Effects of different mulching models and nitrogen fertilization on_ the quantity of soil microorganisms during the fallow period of winter wheat | 覆盖模式及施氮量对小麦休闲期土壤微生物数量的影响

Chinese. 探讨在冬小麦生长季进行的不同覆盖模式和施氮处理，是否在休闲期间仍对土壤微生物的活动有显著影响，为土壤施肥及栽培模式技术的完善提供参考。在小麦收获后夏季休闲季节，采集不同覆盖栽培（常规不覆盖、秸秆覆盖、平地覆膜）和不同施氮量（N0（不施N）、N120（施N 120 kg/hm2）、N240（施N 240 kg/hm2））处理小区中小麦残留根系的根区、根外土壤样品，测定并分析土壤微生物数量的变化。①在冬小麦生长季进行的秸秆覆盖及平地覆膜处理，可不同程度地增加休闲期间小麦残留根系根区、根外土壤固氮菌和硅酸盐细菌的数量。根区固氮菌平均数量（×105 CFU/g）表现为覆草（17.18）覆膜（12.90）常规（6.58）；覆膜栽培处理下，根区、根外土壤硅酸盐细菌平均数量（×104 CFU/g）最高，分别为常规栽培的3.43和4.64倍。②不同覆盖模式下，休闲期间根区土壤细菌数量、根区和根外土壤的放线菌、真菌和硅酸盐细菌数量均在施氮量为N240时最多，但根区、根外固氮菌数量则在施氮量为N240时最少。③小麦残留根系根区土壤微生物数量，尤其是放线菌及硅酸盐细菌数量均明显高于根外土壤。于冬小麦生长季进行覆膜及覆草栽培，能分别增加休闲期小麦残留根系根区土壤中的细菌、硅酸盐细菌和真菌、固氮菌数量，改变休闲地土壤中的微生物组成，有利于土壤肥力的恢复。施氮量的增加可调节小麦收获后残留根系周围的C/N比，有利于残留根系的分解，从而能明显增加休闲期间某些土壤微生物种群的数量。

English. The effects of mulching measures and nitrogen fertilization during the growth stage on the quantity of soil microorganisms during the fallow period were conducted. The rootzoon and bulk Soil samples were collected on the 52nd day after the wheat harvest from the plots of different treatments under 3 mulching models (conventional, plastic film mulching, straw mulching) and 3 nitrogen fertilization rates (N0, N120, N240), and the quantity of different microflora were analyzed.① In comparison with the conventional cultivation model, the plastic film mulching and straw mulching models significantly increased soil nitrogen-fixing bacteria and silicate bacteria in winter wheat fallow field. The average quantity(×105 CFU/g) of rootzone soil nitrogen-fixing bacteria was straw mulching（17.18） plastic film mulching（12.90）conventional（6.58）; The rootzoon and bulk Soil silicate bacteria under straw mulching cultivation model were 3.43 and 4.64 times higher than that in the conventional cultivation model. ② Contrary to the rootzoot and bulk soil nitrogen-fixing bacteria,when the application of N fertilizer was N240, the rootzoon and bulk soil actinomycetes, fungi, silicate bacteria, the rootzoon siol bacteria under different mulching models were the highest. ③ The wheat residual roots microorganisms (especially for soil actinomycetes and silicate bacteria) were remarkably more than that of bulk soil. Compared with the conventional cultivation model, the plastic film mulching and straw mulching during the growth stage of the winter wheat can increase the quantity of the rootzoon and bulk soil bacteria, fungi, nitrogen-fixing bacteria and silicate bacteria during the fallow period, change the ratio of soil microorganisms, and it’s beneficial to restore the soil fertility. The increase of nitrogen fertilization can change the soil C/N ratio of the wheat residual roots, and it’s beneficial to the decomposition of the residual roots, and affects the quantity of soil microorganisms.