Field trials were conducted to examine the responses of Cassava, Maize and Pepper to fertilizers in the alleys of 3, 4 and 6 years oil palm fields. Fertilizers: NPK (1.44 kg/plot), Ferti Plus (9.68 kg/plot) and poultry manure (6.17 kg/plot) were applied two weeks after planting. Results showed that fertilizers significantly influenced N uptake and some indicators of N use efficiencies measured. NPK enhanced uptake and apparent recovery of N and Ferti Plus (organo-mineral fertilizer) and poultry manure promoted agronomic and physiological efficiencies of N use. Uptake and yields of N were higher for sole crops compared with intercrops across the fertilizers. Cassava and maize had enhanced N removed at harvest, Internal utilization efficiency (IE) and apparent recovery efficiency (RE), and pepper had higher IE, Apparent Recovery Efficiency (RE), Agronomic and Physiological Efficiency (PE) of N use. Age of oil palm fields and fertilizers influenced nutrient uptake and use efficiencies of the alley intercrop species. Nitrogen uptake and use efficiencies were highest for 4 and 6 years compared with the 3 years old fields across the intercrop species. NPK and Ferti Plus had higher efficiencies of uptake and use of N compared with poultry manure across the ages of oil palm fields. It is concluded that, alley intercrop species differed in uptake and use efficiencies of N. The alleys of oil palm of 1 to 6 years supported the performance of intercropped arable species and fertilizers enhanced soil nutrients and crop yields.

The oil palm (Elaeis guineensis Jacq), is a crop of tremendous food, nutrition and economic importance in the tropics. Weather variability and extremes profoundly impact the establishment, survival and productivity of oil palm on the field. Alleys of palm trees in plantation are cropped with arables during early years following field establishment. Studies were conducted at the Nigerian Institute for Oil Palm Research, Benin City, Nigeria. Oil palm seedlings responded to shading, irrigation and AMF inoculation via enhanced water use efficiency, growth vigor and reduced seedling mortality in the nursery during dry season. Age of oil palm and intercrops of Cassava, Maize and Pepper affected mixture productivity and competitive functions in alleys of 2 to 6 years old oil palm fields. Fertilizers (inorganic/organic) promoted agronomic and physiological efficiencies of N use by alley species. Sole crops had higher N use efficiency compared with the intercrops across the fertilizers.