Scaling Out Legume-based Integrated Soil Fertility Management (ISFM) Approaches to Improve Crop Resilience to Drought

Malawi is a country that is highly dependent on agriculture for its economic growth and food requirements. The majority of crop producers are smallholders who harvest much lower yields compared to yield potentials. In maize, potential yields are 6-10 t/ha compared to national average yield estimate of 1.85 reported. The situation exists even in the presence of many efforts to support productivity, such as the Farm Input Subsidy Programme (FISP), which has enabled farmers to access chemical fertilizers, maize and legume seeds at very low prices. Poor and low soil fertility are often cited as the main causes for low yield. One of the reasons is that farmers fail to take a comprehensive approach to crop management, such as the adoption of Integrated Soil Fertility Management. A combination of improved variety, appropriate soil fertility amendments, proper timing of planting, fertilizer, application and weeding, improve crop yields in part due mitigation against drought. In contrast, a lack of the same results in drought susceptibility.

This project will introduce or strengthen the use of legumes in an ISFM approach in the cropping system for improved crop reliance to random drought and livelihoods in the drought prone district of Balaka, southern Malawi.

Given the drought-prone background of the district, the project’s main goal is to contribute to increased crop productivity and improved food security for smallholder farmers managing maize based farming systems in Malawi. The purpose is to enhance knowledge and capacity of smallholder farmers and extension officers in the use of guidelines that can be used to develop context-specific ISFM packages that are resilient to the varying climate under different clusters of soil types and resources.

The innovative approach of the project is the pluralistic nature of its entry point, which cover appropriate improved legume (s) for improved yields, food and nutrition security, improved income, soil fertility and drought mitigation.

In first season the project will introduce or strengthen legumes for household and income generation, while creating awareness on cereal legume rotation requirements. The same seed multiplication plots will used to demonstrate the management of legumes, and the rotation benefits of legumes on cereals in the subsequent season, hence effectively harnessing the plots for immediate learning and scaling out impact. In first season 100 farmers multiply seed of cowpeas and groundnuts each and another 200 for pigeon peas. Through a pass-on program, these numbers should grow to three or four fold in second and third year, while offering the farmers and researchers an opportunity to experiment and observation ISFM related benefits. The research question here is to test if using the multiple benefit entry point will stimulate better adaptation wider adoption of legume based ISFM approaches.

The main direct environmental impact will be on soil quality in terms of sequestering soil organic carbon, biological nitrogen fixation (BNF), aggregate stability, soil biological activity, soil porosity and continuity. The improvement in soil physical parameters is hypothesised to increase water infiltration and reduce soil runoff hence less soil erosion. These will in turn increase amount of soil available water for crops, offering more resilience of plants to water stress during dry spells hence more and stable yields.

Pigeonpea has been shown to increase soil fertility and can potentially improve the productivity of CA-based systems by preventing the formation of hard pan because of their deep rooting system. Intercropping maize and pigeonpea have been shown to provide more than double amount of biomass than conventional tillage and hence upon decomposition will provide the necessary fuel to microorganisms for further decomposition of the much stable maize stover. However, crop nutrient balances will need to be monitored to avoid contamination of streams and ground water. Also use of herbicides may have detrimental impacts on soil fauna and human health if types of herbicides and handling are not monitored.