陇东红豆草不同开挖期轮作冬小麦土壤养分变化的研究

CHANGES OF SOIL NUTRIENTS IN SAINFOIN-WHEAT ROTATION

陇东黄土高原半干旱区种植红豆草及不同开挖期轮作冬小麦,土壤养分变化非常显著。三年的研究结果是:(1)随时间的延续,种红豆草、冬小麦及轮作的各处理,土壤有机质增加,全氮、有效锌、水溶性钙、镁下降,全磷、钾、速效钾和铜无变化。除此外,种红豆草水解氮增加,有效磷、硼下降;种冬小麦有效铁、硼上升。(2)养分在土壤空间的变化,常量养分是表层(0～20cm)大于底层;而微量养分仅锌同外,其他相反,有效铁、硼是底层(20～50cm)的变化程度大于表层,锰的上下两层变化较小。(3)利用资源上,红豆草同化环境物质多,利用资源程度高,草粮轮作对土壤养分的亏损有一定的互补作用;另外,种红豆草的时间越长,垦后第一年轮作冬小麦的产量就越低。

There were significant changes in soil nutrient contents in the three-year sainfoin-wheat rotation experiment. The results shown that: (1)For all the treatments of pure sainfoin, pure winter wheat and sainfoin-wheat rotation, the content of soil organic matter increased while that of total N, available Zn, Ca, and Mg decreased with total P, total and available K, and available Cu keeping constant. For the pure sainfoin treatment, the amount of hydrolyzed N increased while available P and B decreased. The content of available Fe and B increased in the treatment of pure winter wheat. (2) The change in macro-nutrients is more active in topsoil (0-20cm) than in deep soil layers while the micro-nutrients varied more actively in deep soil, except the case of Zn. (3) Sainfoin can effectively utilize and convert soil nutrients. The rotation between sainfoin and wheat may be a way to maintain and improve soil fertility and needs further studies.