Zambian fertilizer trees improve soil, maize yields

Small scale farmers and researchers from the University of Zambia are using “fertilizer trees” to reduce the amount of fertilizer needed to grow crops. The new innovation has been spurred by the increasing prices of synthetic fertilisers, keeping them out of reach of small scale farmers.

Fertilizer trees are nitrogen-fixers, capturing it from the air and transferring it to the soil. This restores nutrients and increases crop productivity, with the potential to double or triple harvests.

The trees are already common in Zambia and are said to be affordable to small scale farmers. They can be planted among crops for up to three years before being cut and left to decompose, providing fuel and more fertilizer.

Dr. Olusegun Yerokun is a soil scientist and senior lecturer at the University Of Zambia School of Agriculture Sciences. He says, "Where crops don’t have roots that are deep enough to access some of the nutrients these trees can go deeper, mine the soil and then food crops can use the nutrients brought up to the surface by the tree roots.”

Policymakers and agricultural scientists drew up plans for implementing the program at a conference in Malawi in February. The project is targeting 200,000 farmers,about 10 per cent of the agricultural sector.

Yerokun says two centers in Zambia are already implementing the project-at Chalimbana farming bloc and Musekera Research Center in Eastern Zambia, about 300 kilometers from the Lusaka city center. Both Chalimbana farming bloc and Musekera Research Center are run by the Zambian government and are supported by the International Center for Research in Agro-forestry (ICRAF), based in the United Kingdom. He says farmers receive free tree seedlings, an information kit and training on the system as well as associated crop husbandry.

The fertilizer trees begin to improve the soil as they decompose, a process that takes about three weeks. The trees are replanted every 3 years alongside food crops.

According to Jeffrey Sachs, director of the United Nations Millennium Project, fertilizer trees are among the most promising means for achieving the Millennium Development Goal set up by the United Nations of halving global hunger by 2015.

There are four fertilizer tree systems, all of which are based on the idea of improving soil by recovering lost nutrients. More than 300,000 farmers are currently using fertilizer trees in five
SADC countries -- Malawi, Mozambique, Tanzania, Zambia, and Zimbabwe. Yerokun says the fertilizer tree initiative is nearly doubling annual maize yields in Zambia, the first country in the drought-hit region to start implementing the initiative.

VOA