油菜与小麦秸秆浸出液对水稻种子萌发及幼苗生长的影响

为了解油菜-水稻与小麦-水稻两种轮作体系中水稻生长的差异，分析油菜作为良好茬口的原因，以秸秆 在土壤中腐解的溶液为材料，研究多熟种植体系对后作水稻的增产趋势。采用多因素随机区组设计，包括秸秆类 型、添加液类型和秸秆浓度三种因素，其中秸秆类型为油菜、小麦秸秆，添加液类型为蒸馏水和营养液，秸秆浓度分 别为空白对照（0 g/L）、低浓度（1 g/L）、中浓度（5 g/L）和高浓度（20 g/L），对应田间秸秆还田量0 kg/hm2、1500 kg/hm2、 7500 kg/hm2和30 000 kg/hm2。结果表明，秸秆类型、添加液类型及浓度对水稻发芽无显著影响，而对水稻幼苗生长 具有显著改变。秸秆浓度为1和5 g/L时，蒸馏水作为添加液条件下，油菜秸秆处理的水稻幼苗干重较小麦秸秆处 理显著提高10.7%~44.4%；以营养液作为添加液时，油菜秸秆处理的水稻幼苗干重比小麦秸秆处理高2.2%~12.1%。 与蒸馏水作为添加液相比，营养液处理的稻苗干重极显著增加，增幅达53.7%~130.0%。不同秸秆浓度培养液间以 5 g/L时水稻幼苗干重和株高达到最大。蒸馏水作为添加液时，水稻幼苗养分积累量与干重表现出一致的趋势，其 中氮积累量间的差异最为显著；而以营养液作为添加液时，仅在播种后第12 d，5 g/L秸秆浓度培养液处理的水稻幼 苗氮、钾积累量表现出显著差异。与蒸馏水作为添加液相比，营养液处理的稻苗氮、磷、钾养分累积量增加了2.0~ 3.0倍、1.0~2.0倍和1.4~1.7倍。水稻幼苗氮、钾积累量均以秸秆浓度为5 g/L时最高，磷累积量差异不大。与营养液 相比，蒸馏水作为添加液时，油菜与小麦秸秆浸出液敏感指数差异更大。油菜和小麦两种秸秆，它们的浸出液均能 促进水稻幼苗生长，油菜秸秆浸出液对水稻幼苗生长的促进效果显著强于小麦。

Effects of rapeseed and wheat straw residue leachates on germination and growth of rice seedlings

To reveal the reason of rice yield promotion by rapeseed straw under multi-crop planting systems,rapeseed-rice and wheat-rice rotation systems were investigated by simulative straw residue leachates effect on rice growth. The leachates from straw in soil were used as materials under a randomized block design with 3 factors,which included straw types, additive liquid types and leachate concentration. Straw type contains rapeseed and wheat. Additive liquid types are distilled water and nutrient solution. Straw concentration includes control(0 g/L),low(1 g/L), medium(5 g/L)and high(20 g/L), corresponding to the amount of straw incorporation of 0 kg/hm², 1500 kg/hm², 7500 kg/hm² and 30 000 kg/hm². Results showed that straw type, additive liquid type and concentration had no significant impact on seed germination, but had significant influence on growth of rice seedlings. Dry weight of rice seedlings for rapeseed straw residue leachate was significantly 10.7-44.4% higher than that of wheat straw in distilled water. Dry weight of rice seedlings with rapeseed straw residue leachate was 2.2-12.1% higher than that of wheat straw in nutrient solution at 1 and 5 g/L straw. Compared with distilled water, dry weight of rice seedlings increased by 53.7-130.0% treated by nutrient solution. The dry weight and plant height of rice seedlings reached the maximum at 5 g/L among different straw concentrations. Nutrient accumulation of rice seedlings showed a similar trend with dry weight. The difference between nitrogen accumulation was the most significant with distilled water as additive liquid. Only on the 12 th day after sowing, the nitrogen and potassium accumulation of rice seedlings at 5 g/L straw concentration showed significant differences in nutrient solution. Compared with distilled water, N, P, K accumulation of rice seedlings treated with nutrient solution increased by 2.0-3.0 times, 1.0-2.0 times and 1.4-1.7 times. The accumulation of nitrogen and potassium in rice seedlings was the highest at 5 g/L straw concentration,with no difference in phosphorus. Compared with nutrient solution, the difference in sensitivity index between rapeseed and wheat straw residue leachate was greater than those with distilled water as additive liquid. In conclusion,both rapeseed and wheat straw residue leachates could promote rice growth. Comparing with wheat straw, rapeseed straw residue leachate promoted rice growth better.