长期不同施肥土壤微生物态氮作为土壤供氮指标的研究

Study on soil microbial nitrogen (SMB-N) as an index of soil N supply in long-term experiment

选用中国农业大学昌平试验站长期定位试验中１４个不同施肥处理的土壤，测定冬小麦播种前和收获后土壤微生物态氮含量以及小麦吸氮量，探讨了不同施肥处理土壤微生物态氮含量的差异以及土壤微生物态氮含量作为土壤潜在供氮指标的可行性。结果表明：施用有机肥增加了土壤微生物态氮的数量，与不施有机肥的处理相比差异达显著水平（Ｐ＜０.０５）；增施氮肥，微生物态氮的数量也随之增加，且处理间差异多数达显著水平（Ｐ＜０.０５）；高氮情况下，施用磷、钾肥对土壤微生物态氮的数量影响不大；经相关分析，播前土壤微生物态氮含量与小麦生物量产量（ｒ=０.９１８）和吸氮量（r=０．９１４）呈显著正相关关系，表明盆栽条件下，播前土壤微生物态氮的含量可作为土壤潜在供Ｎ能力的指标之一。

The fourteen different treatments were carried out at long-term experiment in Changping experimental station of China Agricultural University. The contents of the soil microbial nitrogen (SMB-N) of pre-sowing and post-harvesting and uptaking-N of wheat were measured. The differences of SMB-N and the content of SMB-N as feasibility of soil potential-N supply, were also investigated. The results indicated that using manure increased SMB-N and the differences among these treatments achieved significant levels (P<0.05). With high nitrogen condition the SMB-N were less effected by using P and K fertilizers. There were significant relationships between the SMB-N and biomes of wheat (r=0.918) and its uptaking-N (r=0.914). The SMB-N before sowing might be regarded as one of the indices of soil potential N supply at pot culture.