根际土壤微生物量氮周转率的研究

用15N示踪法研究了不同植物对根际及非根际微生物量氮周转率的影响。结果表明 ,不同植物对微生物量氮周转率的影响不同。栽种豆科植物三叶草由于其根系分泌物中的含氮有机物含量较高 ,所以土壤中微生物量氮的周转率快于栽种黑麦草。两种植物根际土壤的微生物量氮的周转率都快于非根际土壤 ,与土壤蛋白酶活性的研究结果一致

TURNOVER OF MICROBIAL BIOMASS IN RHIZOSPHERE SOILS OF CLOVER AND RYEGRASS

The turnover rate of microbial biomass nitrogen in the rhizosphere of clover (Trifolium prafensel) and ryegrass ( Lolium perence) was investigated with 15 N isotopic technique. The results showed that the activity of soil protease was higher in rhizosphere during the growth period of clover and ryegrass. It also indicated that the activity of soil protease of clover was higher than that of ryegrass. Turnover rate of biomass 15 N was in the following order:root zone>0～2mm>15～25mm>25～40mm. It is suggested that the principal function of microbe in rhizosphere is to accelerate the nutrient cycling compared to nonrhizosphere soil.