有机无机肥配施提升冷浸田土壤氮转化相关微生物丰度和水稻产量

【目的】 以南方典型冷浸田为对象，研究化肥配施不同有机肥对冷浸田水稻产量以及土壤氮相关功能微生物群落丰度的影响，旨在为冷浸田土壤氮素活化和转化过程的定向调控，氮素利用效率提高及水稻高产施肥提供科学依据。 【方法】 通过连续 3 年 6 季的定位试验，采用土壤理化分析、酶学分析和荧光实时定量 PCR 技术深入探讨化肥配施不同堆肥原料有机肥对冷浸田养分活化、水稻产量提升及土壤氮相关功能微生物群落丰度的效应。本试验设 4 个处理，分别为单施化肥 (CK)、化肥配施猪粪 (PIM)、化肥配施牛粪 (CAM)、化肥配施鸡粪 (CHM)。 【结果】 CHM、CAM 处理水稻产量显著高于化肥处理( P < 0.05)，较 CK 平均增产 10.23%、7.62%。连续施用 CHM、CAM 显著提高了土壤 pH，增加了土壤有机碳、全氮和铵态氮含量。三种堆肥原料的有机无机配施均能够提高土壤氮素循环相关功能微生物基因丰度，其中细菌、古细菌总群落 16s rDNA 丰度和氨氧化古菌 (AOA) 和氨氧化细菌 (AOB) 的氨单加氧酶 ( amoA) 基因丰度提高趋势一致，以 CHM 处理最高，但细菌总群落 16s rDNA 丰度增幅较小。亚硝酸盐还原酶 ( nirK、 nirS) 基因和一氧化二氮还原酶 ( nosZ) 基因丰度对不同处理的响应并不一致。相关性分析表明，土壤有机碳和全氮含量是影响 AOA、AOB、 nirK、 nirS 型反硝化细菌的重要因子。 【结论】 化肥配施鸡粪有机肥能显著提高冷浸田土壤铵态氮、速效磷含量，增加细菌、古菌、AOA 和 AOB 氨单加氧酶 ( amoA) 的基因丰度，增强土壤脲酶、蛋白酶和磷酸酶的活性，提升冷浸田土壤生产力。

Combined application of inorganic and organic fertilizers improve rice yield and the abundance of soil nitrogen-cycling microbes in cold waterlogged paddy fields

Objectives]Taking the typical cold waterlogged paddy fields in the South China as a research object, the effects of chemical fertilizers combined with different manures on the grain yield of paddy rice and the abundance of soil nitrogen-cycling microbes were compared. The study could provide scientific basis for the theory and practice of nitrogen mobilization, nitrogen redirection control and use efficiency, and fertilizer application scheme for high yield in cold waterlogged fields.Methods]A three year-study was conducted to analyze the influences of the fertilizers combined with different organic manures on nutrient mobilization, rice yield and the abundance of nitrogen-cycling bacteria in cold waterlogged soils on the basis of soil properties, enzymatic characteristics and real-time quantification PCR. The field experiment included four treatments:chemical fertilizers (CK), chemical fertilizers combined with pig manure (PIM), chemical fertilizers combined with cattle manure (CAM) or chemical fertilizers combined with chicken manure (CHM).Results]The grain yields responded positively to both CHM and CAM application, and were increased by 10.2% and 7.6% over the yield of CK, respectively. The soil pH, organic carbon, total nitrogen content and ammonium nitrogen content were all increased after continuous application of CHM or CAM. The abundance of microbial genes related to soil nitrogen-cycling was significantly enhanced by the additions of the three fertilizer formulations. Furthermore, the 16s rDNA abundance of bacteria and archae bacteria, andamoA(ammonia monooxygenase) abundance of ammonia-oxidizing archaea (AOA) and anaerobic oxidizing bacteria (AOB) presented consistent increasing patterns, and the highest abundances were exhibited in the CHM-treated soil and the increase rate of bacteria 16s rDNA was smaller than others. However, the gene abundances of nitrite reducate (nirK,nirS) and nitrous oxide reducate (nosZ) responded differently to the fertilizer formulations. Correlation analysis showed that the contents of soil organic carbon and total nitrogen appeared to be the key factors influencing the abundance and diversity of AOA-, AOB-,nirK-andnirS-type denitrifying bacteria.Conclusion]The application of the fertilizers combined with chicken manure could significantly increase the contents of soil ammonium nitrogen and available phosphate, improve the gene abundances of bacteria, archaebacteria, AOA and AOB-typeamoAand enhance the activities of soil urease, protease and phosphatase, thereby improving the productivity of cold waterlogged soils.