不同土壤类型和农业用地方式对土壤微生物量碳的影响

Effects of soil type and land use pattern on microbial biomass carbon

通过野外调查与室内分析,研究了山东桓台县3种土壤类型(潮土、褐土和砂姜黑土)与农业用地方式(林地、菜地和粮田)对土壤表层(0—10 cm)微生物量碳的影响。结果表明,不同农业用地方式对微生物量碳的影响较大,3种利用方式的微生物量碳含量差异显著,依次为:粮田>菜地>林地;土壤类型不同,土壤微生物量碳含量也不相同。任何一种土壤,菜地的N、P、K含量都高于粮田和林地;有机质含量粮田>菜地>林地;pH值林地>粮田>菜地。全N、有机质与土壤微生物量碳呈极显著正相关,有效P与微生物量碳呈弱负相关,速效K、pH值和微生物量碳不相关。不同用地方式下土壤养分与微生物量碳的相关程度不同。秸秆还田和施用有机肥有利于提高土壤中微生物量碳水平,施用化肥在一定程度上能够增加微生物量碳。

Soil microorganism plays an important role in material cycling and energy transformation of an ecosystem. Due to its sensitivity to environmental changes, soil microorganism is considered to be one of the key indicators to reflect the variation of soil quality. In this paper, field investigation and lab experiment analysis were carried out to study microbial biomass carbon （MBC） in surface soil （0-10 cm） in Huantai County, Shandong Province. Three soil types （Fluvoaquic soil, Cinnamon soil and Sajiang black soil） and agricultural land use patterns （forest, vegetable and crop lands） were included in this study. Results showed that there were significant difference between MBC responded to different land use patterns, which increased in the order of crop land （440-480 mg/kg） 〉 vegetable land （320-380 mg/kg） 〉 forest land （240-330 mg/kg）. MBC contents varied between different soil types, however, compared to agricultural land use pattern, the impact of soil type on the MBC was much less pronounced. For any type of soil, the content of N, P and K of vegetable land was higher than those of forest and crop lands; organic matter content of crop land was the highest, followed by vegetable and forest lands; and soil pH of vegetable land was lowest, followed by crop and forest lands. In addition, MBC had a significant positive correlation with total nitrogen （TN） and organic matter （ P 〈 0.01 ）. There was a significant but weakly negative correlation between MBC and available phosphorus （AP） （ P 〈 0.05）; whereas, there was no correlation between MBC and available potassium （AK） and pH. The correlativity between soil nutrients and MBC under different land use patterns was not consistent. Returning straw to field and applying organic fertilizer had a favorable effect on the soil MBC.