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Growing more: sustainable intensification in southern Africa

March 4, 2014

By Christian Thierfelder/CIMMYT

The “double-up legume system” improves food security in Malawi by increasing yield and farmers’ incomes. Photos: Christian Thierfelder

Gently undulating plains and green maize fields dominate the landscape of central Malawi as far as the eye can see. The ridges, furrows and bare soil in between, resulting from traditional land preparation, are common. Heavy rainfalls and accelerated soil erosion turn the Chia Lagoon, connected to Lake Malawi, brown and murky. The continued loss of soil fertility and the need to adapt to climate variability led CIMMYT and its partners to introduce conservation agriculture (CA) in Malawi in 2005.

The Nkhotakota district, where conservation agriculture systems have been widely adopted, shows changes in the landscape, such as residue-covered soil surfaces along the roadsides. Farmers are embracing the new CA concepts and are successfully growing maize directly planted with a pointed stick. CIMMYT and partner organizations including Total LandCare and the Ministry of Agriculture, funded by the International Fund for Agricultural Development, support these efforts. The impacts of CA in Malawi are obvious. More than 30,000 farmers in the central part of the country have been informed about the practices and now use them on their own fields, which is a direct result of CIMMYT science and the concerted efforts of private, governmental extension and national research organizations.

Farmer Christopher Helima shows a new drought-tolerant maize variety grown using conservation agriculture.

Farmer Belemoti Sikelo, from the Mwansambo Extension Planning Area, has participated in the program for more than eight years. “I used to be a farmer that always ran out of maize grain in February or March and had to work for other farmers in the area to enable my family and me to survive,” Sikelo said. “Since I started using conservation agriculture practices, we have always had enough food during the critical months. I have expanded the land area under conservation agriculture on my farm and I have also tried conservation agriculture without expensive herbicides; I believe it is possible to apply conservation agriculture techniques without chemical weed control, but it needs good management and residue cover to reduce the weed pressure. Farmers around me come and visit my demonstration plots and ask me about my secrets for a good-looking maize crop. They admire the fields where I have planted groundnuts and maize under conservation agriculture.”

Disease pressure on traditionally monocropped maize has forced farmers to rotate maize with cowpeas, groundnuts and pigeonpea. Through diversified crop rotations, they have managed to control the parasitic weed striga   (Striga asiatica L.), fungal diseases and damage from white grubs, the larvae of the black maize beetle (Phyllophaga ssp. and Heteronychus spp.). As an added advantage, they have improved family nutrition and have surplus produce to sell in local markets.

A team of researchers from Brazil, Malawi, Mexico and Zimbabwe visited longterm on-station and on-farm CA trials and demonstrations in central Malawi during 4-8 February to monitor progress and impact, in their quest to sustainably intensify smallholder farming systems.

The use of conservation agriculture multiplies these benefits. Legumes such as groundnuts, cowpeas and soybeans can be grown on flat soil with half the row spacing, which is not possible under the conventional ridge and furrow system. The increased plant population has more than doubled grain yield, provides better ground cover and reduces soil erosion. The need to grow more food on the same land area has spurred innovation. To increase legume production, farmers have started to adopt the “double-up legume system.” Growing legumes with different growth habits side-byside – for example pigeon pea with cowpea or groundnuts – increases farmers’ yields and incomes even more, while also improving food security.

Lastly, drought-tolerant maize varieties provided by the Bill & Melinda Gates Foundation-funded Drought Tolerant Maize for Africa (DTMA) project were recently introduced and are being tested under different crop management systems. With the new stress-tolerant maize cultivars, farmers can now overcome seasonal dry spells and to grow longer season varieties. The risk of crop failure is reduced under conservation agriculture due to better moisture retention on residue-covered fields. This important benefit will be key in the coming years, as temperatures will likely increase and rainfalls become more erratic.


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