2 March 2009

Uganda: Country to Carry Out Digital Soil Mapping

Kampala — UGANDAN soils have run out of nutrients due to harsh-hot weather and unreliable rain patterns. It is hard to sustain food production without using chemical fertilisers, Prof.Mateete Bekunda,a soil expert at Makerere University, has said.

"Our soils, because of change in climate, have grown old and unproductive compared to those in Europe. Theirs are relatively young and we must make provisions for chemical fertiliser use, along side those advocating organic fetilisers state as a national priority," he said.

He said their studies have shown that areas around the Lake Victoria basin, Bunyoro and eastern Uganda can no longer sustain crops to meet challenges of a growing population.

Uganda has one of the fastest population growth rates in the world at 3.6% per year against dwindling agro-productivity. The climate has become hotter by 0.2 to 0.3 degrees in the last century.

Bekunda, however, notes that many farmers have been removing organic manure derived from crop left-overs from one area to another, rendering many parts unproductive.

"But such an undertaking is not sustainable. If you need 50kg of nitrogen in a hectare, for example, you may end up with only 2kg from the leftovers of that much dumped in the area," Bekunda noted.

On average, many small-scale farmers in Uganda produce about 800kg of grain especially beans and maize per hectare as a result of poor soils compared to 10 tonnes in other parts of the world with chemical fertiliser use. This has prompted soil experts in sub-Saharan Africa to highlight soil nutrients depletion as a crisis which must be given national priority.

Uganda's soils were last mapped in the 1950s. But since then, there has been a consistent drop in yields.

Currently Uganda is to benefit from a US$18m digital map of Africa's depleted soils aimed at offering insights into soils boosting food production.

The Bill & Melinda Gates Foundation and Alliance for a Green Revolution in Africa awarded the money to International Center for Tropical Agriculture in January this year.

"We are hosting a meeting in Kampala soon to make fertiliser recommendations to the government and the farming communities," Bekunda said.

The project will produce the first-ever, detailed digital soil map for all 42 countries of the region. It will combine the latest soil science and technology with remote satellite imagingand on-the-ground efforts to analyze thousands of soil samples from remote areas across the continent to help provide solutions for poor farmers, who suffer from chronically low-yielding crops largely because of degraded soils.

He said the farmers and investors in the agro-sector should test their farm soils before planting. Makerere Universty recently developed a simple soil-testing kit which among other things gives a farmer an idea of the nutrients on a farm.

How to take soil samples

- To have a soil analysis done, you need to collect 12 or more cores which will be combined as one composite sample. The samples should include soil from the surface to a depth of 6 inches in all areas except for lawns where cores should be taken from a depth of only 2 to 3 inches.

- A simple garden trowel can be used to collect the samples. Place the samples in a clean bucket and mix them thoroughly. It is imperative to use clean sampling tools.

- Pesticide or fertiliser residues will create misleading results.

- The sample must not be excessive.

This test provides unbiased, scientific information on the soil pH value (how healthy the soil is), the current soil levels of phosphorus, potassium, calcium, magnesium, zinc and manganese and fertilizer and lime recommendations for the plants you are growing.

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