Calculation of N Mineralization from Six Green Manure Legumes under Field Conditions from Autumn to Spring

Publisher Website
Google Scholar
Abstract
Mean soil temperature values and optimal moisture conditions were incorporated into a kinetic first-order model to describe net nitrogen mineralization from above-ground legume material under field conditions. Calculations showed that red clover, persian clover and egyptian clover would mineralize 1 to 2 kg N ton-1 above-ground legume dry matter from autumn to early spring, whereas white clover, black medic and subterranean clover would mineralize between 6 and 13 kg N ton-1 of dry matter during the same time period. Late ploughing (December 1) compared to early ploughing (October 15) had a substantial effect on the initial amounts of N released but differences decreased and were small in May. Assuming an above-ground legume biomass of 3 tonnes of dry matter, up to 40 kg N per hectare can be mineralized from autumn to early spring depending on the legume species. The species had a larger influence on the mineralized amounts of N than the location and the time of ploughing.