Human World

Sieg Snapp on a 10-year farming experiment in Malawi

In the African country of Malawi, scientists recently completed 10 years of study and experiment with farming practices – with the goal of developing new, more resilient methods of food production. The government of Malawi had commissioned the work. The results were released in late 2010 in the Proceedings of the National Academy of Sciences. Among the results, it appears that replacing fields of single crops like corn with a diverse blend of shrubby crops like soybeans or peanuts – along with popular cereal crops – might help increase yields and improve the health of the soil in Malawi. It might also make the local food production system less vulnerable to changes – or variation – in rainfall and climate, according to Sieg Snapp, a soil ecologist at Michigan State University, who led the study. She told us:

It’s already a variable climate. All the models are predicting that it’s going to get more variable. We were quite aware that these new systems had to be robust.

Dr. Snapp said that Malawi suffers from high rates of poverty. She said currently, the government heavily subsidizes fertilizer for small farmers to grow corn. But growing just one crop has put people at risk for hunger, she said.

A system that just relies on one crop requires a lot of fertilizer, and means that you’re vulnerable in many ways. You’re vulnerable to getting enough rain, you’re vulnerable to fertilizer price swings, which have been quite tremendous in recent years. Diversifying means you can be less dependent.

Snapp said the new practice of growing a greater diversity of crops in Malawi has already improved childhood nutrition in some parts of the country.

Dr. Snapp said farmers liked the shrubby crops – legumes that grew about three to four feet tall – because they could harvest food from them even during the dry season, when many other types of crops cannot grow. Farmers could also grow soybeans, in the same field. She said:

We found that maize can be diversified especially with these shrubby legumes, and combined with peanuts and soybeans for a really diverse diet for better health of children and also better health of the soil.

She explained that the shrubs provide a cover for the fields during the dry season, preventing topsoil from eroding away from wind or water. They also provide a benefit to the soil when they drop their leaves, and take nitrogen from the air to naturally fertilize the soil. Shw said that it replaces some of the fertilizer and “turbo-charges” the fertilizer you do use.

Snapp said that when farmers planted shrubby crops, with a layer of peanuts and soybeans beneath the tall corn stalks, they got more consistent yields from their fields, and their families had a more nutritious diet. In addition, the shrubs gave valuable nutrients back to the soil, prevented erosion, and decreased the need for fertilizer use.

January 29, 2011
Human World

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