[Effects of neem seed extracts on nitrogen use efficiency in two different soils].

Incubation test and pot experiments were conducted with haplic luvisols and hydragric anthrosols to study the effects of neem seed extracts (N I, N II) on nitrification and immobilization of ammonium sulfate. N I could significantly inhibit the nitrification of N applied to the two soils. N II was effective in promoting the immobilization of NH4+(-)N. Pot experiments showed that N II could increase the use efficiency of chemical nitrogen significantly in fimic anthrosols.