Soil net nitrogen mineralization in the typical temperate grassland

Soil net nitrogen mineralization rate of three types temperate grassland in Inner Mongolia, China was studied using the resin-core technique. The major results include: the net nitrogen mineralization rate of the Stipa baicalensis meadow grassland, the Aneulolepidum Chinense grassland and the Stipa krylovii grassland were 0.333 kg · (hm² · d)^-1, 0.316 kg · (hm² · d)^-1 and 0.211 kg · (hm² · d)^-1 respectively during the field incubation period of July to October, 2005. Soil net nitrogen mineralization accumulation and rates were remarkably different between phase incubation and continuous incubation during the same field incubation period. Rainfall was one of the main factors affecting nitrogen mineralization. The net nitrogen mineralization rate was correlated with the change of soil moisture in all of the measured sites, the correlation coefficients were 0.80, 0.61 and 0.56