宁夏引黄灌区麦稻水旱轮作二熟制双免耕的土壤培肥效应

为评价麦稻水旱轮作二熟制双免耕的土壤培肥作用,采用常规测定法、比重计法、Biology-ECO法分别对参试的土壤养分、质地、微生物功能多样性等进行检测.结果表明,与传统耕作相比,连续4年冬小麦水稻全免耕轮作后,0～40 cm土壤有机质、全氮、全磷、速效氮、速效磷含量分别增加11,9％、17.1％、9.2％、26.5％、19.1％,全钾、速效钾含量分别减少0.9％、10.2％,0～20 cm土层的土壤粘粒、砂粒比例明显增加,粉粒比例明显减少.免耕冬小麦成熟期的土壤微生物功能多样性代谢活性显著高于传统耕作.0～20和20～40 cm土壤层次内反映微生物功能多样性的4种指数(Shannon-Wiener指数、Pielou均匀度指数、丰富度和Simpson优势度指数)在冬小麦整个生长季节中的变化趋于一致,即在分蘖期和拔节期传统耕作高于连续4年免耕处理,在灌浆期和成熟期连续4年免耕处理高于传统耕作处理.连续4年免耕0～40 cm土壤肥力明显优于连续3年双免耕的肥力.免耕对提高土壤肥力,尤其是对促进冬小麦中、后期生长有利.

Effect on Soil Fertility in Paddy Rice upland Wheat Rotation Double Cropping System with Double zero tillage in Yellow River Ningxia Basin

To evaluate the effect on soil fertility in paddy rice upland wheat rotation double cropping system with double zero tillage, Conventional soil testing method, Biology ECO and Densitometer methods were used to investigate the contents of nutrients in soil, siol structure and activities and diversity of soil microorganism. The results showed that, compared with traditional farming system (CK), the contents of soil organic matter, total nitrogen, total phosphorus, available nitrogen and available phosphorus increased by 11.9%, 17.1%, 9.2%, 26.5% and 19.1%, respectively, within 0~40 cm depth soil layer after four year double zero tillage cropping in succession with winter wheat rice rotation system. Meanwhile, total potassium and available potassium decreased by 0.9% and 10.2%, respectively. Within soil layer of 0~20 cm, the proportions both clay soil and sand particles increased but proportions of silt particles decreased in the double zero tillage cropping system, compared with CK. The metabolic diversity of functional microorganism in the soil and its biological activity were significantly greater than that under traditional farming system. The changes based on Shannon Wiener, Pielou, Richness and Simpson measurements of metabolism diversity of functional microorganism were consistent across soil layers 0~20 cm and 20~40 cm with that in the whole wheat growth season.The indices were higher at tillering and jointing stages of winter wheat for traditional farming treatment, whereas they were higher at grain filling and maturing stages for the four year double zero tillage cropping treatment. The results also showed that the soil fertility of four year double zero tillage cropping was distinguishably better than that of three year double zero tillage cropping. In conclusion, four year double zero tillage cropping benefited soil fertility, especially at the middle and late growth stages of winter wheat.