Uganda Work Positioned to Make Fertilizer Use More Profitable for Poor Farmers - UNL CropWatch 203

Uganda Work Positioned to Make Fertilizer Use More Profitable for Poor Farmers - UNL CropWatch 203

January 17, 2013

Small-scale farmers around the world often don't have the financial means to use enough fertilizer to maximize their net returns per acre.

Crop fertility researchers in Uganda

Kaizzi, center, led a team of Ugandan soil scientists to conduct research to determine 15 crop-nutrient response functions which were then integrated by UNL collaborators into the Uganda Fertilizer Optimization Tool. Angela Nasamba, left, was a team member and is a graduate student supported by UNL through INTSORMIL.

These farmers with an average of only about five acres must first cover expenses just to survive.

Enter a Ugandan soil research team from the National Agricultural Research Organization and Makerere University led by soil scientist Kayuki Kaizzi with technical support from University of Nebraska-Lincoln soil scientist Charles Wortmann.

They have developed a way for these farmers to greatly improve profitability of fertilizer use.

"They may not be putting on enough fertilizer to achieve full yield potential, but the idea is for them to be able to achieve the best returns on their small investment," Wortmann said.

The team conducted field research to determine nutrient response for 15 crop nutrient combinations. These crops included corn, sorghum, upland rice, drybean, soybean and peanut.

Some crop-nutrient combinations were more profitable than others. For example, application of at least a low rate of nitrogen to upland rice or to drybean was much more profitable than other fertilizer uses. It was also apparent that rate of application was important to profitability, Wortmann said.

"Yield increases are less with lower rates of fertilizer but net returns on the small investment that they can afford are substantially increased," Wortmann said. "This gives them more profit, improving their financial situation so they can increase fertilizer use every year until they reach a point some year where they can apply rates that return maximum net return per acre."

Fertilizer use recommendations for Nebraska are made for each crop-nutrient combination to maximize net returns per acre. The findings in Uganda indicated a need for a more complex recommendation system that could maximize net returns on the small investments in fertilizer use for severely finance- constrained situations, Wortmann said.

"There was a need to determine the crop-nutrient-rate combinations that maximize net returns," he said. "This implied a need to consider all 15 crop nutrient response curves and their shapes simultaneously."

To enable this complex decision process, Jim Jansen, former UNL graduate student from Fordyce, Neb., worked with Wortmann to develop an Excel-Solver decision tool. Jansen has since graduated with Master of Science degrees in agricultural economics and agronomy from UNL.

The tool, called the Uganda Fertilizer Use Optimizer, considers the 15 crop nutrient response functions and determines the crop-nutrient-rate combinations that are expected to maximize net returns on investment. It runs in Excel and is similar to the UNL Water Optimizer tool (

The tool considers the land area to be planted to each crop, expected grain prices, the costs of fertilizer use and the financial capacity of the farmer for fertilizer use.

The output includes the fertilizer rate for each crop and the expected effects on crop yields and net returns.

"The net returns on investment were often greater than twice as much as when fertilizer was applied to maximize net returns per acre," Wortmann said. "The greater profitability with the decision tool is expected to gradually enable finance constrained farmers to break out of poverty and increase fertilizer use to the point of maximizing net returns per acre."

This alternative approach to fertilizer use was introduced to government and non-government Extension staff in Uganda in August 2012.

Two training events were conducted with 60 participants. Participants learned of the approach and underlying principles, use of the tool and how to work with farmers in making recommendations. Additional training is planned.

The team hopes to get funding so they can expand this work to 12 other countries in the future.

This work is funded by the Alliance for Green Revolution in Africa and INTSORMIL with technical support from UNL.


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