Optimisation of mineral fertilisation and planting density for improving hybrid maize productivity in Senegal’s Groundnut Basin

Maize (Zea mays L.) is a major food security stable and cash crop in West Africa, particularly in Senegal, where it is a strategic crop in agricultural production. However, low soil fertility and climate variability severely limit maize productivity in the maize-groundnut intercropping system in the Groundnut Basin in Senegal. The objective of this study was to optimise the combined effects of mineral fertilisation and planting density on the productivity of hybrid maize in the maize-groundnut intercrop systems in the Groundnut Basin in Senegal. The trial was conducted at the Nioro Agricultural Research Station using a split-plot design with three replicates. Five mineral fertilisation treatments ranging from an unfertilised control to increasing rates of NPK (15-15-15) and urea assigned to main plots, and five planting density levels (53,333–133,333 plants ha-1) assigned to subplots were evaluated. The experimental crop was a hybrid maize variety, known as Kabamanoj. Planting density had no significant influence on phenology (P = 0.442), collar diameter (P = 0.18089) or plant height (P > 0.05). However, aboveground dry matter and grain yields responded significantly (P = 0.0493 and P = 0.0069, respectively), with maximum values obtained with D3 (6.85 and 5.08 t ha-1), compared to 4.71 t ha-1 and 3.98 t ha-1 for D1; representing gains of 45 and 28%, compared to the standard density D1. Application of mineral fertilisers at the rate of F2, F3 and F4, caused the earliest maize growth (P = 0.028) and best collar diameter (P = 0.0016). However, application of mineral fertiliser at the rate of F4, resulted in the highest maize grain yield of 5.56 t ha-1; representing a 25% increase, compared to the control treatment, F1. Results also showed no significant (P>0.05) fertiliser application x planting density on grain yield. Thus, adopting an optimal density D3 (111,111 plants ha-1), combined with mineral fertilisation F4, would contribute significantly to improving maize productivity in Groundnut -growing Basin of Senegal.