Soil analysis for fertilizer recommendation in Kenya: A review

Agriculture is key to Kenya’s economy and food production but the per capita food production has been declining. Soil nutrient depletion has been identified as one of the major causes of the declining food production. However, use of chemical soil tests which is one of the main tools for predicting the probability of crop yield response to fertilizer is not clearly established. The review summarizes publications between 1970 and 2017 with focus on studies involving soil analysis and fertilizer recommendation in Kenya. We found that soil analysis data is rarely used for fertilizer recommendations. Though soils are still being analyzed by individuals and research organizations, they are done as a necessity since the studies involve some aspects of soil fertility. The findings are usually used as an explanatory variable to yield and management history and rarely for interventions. This was mainly due to lack of locally validated guidelines on how to interpret the information for a given crop, soil and agro-ecological zone. The government is the main source of information for fertilizer use strategies. However, their recommendations using soil analysis are solely based on specific crop requirements derived from literature. It does not consider the soils’ capacity which results in vague recommendations given the highly heterogeneous nature of smallholder farms. There are also no uncertainties included in the recommendations. Extension services give a general one-way information with no alternatives on how to fine tune in specific scenarios. There is still a need to carry out long-term field trials following appropriate established methods whilst using previous findings as a guide.