim is to reduce the use of chemical controls, and to maximise the use of biological and cultural components, including host-plant resistance and biological control agents.
Some people view IPM as an alternative to chemical control with synthetic pesticides while others view it as the use of natural botanical extracts in place of synthesised chemicals. But there is little agreement on the exact levels of chemical pesticides that are in an IPM process.
An important feature of IPM is that it is not prescriptive, but is an approach that makes use of whichever technology or combination of technologies is appropriate and available, seeking always to minimise pesticide use where this is feasible. In situations, where pesticides have never been used, IPM programmes can still be developed, using all other appropriate control technologies available.
IPM involves managing the pest in the context of the farming system in which crop damages being caused with clear reference to the time frame and the social, economic and environmental factors that may influence the specific production problems.
The main objective of IPM is that effective crop protection does not require the ecological disruption of completely wiping out pests. The goal is to reduce crop damage to a level where it is economically tolerable, using control measures whose cost both economic and ecological, is not excessive.
A number of non-chemical cultural practices form the core of IPM. These include crop rotation, planting more than one crop, protect a crop during the most vulnerable stages of growth, manipulation of water and fertilizer, field sanitation (such as ploughing under harvest stubble to remove pest hideaways), and use of trap crops to lure pests away from the main crop.
Biological control is one of the most powerful IPM techniques. It employs natural predators, parasites, and diseases to keep pest population below harmful levels. Moreover, a crucial step in IPM is to determine economic damage thresholds. These help farmers to decide when to take action if preventive measures are insufficient.
The farmers develop a monitoring system to count pests, track their life cycle, and ascertain whether it is time for remedial intervention. When pest numbers surge beyond the economic damage threshold and remedial measures are deemed necessary, IPM tries to minimize their environmental impact. If pesticides are used, dosages and application times are carefully adjusted to avoid killing pest predators.