长期定位施肥与地膜覆盖对土壤肥力和生物学性质的影响

Effects of long-term fertilization and plastic film covering on some soil fertility and microbial properties

采集沈阳农业大学棕壤定位实验站(1987年设置)的土样,测定土壤pH、有机碳、全氮、碱解氮、速效磷、速效钾、微生物生物量碳、氮和BIOLOG碳源利用,结合地上部分生物量,系统分析了长期施肥与地膜覆盖对土壤肥力指标和微生物学性质的影响。结果表明,传统栽培条件下,土壤微生物群落平均吸光度(AWCD)与土壤有机碳含量、速效磷和有效钾显著相关(p<0.01),表明施肥通过影响有机碳和速效磷、钾含量影响微生物功能。在覆膜栽培条件下,AWCD与土壤pH和土壤碳氮比显著相关(p<0.01),表明覆膜通过影响土壤pH和土壤碳氮比影响微生物功能。覆膜引起玉米生育期的变化,影响有效碳的投入,从而直接影响土壤微生物功能。与相应的传统栽培相比,覆膜栽培后土壤pH的变化对微生物群落结构有一致影响。

Soil samples were collected from a long-term experiment site located at Shenyang Agricultural University initiated from 1987 and soil pH, organic carbon, total nitrogen, hydrolysable nitrogen, Olsen-P, available potassium, microbial biomass carbon and nitrogen, and average well color development （AWCD） of BIOLOG GN plate were analyzed to examine the complex effects of long-term fertilization and plastic film covering on some soil fertility and microbial properties. Results showed that under conventional cultivation, microbial function indicated by AWCD was affected by fertilization through its impacts on soil organic carbon, Olsen-P and available potassium contents, indicated by the significant correlations between AWCD and these indices （p 〈 0.01 ）. Compared to conventional cultivation, plastic film covering cultivation stimulated maize development and aboveground biomass, and changed soil pH and C/N ratio. Under the plastic film covering cultivation, AWCD was correlated significantly with soil pH and C/N ratio （p 〈 0.01 ）, but not significantly with soil organic carbon and Olsen-P contents （p 〉 0.05 ）, indicating that plastic film covering affected microbial function through its impacts on soil pH and C/N ratio.