施肥对黄土丘陵区土壤养分及微生物群落结构的影响

Effects of Fertilization on Soil Nutrients and Microbial Community Structure in Loess Hilly Region

为探究黄土丘陵区耕作土壤养分与土壤微生物群落间的相互作用机制,本试验采用磷脂脂肪酸(PLFA)法研究了不同施肥处理[种植作物不施肥(CK)、单施有机肥(M)、氮磷肥配施(NP)、氮磷钾肥配施(NPK)和有机肥配施氮磷肥(MNP)]对土壤养分和微生物群落结构的影响以及他们之间的相互关系。结果表明,土壤养分对微生物群落的影响因施入肥料种类不同而存在差异。不同施肥处理显著影响土壤养分含量,其中CK和化肥处理下土壤养分含量低于M或MNP处理;施肥处理通过提供土壤微生物所需的营养物质显著影响微生物群落结构,其中M处理尤其是MNP处理下土壤微生物群落结构较CK、NP、NPK处理均发生显著改变,MNP处理可增加细菌、放线菌生物量和微生物总生物量,降低革兰氏阳性菌/革兰氏阴性菌、真菌/细菌的值,提高微生物养分利用能力以及群落的多样性。本研究结果可为黄土丘陵区培肥土壤以及农田生态管理模式的探索提供科学依据。

In order to explore the interaction mechanism between cultivated soil nutrients and soil micro-bial communities in the Loess Hilly Region,the phospholipid fatty acid(PLFA)method was used to study the effects of five fertilization treatments,including no fertilizer(CK),organic fertilizer(M),nitrogen and phos-phorus fertilizers(NP),nitrogen,phosphorus and potassium fertilizers(NPK)and organic fertilizer com-bined with nitrogen and phosphorus fertilizers(MNP),on soil nutrients and microbial community structure and their relationships.The results showed that the effects of soil nutrients on microbial communities were dif-ferent with different fertilization treatments.The contents of soil nutrients were significantly affected by different fertilization treatments,and those under CK and chemical fertilizer treatments were lower than those under M and MNP treatments.Fertilization treatments could significantly affect the microbial community structure by providing nutrients for soil microorganisms.The soil microbial community structure under M treatment,especially MNP treatment,had significant changes compared with CK,NP and NPK treatments.MNP treatment could increase the biomass of bacteria,actinomycetes and total microbial biomass,reduce the ratio of Gram-positive to Gram-negative bacteria and the ratio of fungi to bacteria,improve the microbial nutrient utilization capacity,and increase the community diversity.In conclusion,the results of this study could provide ascientif-ic bases for increasing soil fertility and developing farmland ecological management model in the Loess Hilly Region.