三江平原岗地白浆土水解酶活性和动力学特性对不同连作农作物的响应

作物种植会对农田生态系统产生一定的影响。大田试验条件下,在黑龙江省853农场岗地白浆土上连续6年种植玉米、大豆、小麦、水稻,研究了土壤理化性质以及土壤中与碳、氮、磷、硫元素转化相关的9种水解酶活性和动力学特性的响应;同时研究了不同作物种植对土壤脲酶、磷酸单酯酶、磷酸二酯酶、芳基硫酸酯酶及β-葡糖苷酶动力学特性的影响。结果表明,大豆连作土壤的有效氮、总碳、总氮、总磷和总硫含量都稍高;大豆处理土壤pH值略低,但其它三种作物种植下的土壤均呈微酸性,差异不显著。土壤水解酶动力学参数对种植作物的反应与表观活性的反应不一致。玉米连作土壤蛋白酶和磷酸单酯酶活性高于其它处理;小麦处理的磷酸二酯酶和芳基硫酸酯酶活性最高,水稻连作土壤蛋白酶、磷酸二酯酶和磷酸三酯酶活性最低。连年种植小麦处理的土壤脲酶、磷酸二酯酶以及芳基硫酸酯酶Vmax显著高于其它处理,小麦连作土壤β-葡萄糖苷酶、脲酶、磷酸二酯酶和芳基硫酸酯酶的Vmax/Km值显著高于其它处理,可以看出在此处理下土壤酶具有较强的催化潜势。

Effects of Different Continuous Cropping on Soil Enzyme Activities of Hilly Albic Soil

Cropping systems influence the ecology of agricultural soils. The object of this study was to determine how continuous cropping systems (Soybea, Corn, Wheat, Rice) affected soil hydrolase activities and kinetic properties. Agricultural fields in albic soil of Heilongjiang Province within soil type and location so that each set contained one field managed for annual crops using conventional tillage. Nine enzymes related to carbon, nitrogen, phosphorus and sulfur availability(β-galactosidase, α-galactosidase, β-glucosidase, α-glucosidase, urease, protease, phosphomonoesterase, phosphodiesterase, arylsulphatase) were examined in 0-20 cm soil samples. We determined five enzymes kinetic parameters, including β-glucosidase, urease, phosphomonoesterase, phosphodiesterase and arylsulphatase. In present study, Soil Available N, Total C, Total N, Total P and Total S were greater under soybean cultivation, while most enzyme activities and kinetic parameters were highest under wheat cultivation. Soil phosphodiesterase and arylsulphatase activity and Vmax of soil urease, phosphodiesterase and arylsulphatase were significantly highest under wheat cultivation. Vmax/Km values of soil β-glucosidase, urease, phosphodiesterase and arylsulphatase under wheat cultivation were highest. Data showed that wheat cropping in albic soil of Jiansanjiang plain has enhanced soil enzyme activities and kinetical parameters.