Impact of application of neem leaves and poultry manure on nutrient dynamics of a Haplic Acrisol

Abstract A 12-week incubation study of a Haplic Acrisol amended with ground neem leaves (Azadirachta indica Adr. Juss.) (20, 40, 60, 80 and 100 t h−1) plus 10 t h−1 poultry manure in pots were carried out at the Technology Village of the University of Cape Coast, Ghana, to assess the changing patterns of NH4 +[sbnd]N, NO3 −[sbnd]N and available P. The study lasted for 12 weeks starting from 17 April 2004. The peak of release of NH4 +[sbnd]N occurred at the 2nd week after incubation of samples; the peak of release of the available P occurred also at the 2nd week and the NO3 −[sbnd]N occurred at the 4th week. The production of NH4 +[sbnd]N and available P had proportional relationships with the quantity of neem leaves and poultry manure incorporated into the soil. The amount of NO3 −[sbnd]N produced was not proportional to the quantity of the neem leaves and the poultry manure as above. The higher levels of the neem leaves (100 t, 80 t and 60 t) plus the poultry manure produced lower cumulative values of NO...