ISSN 2360-798X
Abstract
Accepted 25th July, 2014
Low fertility level of soil is among the major constraints of crop production in Nigerian savannah. Field trails were therefore conducted during 2008 and 2009 cropping seasons to evaluate the potentials of neem seed cake (NSC)- a residues obtained after oil extraction from the seed of neem tree (Azadiracta indica)- in combination with NPK fertilizers for sustained productivity of maize. Three levels (0, 2 and 4) tons ha-1of NSC and that of NPK fertilizers (0, ¼ and ½ optimum fertilizer recommendation (OFR) for maize in Samaru-Zaria, Nigeria) were solely applied and in combination using randomized complete block design in 12m2plots with three replication. OFR (120:60:60 NPK) and recommended rate (NRR) for combined NSC and inorganic fertilizers (4:1) were included as checks. The plots were managed manually and monitored for growth parameters, at harvest yield parameters were measured, and plant and soil were sub-sampled for analysis. Result showed that combination of NSC and NPK significantly (p<0.005) increased maize number of leaves and sterm girth as well as leaf area and height (p<0.001). Significant increased (p<0.001) were also recorded on maize grains yield, stover yield total dry matter yield and relative yield increase also, maize harvest index was significantly (p<0.005) higher from the treated plots compared to control. No significant increase was found on maize N, P and K concentration however, N and P uptake from the treated plots were higher (p<0.005) than control. Result also showed no significant improvement on some selected soil properties after cropping nonetheless, NSC can still serve as good choice organic amendment. Combine application 4 tons ha-1NSC + ¼ OFR was significantly higher in all the growth and yield parameters monitored and statistically similar with 2 tons ha-1NSC + ¼ OFR except for stover yield therefore, application of 2 tons ha-1NSC + ¼ OFR was recommended considering the economic level of the farmers and cost of inorganic fertilizers in the study area. Further research should also be conducted to explore the full potentials of NSC
Keywords: neem seed cake, inorganic fertilizers, Alfisols, productivity