【摘要】 采用尼龙网袋分解法,将一定量的黑麦草根系和地上留茬(统称黑麦草残留物)置于田间耕作层令其自然分解,分别于埋设后11,39,70,109,161和244d收集尼龙网袋内的样品,洗净,烘干,称重后用于分析全量N、P、K、Ca、Mg、Mn和Fe的含量。结果表明,黑麦草残留物在大田中通过生物降解,将养分释放到土壤中,在后作水稻的生长发育过程中,分解初期的释放量较高,埋设10d后黑麦草残留物样品中近90%的Ca和37%～50%的C、N、P、K和Fe被释放,Mn和Mg则只有0.4%～13.4%被释放。在早稻生长过程中黑麦草残留物有74.9%被分解,C、N、Mn和Mg的矿化率均在80%以下,表现出一定的缓释效应。晚稻收获时各养分的释放率达到92%～99%。理论上黑麦草根系可以为0～20cm土层贡献有机质、N、P、K、Fe、Mn、Mg和Ca分别达到865.42g/kg,26.92g/kg,1.75g/kg,23.83g/kg,2741mg/kg,75mg/kg,162mg/kg和46mg/kg。更多还原

【Abstract】 Ryegrass residue including roots and stubble collected after ryegrass cropping was put into nylon bags and buried in the cultivated layer (15-20 cm) of the paddy field soil. The decomposition rate and release rates of OM, N, P, K, Fe, Ca, Mn and Mg were determined after collection of buried samples 11, 39, 70, 109, 161 and 244 d after being buried. The results showed that the release rates of the nutrients were higher in the initial stage of decomposition. Ten days after burial, 90% of Ca, and 37%-50% of C, N, P, K and Fe had been released, but only 0.4%-13.4% of Mn and Mg had been released. During the growth of early rice, about 74.9% of residue dry matter was decomposed, and the mineralisation of C, N, P, Mn and Mg was less than 80%. When the late rice was harvested, 92%-99% of OM and the tested nutrients had been released. The release of nutrients contained in the ryegrass residue was rather slow compared to chemical fertilizers. This will be favorable for improving the nutrient utilization, preventing environmental pollution, and also for improving rice production. Theoretically, the residual ryegrass roots contributed OM, N, P, K, Fe, Mn, Mg and Ca at 0-20 cm soil depth, levels of 865.42 g/kg, 26.92 g/kg, 1.75 g/kg,23.83 g/kg,2 741 (mg/kg), 75 (mg/kg), 162 (mg/kg) and 46 (mg/kg), respectively.更多还原