Development and utilization of a decision support tool for the optimization of fertilizer application in smallholder farms in Uganda

Abstract

This paper presents the development and pilot of the Fertilizer Optimization Tool (FOT), a decision support tool for use by extension agents in  advising smallholder farmers in Uganda in applying optimum (rather than maximum) fertilizer by considering the farmers’ financial abilities. The FOT is made up of three components which includes, the optimizer tool, the nutrient substitution table, and a fertilizer calibration tool. The FOT was developed using field trial data collected on specific agro-ecological zones and mapped using global positioning systems in 13 Sub-Saharan Africa countries. The FOT provides site- and farmer-specific fertilizer recommendations, providing both economic and environmental benefits. Results are based on a survey of 241 households, 57 technical personnel and tracking of 33 FOT users over a 3-season period. Results show a progressive shift in farmers’ attitude towards the value of fertilizer. More FOT users (71%) disagreed with the statement that fertilizers destroy soils, compared with  non-FOT users (52%). Crop yields (tons/ha) were significantly higher for crops receiving fertilizers compared to those not. While it is generally accepted that using fertilizer improves crop response and achieves better yields, the value of FOT was reported in terms of rationalization of investment by farmers. The average seasonal investment was approx. $43, giving a return on investment of over 107%. Given the evidence  generated from Uganda, there is a need for considering out scaling the FOT technology to other countries in Africa, which are faced with the same challenges of low fertilizer use among smallholder farmers. Using the mobile FOT app provides a further cost-effective opportunity to out scale the approach to benefit more smallholder farmers in sub-Saharan Africa. Further development of the FOT is suggested, particularly in the wake of increased focus on multi-nutrient fertilizer blends, and the need to adjust for soil PH, moisture, and long-term impacts of nutrient substitution.

Key words: decision support tool, fertilizer optimization tool, precision agriculture, site-specific fertilizer recommendations