外加碳、氮对土壤氮矿化、固定与激发效应的影响

本文利用14C和15N对中国生黄绵土(坡地黄绵土)、菜园黄绵土和瑞典耕作草甸土的土壤氮矿化、固定与激发效应进行了研究。结果表明,外加碳、氮能促进土壤氮的矿化、固定与激发效应;促进作用的大小次序为外加NH4-15N大于外加NO3-15N,外加葡萄糖+NH4-15N大于外加葡萄糖+NO3-15N,外加麦秸+NH4-15N大于外加麦秸+NO3-15N,外加葡萄糖+NH4-15大于外加麦秸+NH4-15,外加葡萄糖+NO3-15N大于外加麦秸+NO3-15N;低肥力土壤高于高肥力土壤。在本文中提出了土壤净矿化氮的激发效应、土壤生物固定氮激发效应和土壤总矿化氮的总激发效应的概念,认为土壤氮的总激发效应更能反映土壤氮激发效应的实质。

Effect of supplying C and N on the mineralization, immobilization and priming effect of soil nitrogen

The mineralization, immobilization and priming effect of soil N in raw loessial soil, garden loessial soil and Swedish cultivated meadow soil were studied by using the incubation method with adding glucose-¹⁴C, straw-¹⁴C, NH₄-¹⁵N and NO₃- ¹⁵N. The main results obtained were as follows: 1) The added C and N could stimulate the mineralization, immobilization and priming effect of soil N. 2) The intensity of stimulation by added C and N was added NH₄-¹⁵N > added NO₃-¹⁵N, added glucose plus NH₄-¹⁵N > added glucose plus NO₃-¹⁵N, added straw plus NH₄-¹⁵N > added straw plus NO₃-¹⁵N, added glucose plus NH₄-¹⁵N > added straw plus NH₄-¹⁵N, and added glucose plus NO₃-¹⁵N > added straw plus NO₃-¹⁵N. 3) The priming effect in impoverished soil was higher than that in fertile soil. The concepts of priming effect of soil net mineralization N, priming effect of soil immobilization N and total priming effect of total soil mineralization N were put forward in this paper. It was considered that the total prime effect of total soil mineralization N could reflect the nature of priming effect of soil N.