玉米秸秆还田对黑土微生物群落功能多样性的影响

为了解玉米秸秆还田对土壤微生物群落功能多样性的影响,采用ECO-Biolog微平板法,分析了以无玉米秸秆还田为对照(CK),6000 kg·hm^-2(S1)、9000 kg·hm^-2(S2)、12000 kg·hm^-2(S3)和15000 kg·hm^-2(S4)四个秸秆还田量的土壤微生物碳源代谢特征。结果表明:随着玉米秸秆还田量的增加,土壤微生物平均颜色变化率(AWCD)也随之增加,24~96 h的AWCD值变化迅速,96 h后进入平稳期,S4处理AWCD值始终大于其他处理;秸秆还田对Shannon指数与Simpson指数没有显著影响(P>0.05),但与CK相比,S4处理McIntosh指数显著增加了57.5%(P<0.05);主成分分析结果显示,秸秆还田影响着土壤微生物群落碳代谢能力,S1、CK、S2和S3处理在PC1和PC2上出现显著的分异,糖类、多聚物类、羧酸类碳源是研究区域内土壤微生物利用的主要碳源。因此,在东北黑土区增加玉米秸秆还田量能够提高土壤微生物对碳源的利用能力,提升黑土肥力。

Effects of corn straw return on functional diversity of microbial community in black soil

To explore the effects of corn straw return on functional diversity of soil microbial community, we investigated carbon metabolic characteristics of soil microorganisms by ECO-Biolog method, under four straw return rates including 6000 kg·hm^-2(S1), 9000 kg·hm^-2(S2), 12000 kg·hm^-2(S3) and 15000 kg·hm^-2(S4), with no straw return as control(CK). The results showed that the average well color development(AWCD) of soil microorganisms increased with the increasing rates of corn straw return, AWCD changed rapidly from 24 h to 96 h, and remained relatively stable after 96 h. The AWCD value of S4 treatment was higher than that in other treatments. There were no significant differences for both Shannon index and Simpson index after straw returning(P>0.05), but McIntosh index under S4 treatment was 57.5% higher compared with CK(P<0.05). Results of principal component analysis showed that straw returning affected carbon metabolism capability of soil microbial community, with significant difference among S1, CK, S2 and S3 treatments being found on the PC1 and PC2. Sugars, polymers and carboxylic acids were the main carbon sources used by soil microbes. Therefore, increasing the amount of corn straw returned to the field in the black soil area of Northeast China can improve the utilization capacity of soil microorganisms to carbon sources and improve soil fertility.