20 Apr Affordable and efficient maize fertilizers for Nigeria
Maize is the third most important food crop in Nigeria in terms of production after cassava and yam, with 31% used for feed and 12% for processing. The demand for maize increases annually due to urbanization and population growth (FAO, 2013).
Although Nigeria produces over 7 million metric tons of maize per year, grain yield is low, leading to a deficit in total production. Poor soil fertility is a major constraint in the predominantly maize production areas of the Nigerian savannas. Fertilizer application is widespread and is required to increase maize production. The most commonly used fertilizer is NPK 15-15-15, the suitability of which is much debated for maize. Poor response to fertilizer application is an important constraint in expanding commercial maize production.
The OCP-Africa fertilizer company in Morocco funded a project in 2017-2018 to develop affordable and efficient fertilizers to sustainably increase maize yields in Nigeria. The project is the largest in IITA that is funded by a commercial private organization. IITA collaborates with the Africa Soil Information Service (AfSIS) and with national partners Bayero University Kano (BUK), Institute of Agricultural Research (IAR), Zaria and National Agricultural Extension Research and Liaison Services (NAERLS); and with the Agricultural Development Programs (ADPs) of the relevant Local Government Areas (LGAs) for implementation. The project covers the whole maize belt of Nigeria, which measures around 225,000 square kilometers (Fig. 1). Developing new fertilizer formulations relevant for the area required characterization of the soils of the maize belt in terms of limiting nutrients, development and production of new fertilizers, and validation of new formulations in many trials across the area.
Soil characterization was done by collecting top- and subsoil samples from 3000 randomly selected locations following a hierarchical sampling design with 60 ‘sentinel’ sites, representing an area of 10 by 10 km, within cultivated land. Ten clusters, each covering an area of 1 km2, were randomly selected, with 5 sampling plots for each cluster. For each plot a composite soil sample was taken covering a 100-m2 plot. The soil samples were analyzed to determine soil organic carbon, total N, Mehlich-3 P, K, S, Ca, Mg, Mn, Zn, B, pH, ECEC, and texture. The soil limiting nutrients were identified and based on these new fertilizer formulations were produced in Morocco and shipped to Nigeria and distributed to various locations where the validation trials were established. Two new fertilizer formulations were developed and tested. Both fertilizers contained elements (in varying percentages) that are generally limiting.
About 1,322 suitable locations were randomly selected from the 3,000 soil sampling locations for the establishment of the trials. The project successfully established 872 trials in 2017. The treatments consisted of a nonfertilized control, an NPK15-15-15 treatment, and two treatments for the two new OCP fertilizers. The application rate was the same for each of the fertilizer plots, viz., three bags of the NPK fertilizer for basal application and two bags of urea for topdressing to give a comparable amount of N applied, ranging from 62 to 68.5 kg N/ha but varying amounts of P and K and including S, Zn, and B in case of the OCP fertilizers.
Both OCP fertilizers performed significantly better than the NPK triple 15, with an average yield increase ranging from 4% to 12% for OCP-F1 depending on the region. The average yield increase for OCP-F2 varied between 6% and 27%. However, the performance of the two OCP fertilizers contrasted for individual sites. If the OCP fertilizer that performs best for each individual site is considered, the average yield for OCP-F1 increased from to 14% to 23%, and for OCP-F2 from 14% to 44%, depending on the region and team that implemented the trials.
The highest average yield increase for OCP-F2 compared to NPK-triple-15 was obtained for the Katsina-Kaduna region with an increase of 750 kg/ha on average. The Niger-Kaduna region showed the highest average yield increase for OCP-F1, about 670 kg/ha on average. Average attainable yield levels with the application rate used in the trials are 4.55 t/ha except for the Kano-Kaduna region where this was found to be around 6 t/ha. The two formulations were therefore superior to the widely available NPK 15:15:15 widely used in Nigeria.
A Nutrient Expert (NE) Tool developed by the project Taking Agronomy to Scale in Africa (TAMASA) was used to make site-specific fertilizer recommendations of nutrients using the new formulations developed by OCP. In 2018, the OCP, based on its School Lab Program, provided over 1,260 NE recommendations to farmers across 72 communities (12 LGAs) in Kaduna State, Nigeria. The program is leveraging the activities carried out in TAMASA for developing an NE tool for the Nigerian savanna.