Benchmarking agronomic use efficiency of N fertilizer in sub-Sahara Africa— Inventory and analyses of data from maize fertilizer trials

Submitted by charlotte.schilt on Tue, 10/02/2018 - 14:10

The Msc Internship was conducted as a part of the project “Benchmarking nutrient and water resource use efficiencies of crops”, which is developed within the program of “Mapping for sustainable intensification” set up by Wageningen UR (2013a, b; The objectives of this study are to (i) develop a database with maize fertilizer trials in Africa and (ii) understand the variability of crop responses to fertilizer application under a range of climate and management conditions and (iii) identify the driving factors that can explain those variations. A total of 50 articles were reviewed and a database was developed for maize fertilizer experiments in Africa. The database includes information of maize yield and various biotic and abiotic production factors and management practices. The experimental sites were situated in 10 countries in East, West and South Africa. Maize grain yields without fertilizer and the agro-ecological conditions varied strongly among the different regions. The responses of yields to fertilizer application also showed strong differences in Nitrogen Use Efficiency (AE) varying between -4.7 to 57.8 kg yield increase per kg fertilizer N applied. The possible range of AE values was calculated on the basis of the theoretical crops responses to nitrogen application and was set to be maximally 60 kg/kg. The observed large variation in AE was likely due to the large variation in soil and climate conditions and management practices in the collected maize fertilizer trials for Sub-Saharan Africa (SSA). The database will serve as a basis for testing the parameters used in the modelling work of the project. The database derived in this study can also be used to validate the QUEFTS model in predicting yields in regions beyond Kenya, for which the model parameters were mainly derived. A main conclusion from the current study is that in studies on the effects of fertilizer application on crop production, the nutrient uptake by the crop and/or the nutrient concentrations in the different crop organs should be measured. Only by performing these measurements, the underlying mechanisms of fertilizer use efficiency can be understood well.

Na Wang


Joost Wolf, Huib Hengsdijk