长期施肥对红壤微生物生物量碳氮和微生物碳源利用的影响

Effects of long-term fertilization on microbial biomass carbon and nitrogen and on carbon source utilization of microbes in a red soil

采集湖南省祁阳县红壤长期定位施肥19年的土壤样品,分析长期不同施肥红壤的微生物生物量碳、氮和微生物碳源利用率,以揭示长期施肥对红壤微生物学性状的影响.结果表明:施肥19年后,有机肥单施或与化肥配合施用均显著提高土壤微生物生物量碳、氮和微生物碳源利用率.单施有机肥的土壤微生物生物量碳、氮含量分别为231和81mg·kg-1,化肥有机肥配施分别为148和73mg·kg-1,均显著高于化肥配施秸秆、不施肥和单施化肥;施用有机肥和化肥配施秸秆的土壤微生物生物量氮占全氮的比例平均为6.0%,显著高于单施化肥和不施肥.Biolog-ECO分析中,平均吸光值(AWCD)的大小为:化肥有机肥配施、单施有机肥>对照>单施化肥、化肥配施秸秆.单施有机肥或与化肥有机肥配施增加了红壤微生物对碳水化合物、羧酸、氨基酸、聚合物、酚类和胺类的碳源利用率;化肥配施有机肥的红壤微生物对聚合物类碳源利用率最高,化肥配施秸秆的红壤微生物对碳水化合物类碳源的利用率最高.表明施用有机肥能显著提高红壤的微生物生物量碳、氮和微生物碳源利用率,提高红壤肥力,保持作物高产.

In order to explore the effects of long-term fertilization on the microbiological characters of red soil,soil samples were collected from a 19-year long-term experimental field in Qiyang of Hunan,with their microbial biomass carbon（MBC） and nitrogen（MBN） and microbial utilization ratio of carbon sources analyzed.The results showed that after 19-year fertilization,the soil MBC and MBN under the application of organic manure and of organic manure plus inorganic fertilizers were 231 and 81 mg·kg-1 soil,and 148 and 73 mg·kg-1 soil,respectively,being significantly higher than those under non-fertilization,inorganic fertilization,and inorganic fertilization plus straw incorporation.The ratio of soil MBN to total N under the application of organic manure and of organic manure plus inorganic fertilizers was averagely 6.0%,significantly higher than that under non-fertilization and inorganic fertilization.Biolog-ECO analysis showed that the average well color development（AWCD） value was in the order of applying organic manure plus inorganic fertilizers ≈applying organic manure non-fertilization inorganic fertilization ≈ inorganic fertilization plus straw incorporation.Under the application of organic manure or of organic manure plus inorganic fertilizers,the microbial utilization rate of carbon sources,including carbohydrates,carboxylic acids,amino acids,polymers,phenols,and amines increased;while under inorganic fertilization plus straw incorporation,the utilization rate of polymers was the highest,and that of carbohydrates was the lowest.Our results suggested that long-term application of organic manure could increase the red soil MBC,MBN,and microbial utilization rate of carbon sources,improve soil fertility,and maintain a better crop productivity.