What is conservation agriculture (CA)?
Conservation agriculture (CA) is a concept for resource-saving agricultural crop production that strives to achieve acceptable profits together with high and sustained production levels while concurrently conserving the environment (FAO 2007).
According to the Cornell University College of Agriculture and Life Sciences;
Conservation Agriculture (CA) is a set of soil management practices that minimize the disruption of the soil’s structure, composition and natural biodiversity.
What are the benefits?
The Food and Agriculture Organization of the United Nations (FAO) believes that there are three major benefits from CA:
- Within fields that are controlled by CA the producer will see an increase in organic matter.
- Increase in water conservation due to the layer of organic matter and ground cover to help eliminate transportation and access runoff.
- Improvement of soil structure and rooting zone.
Read also: 7 Negative effects of soil tillage
Conservation agriculture has an added advantage to ultimately reverse the negative effects of climate change. A publication from the Cornell University College of Agriculture and Life Sciences outlines advantages of Conservation agriculture as follows;
Conservation agriculture is generally a “win-win” situation for both farmers and the environment. Yet many people intimately involved with worldwide food production have been slow to recognize its many advantages and consider it to be a viable alternative to conventional agricultural practices that are having an obvious negative impact on the environment.
Much of this has to do with the fact that conservation agriculture requires a new way of thinking about agricultural production in order to understand how one could possibly attain higher yields with less labour, less water and fewer chemical inputs.
In spite of these challenges, conservation agriculture is spreading to farmers throughout the world as its benefits become more widely recognized by farmers, researchers, scientists and extensionists alike.
Specifically, conservation agriculture (CA) increases the productivity of:
Conservation agriculture improves soil structure and protects the soil against erosion and nutrient losses by maintaining a permanent soil cover and minimizing soil disturbance. Furthermore, CA practices enhance soil organic matter (SOM) levels and nutrient availability by utilizing the previous crop residues or growing green manure/ cover crops (GMCC’s) and keeping these residues as a surface mulch rather than burning. Thus, arable land under CA is more productive for much longer periods of time.
Because land under no-till is not cleared before planting and involves less weeding and pest problems following the establishment of permanent soil cover/crop rotations, farmers in Ghana reported a 22% savings in labour associated with maize production. Similar reductions in labour requirements have been reported with no-till rice-wheat systems in South Asia and various CA technologies in South America. Much of the reduced labour comes from the absence of tillage operations under CA, which use up valuable labour days during the planting season.
Conservation agriculture requires significantly less water use due to increased infiltration and enhanced water holding capacity from crop residues left on the soil surface. Mulches also protect the soil surface from extreme temperatures and greatly reduce surface evaporation, which is particularly important in tropical and sub-tropical climates. In Sub-Saharan Africa, as with other dryland regions, the benefits of conservation agriculture are most salient during drought years, when the risk of total crop failure is significantly reduced due to enhanced water use efficiency.
Soil nutrient supplies and cycling are enhanced by the biochemical decomposition of organic crop residues at the soil surface that are also vital for feeding the soil microbes. While much of the nitrogen needs of primary food crops can be achieved by planting nitrogen-fixing legume species, other plant essential nutrients often must be supplemented by additional chemical and/or organic fertilizer inputs. In general, soil fertility is built up over time under conservation agriculture, and fewer fertilizer amendments are required to achieve optimal yields over time.
Insect pests and other disease-causing organisms are held in check by an abundant and diverse community of beneficial soil organisms, including predatory wasps, spiders, nematodes, springtails, mites and beneficial bacteria and fungi, among other species. Furthermore, the burrowing activity of earthworms and other fauna create tiny channels or pores in the soil that facilitate the exchange of water and gases and loosen the soil for enhanced root penetration.
Farmers using CA technologies typically report higher yields (up to 45-48% higher) with fewer water, fertilizer and labour inputs, thereby resulting in higher overall farm profits. In Paraguay, net farm income of no-till (NT) farming on large-scale commercial farms increased from $2,3467 to $32,608 more than farms using conventional tillage over a 10 year period. The economic benefits of NT and other conservation agriculture technologies, more than any other factor, has lead to widespread adoption among both large- and small-scale farmers throughout the world.
Conservation agriculture represents an environmentally-friendly set of technologies. Because it uses resources more efficiently than conventional agriculture, these resources become available for other uses, including conserving them for future generations. The significant reduction in fossil fuel use under no-till agriculture results in fewer greenhouse gases being emitted into the atmosphere and cleaner air in general. Reduced applications of agrochemicals under CA also significantly lessens pollution levels in air, soil and water.
Conservation agriculture also has the benefit of being accessible to many small-scale farmers who need to obtain the highest possible yields with limited land area and inputs. Perhaps the biggest obstacle thus far for the technology spreading to more small-scale farmers worldwide has been limited access in certain areas to certain specialized equipment and machinery, such as no-till planters. This problem can be remedied by available service providers renting equipment or undertaking conservation agriculture operations for farmers who would not otherwise have access to the needed equipment. Formulating policies that promote adoption of CA are also needed. As more and more small-farmers gain access to CA technologies, the system becomes much more “scale neutral.”
Active role for farmers
As with any new agricultural technology, CA methods are most effective when used with skilful management and careful consideration of the many agroecological factors affecting production on any given farm or field. Rather than being a fixed technology to be adopted in blueprint-like fashion, CA should be seen as a set of sound agricultural principles and practices that can be applied either individually or together, based on resource availability and other factors. For this reason, farmers are encouraged to experiment with the methods and to evaluate the results for themselves- not just to “adopt” CA technologies. Selecting among different cover crop species, for example, needs to be determined in relation to particular agroecological conditions of the farm, including soil type, climate, topography as well as seed availability and what the primary function of the GMCC will be. Similarly, planting distances, irrigation requirements and the use of agrochemicals to control weeds and pests among other considerations, must be decided based on what the farmer needs as well as the availability of these and other resources.