蚯蚓粪对豇豆根际土壤生物学特征及微生物活性的影响

Effects of vermicompost on biological characteristics and microbial activity in rhizosphere soil of cowpea

通过大田试验,研究CK(对照,不施肥)、CF(单施化肥)、VC(蚯蚓粪)和VC+CF(蚯蚓粪和化肥各提供50%的氮)处理对豇豆根际土壤微生物数量、微生物量碳、根系分级、根系分泌物、微生物呼吸及代谢熵的影响。结果表明:与CF处理相比,VC+CF处理显著增加了根际土壤微生物数量与微生物量碳,其中细菌数分别较CK,CF和VC处理增加124.13%,70.48%和17.83%。施用蚯蚓粪明显促进了豇豆根系的生长,尤其增加了毛细根的数量及在根体系中的比例。同时,VC+CF处理还显著提高了根际土壤中根系分泌物含量,并增强了土壤微生物呼吸作用,但降低了代谢熵,其中,土壤微生物呼吸分别比CK,CF和VC处理增加64.91%,36.23%和16.05%,而代谢熵分别下降10.85%,9.06%和5.32%。与VC+CF处理相比,VC处理对豇豆根际土壤微域的影响较小。综上,施用蚯蚓粪相比单施化肥能明显改善豇豆根际土壤的微生态环境,且能显著增强土壤微生物活性,尤以蚯蚓粪与化肥配施的效果更优。

A field experiment including 4 treatments,CK（ neither urea nor vermicompost was applied）,CF（ 100%of nitrogen was provided by urea）,VC（ 100% of nitrogen was provided by vermicompost）,and VC ＋ CF（ 50% and50% of nitrogen was provided by vermicompost and urea,respectively） was performed,to determine the effects of different treatments on microbial population,microbial biomass carbon content,root system construction,root exudates content,microbial respiration and metabolic quotient in the rhizosphere soil of cowpea. It was shown that in comparison with CF treatment,VC ＋ CF treatment significantly increased microorganism population and microbial biomass carbon content. Bacteria population under VC ＋ CF treatment was increased by 124. 13%,70. 48% and17. 83% compared to that under CK,CF and VC treatment,respectively. Vermicompost application obviously promoted the root growth and construction of cowpea,especially fine root weight and the ratio of fine root. Meanwhile,VC ＋ CF treatment evidently increased the root exudates content and significantly increased microbial respiration,butthe metabolic quotient was decreased. Microbial respiration under VC ＋ CF treatment was increased by 64. 91%,36. 23% and 16. 05% compared to that under CK,CF and VC treatment,respectively,while the metabolic quotient was reduced by 10. 85%,9. 06% and 5. 32%,respectively. However,the effect of VC treatment on micro-domain environment characteristics was minor. In conclusion,vermicompost application could significantly improve micro-ecological environment and enhance the microbial activity of cowpea rhrizosphere soil compared with CF treatment,especially when vermicompost was co-applied with inorganic fertilizer.