秸秆还田对麦-玉轮作中土壤肥力及生物学性状的影响

Effects of Returned-Straw on Soil Fertility and Soil Biological Traits in Wheat-Maize Rotation Systems

摘要: 为探明秸秆还田对麦-玉轮作中土壤肥力及生物学性状的影响，利用田间长期定位试验，研究了不同秸秆还田量条件下的作物产量、土壤有机质、速效养分、微生物数量及土壤酶活性。研究表明，秸秆还田能增加小麦(两季)、玉米(两季)产量，增幅分别为5.3%~25.0%、15.8%~26.1%。秸秆还田后，土壤有机质含量，50%、100%和150%秸秆还田条件下，增幅分别为0.2~0.4 g/kg，土壤碱解氮、有效磷、速效钾含量增加6.64~9.00 mg/kg、3.37~4.07 mg/kg、10.33~19.00 mg/kg，细菌、真菌、放线菌增幅分别为2.2 × 10⁸~3.1 × 10⁸、0.5 × 10⁶~3.5 × 10⁶、1.3 × 10⁷~1.9 × 10⁷个/g，土壤脱氢酶、脲酶、酸性磷酸酶活性分别增加3.82%~12.98%、36.0%~80.0%、12.99%~37.80%。但秸秆还田量达到150%时，在土壤肥力及生物学指标方面出现转折点，建议不超过100%秸秆还田为宜。

Abstract: In order to test effects of returned-straw on soil fertility and soil biological traits in wheat-maize rotation systems, we investigated the soil organic matter, soil nutrient capacity, soil microorganism and soil enzyme activity. The results showed that returned-straw increased wheat yield (2 seasons) and maize yield (2 seasons) by 5.3% - 25.0% and 15.8% - 26.1% respectively, increased the soil organic matter by 0.2 - 0.4 g/kg under the condition of 50%, 100%, 150%, increased available nitrogen by 6.64 - 9.00 mg/kg, increased available phosphorus by 3.37 - 4.07 mg/kg, increased available potassium by 10.33 - 19.00 mg/kg, increased the amount of soil bacteria, fungi and actinomycetes respectively by 2.2 × 10⁸ - 3.1 × 10⁸/g, 0.5 × 10⁶ - 3.5 × 10⁶/g, 1.3 × 10⁷ - 1.9 × 10⁷/g, and increased the activity of soil dehydrogenase, soil urease, soil acid phosphatase respectively by 3.82% - 12.98%, 36.0% - 80.0%, 12.99% - 37.80%. But excessive amount of straw returned 150% was not beneficial from farmland productivity because of its negative turning point in soil fertility and soil biological traits. We suggested the amount of returned-straw was not more than 100%.