免耕冬小麦田土壤微生物特征和土壤酶活性对水分调控的响应

针对华北地区冬小麦的免耕农业管理方式,研究了不同水分管理方式对小麦产量及产量因子、土壤基础呼吸、土壤微生物量氮(SMBN)和土壤酶活性的影响。试验设常规灌溉(W1)、节水灌溉(W2)和无灌溉(W3)3个处理,小麦全生育期总灌水量分别为150、75和0 mm。W1与W2处理对小麦产量影响较小,但W3显著降低小麦产量。水分胁迫对冬小麦拔节期和灌浆期的土壤基础呼吸和土壤微生物量氮影响较大,土壤基础呼吸表现为W2和W3低于W1,而土壤微生物量氮的影响则表现为W1W2W3。随灌溉量的减少,土壤β-葡萄糖苷酶、多酚氧化酶和脲酶活性均有不同程度的降低。与冬小麦生长后期相比,土壤酶活性对水分的胁迫响应在生长前期更为敏感,其中0~10cm土层的土壤酶活性受水分胁迫影响大于10~20 cm土层。研究结果表明,免耕条件下灌溉方式与灌溉量显著影响了土壤微生物活性,从而调节了冬小麦产量形成。

Response of Soil Microbial Characteristics and Soil Enzyme Activity to Irrigation Method in No-till Winter Wheat Field

The purpose of this study was to understand the effects of conventional (150 mm, W1), water-saving (75 mm, W2), and zero (W3) irrigation on winter wheat yield, soil basal respiration, soil microbial biomass nitrogen (SMBN) and soil enzyme activities under no-till practice in North China Plain. Wheat yields in W1 and W2 were similar and significantly higher than that in W3. Water stress showed great influence on soil basal respiration and SMBN at jointing and filling stages, resulting in a significant decrease of soil basal respiration under W2 and W3 compared with that under W1, and a change of SMBN as W1 > W2 > W3. The activities of soil β-glucosidase, polyphenol oxidase, and urease declined with the decrease of irrigation quantity. Such influence was more sensitive in early growth period of wheat than in late growth period, particularly in the 0–10 cm soil layer. These results suggested that yield formation of winter wheat under no-till practice might result from the regualtion of soil microbial activity that received great impact of irrigation strategy.