冬季作物对稻田土壤微生物量碳、氮和微生物熵的短期影响

研究不同的冬季作物马铃薯、黑麦草、紫云英、油菜在"冬季作物-双季稻"轮作种植制度下短期内对稻田土壤微生物碳、氮和微生物熵的影响,在湖南省土壤肥料研究所的实验网室内设置了小区试验.试验结果表明:几种冬季作物均提高了稻田土壤微生物碳、氮含量,黑麦草明显提高了土壤微生物量碳和微生物熵,紫云英明显提高了土壤微生物量氮.冬季作物对土壤微生物量碳和土壤微生物量氮的季节性影响变化趋势基本一致,紫云英、马铃薯处理的土壤微生物量C、N含量均在水稻生育期间8月中旬达到最大值.

Short-term influences of winter crops on microbial biomass carbon, microbial biomass nitrogen and Cmic-to-Corg in a paddy soil

Winter crop-rice-rice is an important cropping system in rice production region of Hunan Province. The selection of an appropriate winter crop that is beneficial to rice crop and paddy soil is critical to sustainable crop production. The objective of this study was to investigate the effects of selected winter crops on soil microbial biomass carbon, microbial nitrogen and Cmic-to-Corg in a reddish paddy soil, using an experiment initiated in 2004. The winter crops included potato, ryegrass, Chinese milk vetch, and rape seed, and fallow was used as control. The results indicated that under winter crops soil microbial biomass C and microbial N were relatively higher than under fallow. Ryegrass significantly increased soil microbial biomass C and Cmic-to- Corg, Chinese milk vetch significantly increased soil microbial biomass N, and the trends of soil microbial biomass C and N during rice growth seasons were similar among different crops. Soil microbial biomass C and microbial N under Chinese milk vetch and potato reached the maximum in mid-August.