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采用磷脂脂肪酸法通过田间试验研究氮添加对银杏人工幼龄林土壤有机碳化学组分、微生物生物量与群落结构的影响,施氮水平设置为0 kg·hm-2a-1N(对照),50 kg·hm-2a-1N(低氮),100 kg·hm-2a-1N(中氮)及150kg·hm-2a-1N(高氮),试验周期为1年。结果表明:高氮处理显著降低土壤有机碳含量及氧烷基碳组分但增加烷基碳与氧烷基碳比值。不同施氮水平对土壤微生物量及群落结构的影响不同,总体上中、高氮处理显著影响土壤微生物量与群落结构组成。中、高氮处理显著降低土壤微生物生物量碳含量但增加土壤微生物生物量氮含量,同时显著降低土壤总微生物量、真菌生物量及细菌生物量;而且中、高氮处理显著降低革兰氏阳性菌的相对丰度,但增加真菌细菌比和放线菌的相对丰度。另外,高氮处理显著降低土壤pH及土壤呼吸。
Phospholipid fatty acid method was used to study the effects of nitrogen addition on soil organic carbon chemical composition, microbial biomass and community structure in young Ginkgo biloba forest. The nitrogen level was set at 0 kg · hm-2a-1N (control) kg · hm-2a-1N (low nitrogen), 100 kg · hm-2a-1N (medium nitrogen) and 150kg · hm-2a-1N (high nitrogen). The test period was 1 year. The results showed that high N treatment significantly decreased soil organic carbon and oxygen alkyl carbon components but increased the ratio of alkyl carbons to alkyl carbons. The effects of different N rates on soil microbial biomass and community structure were different. Generally, medium and high N treatments significantly affected soil microbial biomass and community structure. Medium and high nitrogen treatments significantly decreased soil microbial biomass carbon but increased soil microbial biomass nitrogen, while significantly decreased soil total microbial biomass, fungal biomass and bacterial biomass; and medium and high nitrogen treatments significantly reduced Gram-positive The relative abundance of bacteria, however, increases the relative abundance of fungal bacteria and actinomycetes. In addition, high N treatment significantly decreased soil pH and soil respiration.