Alden Braul, an agronomist with the Foodgrains Bank answers some questions about conservation agriculture.
What is Conservation Agriculture?
Conservation agriculture is a revolutionary new farming system that improves food production and food security for smallholder farmers, especially those living in semi-arid regions of the world. It is based on three principles:
- Minimal soil disturbance through reduced or no tillage;
- Permanent organic soil cover using mulches; and
- Diversified crop rotations and associations (inter-cropping) with legumes.
These three principles are applied in a variety of farming contexts which vary in mechanization level and dependence on external inputs. Conservation agriculture is successful in highly mechanized farming systems using large quantities of fertilizer and herbicides. Conservation agriculture is also successful in smallholder farming situations where mechanization is limited (i.e.: hoe or animal traction) and access to external inputs is limited or not accessible.
The target group of projects supported by the Foodgrains Bank is mainly resource poor/food insecure smallholder farmers. In this context, conservation agriculture is often promoted using a hoe-based low external input approach. Farmers open permanent planting stations (15 cm x 15 cm) with a hoe in the dry season. Soil cover is maintained by supplementing existing mulch with off-field sources of organic residue. Manure and/or fertilizer is added to the planting station and covered with soil.
When the rains begin, farmers can immediately plant their field without having to wait to till their fields with a hoe or a plow pulled by oxen. Weed control is largely achieved with the mulches if they are thick enough or some surface hoeing. Herbicides are seldom used.
What are the Advantages?
There are many advantages of conservation agriculture compared to the traditional practice of removing crop residue and tilling the soil.
- Increased Water Capture: Clearly, one of the greatest advantages of conservation agriculture, especially in arid areas, is that of water capture. Soil water evaporation is decreased with the protective cover of mulches and reduced tillage. As soils under conservation agriculture have higher organic matter levels, the water holding capacity of the soil is increased.
- Improved Soil Fertility: Soil erosion is reduced with the organic soil cover provided by the mulch. Decomposition of the mulch improves the soil fertility and increases the biological activity of the soils. The addition of legumes, either by association or in rotation with cereal crops, adds valuable nitrogen to the soil.
- Earlier Planting: The conservation agriculture fields can be planted earlier because no tillage is required after the first rains begin. Earlier planting generally leads to higher yields because of improve water use efficiency.
- Higher Yields: Conservation agriculture produces higher crop yields by using water and nutrients more efficiently.
- Reduced Labour: There is an ongoing debate around whether conservation agriculture reduces or increases labour. Based on the findings of a Foodgrains Bank conservation agriculture evaluation, farmers identified less labour was required when maize was produced using a conservation agriculture system as compared to the conventional production system.
- Gender Sensitivity: The increased food production and reduced labour of conservation agriculture makes this farming approach the best choice for women who are largely responsible for the household food production and food security in many smallholder farm households. In addition, conservation agriculture is often practiced using smaller intensely managed plots close to the homestead that further simplify management.
What are the Challenges?
As with any cropping system, there are challenges with conservation agriculture. Some of the main challenges include the following:
- Mulch Scarcity: Maintaining soil cover with mulches is a key principle of conservation agriculture. In many contexts, especially in arid areas, mulch is difficult to source given the feed demands of livestock during the dry season. Burning is also a common practice which results in mulch layers being destroyed. During consecutive droughts, there is little crop residue to even begin covering the soil.
- Input Incentives: Unfortunately conservation agriculture has often been promoted with an input incentive package of fertilizer, seeds and sometime herbicides. Smallholder farmers have willingly practiced conservation agriculture while they received these inputs, but abandon the practice when the development organization leaves the region to promote the concept elsewhere. Experience shows the importance of promoting conservation agriculture using a knowledge-based approach that doesn’t depend on external inputs.
- Education and Training: Many farmers are not aware of conservation agriculture or deeply suspicious of a farming system that doesn’t involve soil tillage. Overcoming these barriers, often deeply rooted in cultural values and other mindsets, is difficult to overcome.
- Land Tenure: Smallholder farmers in many parts of the world do not own their land, and therefore making a significant long-term investment into land with conservation agriculture is very risky.
- Policies: Policies promoting conservation agriculture are often linked to using external inputs like fertilizers, herbicides and machines for animal traction. For subsistence smallholder farmers, these inputs are not accessible due to financial constraints. Therefore, policies tailored to promote a friendly version of conservation agriculture for resource constrained smallholder farmers are needed.
Where are people practicing conservation agriculture?
Conservation agriculture is currently practiced on about 125 million hectares worldwide, up from 2.8 million hectares in 1973/74. This expansion has been limited to highly mechanized farms primarily located in Brazil, Argentina, United States, Australia and Canada. In Sub-Saharan Africa, adoption of conservation agriculture amongst smallholder farmers is at the beginning stages despite 15 years of promotion. Nearly 1 million hectares are managed using conservation agriculture principles in Sub-Saharan Africa, most of which using mechanized high external input management systems. There is very limited adoption of conservation agriculture by smallholder farmers.