Microbial, Urease Activities and Organic Matter Responses to Nitrogen Rate in Cultivated Soil

Abstract

Nitrogen (N) fertilizer is an important field management, this paper was to investigate the responses of microbial activity measured by microcalorimetric technique, urease activity and organic matter to proper nitrogen (N) fertilizer in cultivated system in the North China Plain. The microcalorimetry results showed that microorganisms under proper N fertilizer rate got the efficient metabolism. The maximum heat production (Pmax) of microcalorimetry parameter implied that increasing the N fertilizer rate, Pmax did not increase always but firstly increased than decreased. In addition, from soil urease activity and organic matter studies, high soil urease activity due to both N fertilizer rate and growth stage and these had light influence on soil organic matter. These results suggest that only proper amount of N fertilizer rate and suitable topdressing for a good wheat-growing environment.