油菜秸秆还田培肥土壤的效应及对后作水稻产量的影响

Effects of returned rapeseed straw on soil fertility and yield of subsequent rice

利用尼龙网袋定位试验,系统比较分析油菜秸秆全量还田后的腐解特征、养分释放规律、土壤养分及后作水稻的产量变化,研究油菜秸秆还田培肥土壤的效应及其对后作水稻的影响。结果表明:随还田时间的推移,秸秆腐解率逐渐增加。还田后15d,油菜秸秆的腐解率达37.2%,至还田后120d腐解率达60.9%;秸秆腐解速率呈现前期快,后期慢的特征。秸秆养分释放率与释放速率由大到小依次为钾、磷、氮,释放量由大到小依次为钾、磷、氮。秸秆还田后能显著增加土壤中碱解氮与速效钾含量,而有效磷含量与对照相比无明显变化。油菜秸秆还田对后作水稻产量及其构成的影响表现为有效穗数与每穗粒数显著增加,结实率与千粒重无明显变化,水稻产量显著提高,丰两优4号、新两优6号分别比对照增产6.4%、7.6%。油菜秸秆全量还田不仅能提高资源利用率、减少环境污染,而且能有效培肥地力,增加后作水稻产量。

In order to investigate the effects of returned rapeseed straw on soil fertility and yield of subsequent rice, the characteristic of decomposition and nutrients release of returned rapeseed straw, changes of soil fertility and subsequent rice yield were studied by method of nylon net bag. The results showed that the decomposition ratio of rapeseed straw was increased with time. About 37.2% of the straw were decomposed on 15 days after it was returned, and the decomposition ratio reached 60.9% on 120 days after it was returned. The decomposition rate of straw was quickly at the initial stage but then slowed down at the later period. The order of release ratio and release rate of the three types nutrients were K〉P〉N, while the order of nutrients release amount were K〉N〉P. The contents of available N and available K in the soil were significantly increased after straw was returned, but available P had no obvious difference between returned straw treatment and CK. There existed great effects of returned rapeseed straw on subsequent rice yield and its compo- nents. In the returned straw trement, the seed setting rate and 1 000-grain weight had no obvious difference with CK, but the the number of effective panicles and grains per pancile were significantly increased. The yield of two varieties rice Fen- gliangyou 4 and Huiliangyou 6 in returned straw trement was increased by 6.4% and 7.6 %, respectively. These results indicated that returned rapeseed straw not only improved the utilization rate of resources, reduced enviromental pollution, but also improved soil fertility and increased subsequent rice yield.