Effects of farmers' practices of fertilizer application and land use types on subsequent maize yield and nutrient uptake in central Benin

Four on-farm experiments in central Benin examined whether land-use succession and fertilizer treatments for prior cotton would sustain subsequent maize crop yields and achieve balanced plant nutrition. Treatments consisted of three prior land use successions, i.e. before planting maize (egusi melon-cotton-cotton-maize, cotton-maize-cotton-maize and cassava-maize-cotton-maize) including for each, four replications of three fertilizer treatments: recommended practice [150 kg ha -1 of 14-23-14 (NPK) plus 5S-1B, applied 25 days after sowing and 50 kg ha -1 of urea on 40 days after sowing], NPK-SB mixed with urea (the recommended amount of NPK-SB and urea are mixed then applied 40 days after sowing) and reduced NPK-SB dose (recommended practice, but the amount of NPK-SB is reduced to 100 kg ha -1). Prior cotton and subsequent maize yields and nutrient uptake were not significantly affected by fertilizer treatments. Furthermore, fertilizer treatments had no significant effect on soil chemical properties before planting the subsequent maize crop. Land use types had significant effect on cotton yields, soil chemical properties, subsequent maize yields and nutrient uptake. The lowest yield and nutrient uptake were registered in the cotton-maize-cotton-maize land use succession and the highest in the egusi melon-cotton-cotton-maize succession. For sustainable soil fertility management, adoption of adequate crop succession system and recommended fertilizer application practice are suggested.