不同种植方式对苗期大豆、玉米根际土壤酶活性及微生物量碳、氮的影响

摘要

Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon and nitrogen was studied. Nine treatments were set and maize, soybean, soy-maize were planted in pots filled with cropped soils of soybean, maize or mixed cropping, respectively. Result showed that: ①Soil urease and polyphenol oxidase activities of soy-maize rotation increased than that of soybean continuous cropping; and only urease activity increased than maize continuous cropping, but catalase activity decreased, and invertase activity did not changed significantly. ② Soil urease activity of soy-maize mixed cropping was higher, but invertase activity was lower than that of soybean or maize continuous cropping, and polyphenol oxidase activity was not significantly changed. In the soil of cropped maize, soil catalase activity of soybean and maize mixed cropping was significantly lower than that of monocropping of soybean or maize. ③Soil microbial biomass carbon and nitrogen of soybean and maize continuous cropping was higher than that of soybean and maize rotation. In the soil of cropped maize, soil microbial biomass nitrogen of soybean and maize mixed cropping was significantly higher than that of monocropping of soybean or maize. ④Soil microbial biomass carbon and nitrogen and C/N ratio had a significant or very significant correlation with soil catalase activity and polyphenol oxidase activity, respectively. Therefore, different cropping patterns could affect rhizosphere soil enzyme activities and influence soil microbial biomass carbon and nitrogen, but the variation trends were different.%　　通过盆栽试验的方法,研究不同种植方式对苗期大豆、玉米根际土壤脲酶、过氧化氢酶、多酚氧化酶和蔗糖酶活性和微生物量碳、氮的影响,试验共设9个处理,分别在前茬作物为大豆、玉米和大豆-玉米混作的土壤上种植大豆、玉米和大豆-玉米混作.结果表明,①与大豆-玉米轮作相比,大豆连作降低了根际土壤多酚氧化酶和脲酶活性,玉米连作降低了脲酶活性而提高了过氧化氢酶活性,三种种植方式下蔗糖酶活性无显著差异.②与大豆-玉米混作相比,大豆连作和玉米连作都降低了根际土壤脲酶活性,提高了根际土壤蔗糖酶的活性,根际土壤多酚氧化酶的活性变化不明显.在前茬为玉米的土壤处理中,大豆-玉米混作的根际土壤过氧化氢酶活性显著低于单作大豆和单作玉米的处理.③大豆连作和玉米连作的土壤微生物量碳、氮均高于大豆-玉米轮作.在前茬为玉米的土壤处理中,大豆-玉米混作的土壤微生物量氮显著高于单作大豆和单作玉米的处理.④土壤微生物量碳与微生物量氮及其碳氮比都与土壤过氧化氢酶活性和多酚氧化酶活性呈显著相关或极显著相关.因此,不同的种植方式能够影响大豆和玉米的根际土壤酶活性和土壤微生物量碳、氮,但变化规律不尽相同.