论文部分内容阅读
氮是蛋白质分子的主要构成元素,而一切生命又都以蛋白质为基础,蛋白质是一切生命组织必不可少的构成部分。土壤里几乎所有的氮都以有机氮的形式存在于土壤有机质(即在不同腐烂程度下的微生物细胞和动植物的残体)中。土壤有机质是土壤氮的贮存库。与相似的耕作土壤相比,草原土壤通常含有较多的有机氮(每公顷表土含2—5公吨)。当然有机氮的实际含量还是取决于土壤类型,土壤放牧期的长短、施肥的历史、管理措施和气候条件.
Nitrogen is a major component of protein molecules, and all life is based on protein, which is an integral part of all life organizations. Almost all of the nitrogen in the soil is present as organic nitrogen in the soil organic matter (ie, microbial cells and animal and plant debris at different degrees of decay). Soil organic matter is a reservoir of soil nitrogen. Prairie soils usually contain more organic nitrogen (2-5 mt of topsoil per hectare) than similar cultivated soils. Of course, the actual content of organic nitrogen is still dependent on the type of soil, the length of soil during the grazing period, the history of fertilization, management practices and climatic conditions.