不同碳氮比有机肥对有机农业土壤微生物生物量的影响

Effects of organic manures with different carbon-to-nitrogen ratios on soil microbial biomass of organic agriculture

  • 摘要: 有机肥能提高土壤微生物活性, 改善土壤品质。碳氮比是影响有机肥肥效的重要因素。本试验以无肥处理为对照(CK), 设置4个有机肥碳氮比处理(20︰1、15︰1、10︰1、5︰1), 在温室中进行茄子盆栽试验, 定期采集土壤样品, 用熏蒸提取法测定土壤微生物生物量碳(SMBC)、氮(SMBN), 研究等氮条件下不同碳氮比有机肥料对土壤生物活性的影响。试验结果表明, 不同碳氮比的有机肥均能提高土壤的SMBC和SMBN含量, 具体表现为SMBC: 20︰1>10︰1≈15︰1>5︰1>CK, SMBN: 15︰1>10︰1>20︰1>5︰1>CK。SMBC/SMBN的比率反映土壤氮素生物活性, 其值越低, 生物活性越大, 氮素损失越少, 本试验SMBC/SMBN表现为: 15︰1<10︰1<20︰1≈5︰1 

    Abstract: It was possible to increase soil microbial activity and improve soil quality by using organic fertilizers. Carbon-to-nitrogen ratio is critical for high efficiency of organic fertilizer. A pot experiment was conducted to determine the effects of organic fertilizers with different carbon-to-nitrogen ratios on soil microbial biomass at the same level of nitrogen. Of the five treatments used in the study, four received organic manure in different carbon-to-nitrogen ratios (20︰1, 15︰1, 10︰1 and 5︰1) and another was non fertilizer treatment (CK). The results showed that all of the treatments with organic fertilizers increased soil contents of microbial biomass C and N. The order of soil microbial biomass C content for different treatments was 20︰1 > 10︰1 ≈ 15︰1 > 5︰1 > CK. Also the order of soil microbial biomass N content for different treatments was 15︰1 > 10︰1 > 20︰1 > 5︰1 > CK. The soil microbial biomass C/N reflected soil nitrogen biological activity. The order of soil microbial biomass C/N for different treatments was 15︰1 < 10︰1 < 20︰1 ≈ 5︰1 < CK. This suggested that organic manures with 15︰1 or 10︰1 carbon-to-nitrogen ratios improved biological activity of soil nitrogen and decreased nitrogen loss. Although soil microbial biomass was high under fertilization of organic manure with a high (20︰1) carbon-to-nitrogen ratio, biological activity of soil nitrogen was low. Soil microbial biomass was low under treatment of organic manure with a low (5︰1) carbon-to-nitrogen ratio. The study laid the theoretical and practical bases for the scientific use of organic manure in organic agriculture.

     

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