A fertilizer optimization tool undergoes validation in Kenya


A computer-based tool has been developed to help farmers calculate the amount of fertilizer for various crops.

Agricultural experts say that this tool maximizes profit to fertilizer use depending on the farmers’ financial ability.

The Head of Natural Resource Management at the Kenya Agricultural and Livestock Research Organization (KALRO), Dr. Anthony Esilaba, says the tool is very useful to farmers and it will go a long way in improving the efficiency in the utilization of fertilizers as a resource in the country for the scientist, the extension worker and the farmers.

The University of Nebraska-Lincoln, USA, has developed the Fertilizer Optimization Tool (FOT) for 13 countries in Africa with support from Alliance for Green Revolution in Africa (AGRA). It’s meant for eight agro-ecological zones in Kenya.

Charles Wortmann a Professor of Agronomy and a Soil Fertility Specialist at the University of Nebraska-Lincoln says, “FOT can be used by small-holder farmers without enough money for fertilizer.”

“It’s also appropriate for large-scale commercial farmers who have the finance to fully utilize fertilizer.” He  added.

Prof. Wortmann explains that for farmers to adopt more fertilizer use, they need to see the profit potential. Once farmers have the perception of good profit without too much risk, they respond.

The Excel-operated tool is dependent on economics and programming. It considers different nutrients supplied to different crops to determine the combinations that will give the farmer the most profit.

Rates of application

Dr. Esilaba acknowledges that they’ve had problems in determining the rates of application and the types of fertilizers that should be applied and when they should be applied.

He’s hopeful that the tool will come in handy in appropriately allocating resources especially at the farm level, so that farmers reap maximum productivity.

Dr. Esilaba, a soil scientist, says about 2,000 people are targeted for training in the next two years, mainly in western, central, eastern Kenya and the coast, to use this tool among other technologies being disseminated; “We shall also proceed to deal with climate-smart agriculture.”

He points out that Kenya doesn’t use enough fertilizer. So far, in Africa the rate of fertilizer application is only 10kg per hectare,” whereas internationally, countries like India and others in Asia use over 100kg, while Europe and America, over 200,000kg.

Kenya’s fertilizer application is over 30kg per hectare according to KALRO. This is attributable to schemes especially with cash crops; tea, coffee and others, where a lot of fertilizers have been supplied to farmers through various Cooperatives and Societies. There’ve been programs too, that provide accelerated use of fertilizers through the Ministry of Agriculture.

“We still have to improve,” since, “The target for most African countries was 50kg per hectare,” states Dr. Esilaba.

Senior Research Officer at KALRO, Dr. Catherine Kibunja, who also coordinates integrated soil fertility management, says, The FOT is an easier way of recommending fertilizers for farmers.

One of the most comprehensive fertilizer recommendations in Kenya was done almost 30 years ago. It was funded by GTZ. Practically all regions in Kenya were covered in an exercise that took about 10 years. “We need to upgrade what we have. This tool will do it efficiently in a shorter time than the previous one,” Dr. Esilaba anticipates.

The tool also caters for a farmer with livestock and therefore has constant manure. Such a farmer may decide to use what’s available on his farm and avoid spending on fertilizer.

The first version of the FOT was developed in 2012 for Uganda. Six different crops were tested for Nitrogen, Phosphorus and Potassium (NPK) nutrients.

Some economists conversant with maximizing profits were engaged and the tool was realized. Since then, it’s been expanded. Uganda is considered a success story.

Dr. Esilaba contrasts, “Fertilizer usage in Uganda has been very minimal. Initially, it didn’t even recommend fertilizer use.” But, “In Kenya, it has been higher.” He believes, if properly executed, the impact of FOT can be higher in Kenya than in Uganda.

“In Uganda, farmers have been able to increase their profit from their capital investments by more than 300% when they applied this tool on sorghum and soya beans. The biggest increase they got was on rice,” Dr. Kibuja says.

This tool is now undergoing validation in Kenya. It has been tried in Mbeere, discloses Dr. Kibunja, and it is working.

The FOT gives the farmer a choice. He decides which crop he wants and how much money he wants to commit on a portion of his land. If a farmer has, say, five acres and plants multiple crops, the FOT assists him to settle on a decision that will maximize the returns on that piece of land.

FOT is fully based on field research data; some of it conducted in the past such as under Fertilizer Use Research Project (FURP) in the 80s but still considered useful. Results from current field research are also incorporated.

Prof. Wortmann assures, “We’re not making some guesses here and there, but looking at the results and doing the best in interpretation and then making application to different agro-ecological zones.”

According to Prof. Wortmann, the FOT does not require soil testing. But to fine-tune it, soil testing is recommended. If a farmer finds that his soil is high in phosphorus, he is advised to ignore the fertilizer recommendation by the tool and use the money for something else. If potassium is low, he’s advised to adjust the recommendations according to the guidelines provided.

A Senior Laboratory Technologist at KALRO, Erastus Mutunga, is quick to point out why soil testing is necessary, “If the acidity level is less than five, the roots will be damaged. Such soils would need lime.”

Dr. Esilaba is of the view that the FOT should be downgraded to a level that an ordinary farmer can easily glean through. It could be on paper and in tabular or graphical form. Dr. Jama concurs.

Prof. Wortman concedes that the big challenge he foresees is to avail it to farmers, extension workers and retailers. Changes in climate do not seem to bother the developers because; they work with averages across years.

Dr. Kibunja reveals that demonstrations have been done in many counties—Trans Nzoia, Eldoret, Migori, Busia, Embu, Murang’a, Machakos, Narok, among others. “We’re seeing an increase of about 200% already.”

She says the next phase of this project will be to train extension workers, fertilizer agents, distributors and the Ministry of Agriculture staff in at least 27 counties.