Evolution of Fertiliser Use and its Impact on Maize Productivity in Kenya: Evidence from Multiple Surveys

During the 1990s, the Kenyan agricultural sector became increasingly liberalised. For many years, both government- and non-government organisations have advised farmers on fertiliser doses, and therefore, an increase in fertiliser adoption resulting in higher yields has been expected. We analyse the evolution of fertiliser use and its impact on maize productivity and household incomes in Kenya, using four household surveys conducted between 1992 and 2013. Each survey represented all six maize-producing zones of Kenya. The results show that the percentage of fertiliser users among maize farmers has increased slightly over the years (from 62% in 1992 to 65% in 2013), and the quantity of fertiliser applied per ha has increased (from 82 kg/ha in 1992 to 100 kg/ha in 2013) but remains far below recommended levels. Therefore, maize yields have remained stagnant, or even decreased slightly (from 1360 kg/ha in 1992 to 1116 kg/ha in 2013). We also observe that the following factors affect fertiliser use and maize yields: education of the household head; area under maize cultivation; agroecological zone; uneven access to extension services; and food insecurity. We also find that fertiliser use has a positive impact on both maize yields and household income. We conclude that the liberalisation of fertiliser markets in Kenya did not have the desired effect of increasing fertiliser use and consequently maize yields, except in the high potential maize-growing areas. Possible explanations include both market factors, e.g. high prices, and non-market factors, e.g. access to information. We make two policy recommendations based on these findings - firstly, the targeted outreach of extension services should be considered, to increase fertiliser use and yields in less-productive regions, and secondly, policies should be considered that incorporate provisions for weather shocks.