长期稻-稻-绿肥轮作对水稻产量及土壤肥力的影响

Effects of Long-Term Rice-Rice-Green Manure Cropping Rotation on Rice Yield and Soil Fertility

为探讨湘南红壤稻田多熟制增产潜力,不断提高经济效益和土壤肥力,促进农业可持续发展,从1982年开始,对红壤稻田布置了冬种紫云英(T1)、油菜(T2)、黑麦草(T3)翻压还田对水稻产量和土壤肥力影响的长期轮作制度定位试验。30年的研究结果表明:(1)与冬闲(T4)处理相比,绿肥还田能促进水稻增产,其平均增产效果和年均增产率为:T1>T2>T3,且其增产稳定性较好;(2)与T4处理相比,绿肥还田能显著增加土壤有机质含量,其中T1处理下活性有机质含量显著高于其他处理,且在有机质中所占比例最大;(3)与T4处理相比,绿肥还田能提高土壤全氮、碱解氮含量,加速土壤矿化,促进水稻对磷素和钾素吸收,其中,T1处理下土壤全氮、碱解氮含量显著高于其他处理,T2和T3处理显著高于T4处理,T1处理比T2和T3处理更能促进土壤磷素释放与吸收,致使T1处理土壤全磷累积相对缓慢,也更需要补充外界钾素;(4)稻-稻-紫云英轮作是一种较好的轮作模式。

A long-term rotation system experiment has been arranged since 1982 to maintain the soil fertility and the sustainable productivity of rice multiple cropping system in hilly red soil region in south of Hunan, continuously improving the economic benefits and promoting agricultural sustainable development. During the winter-fallow period every year, planting milk vetch （T1）, oil rapeseed （T2）, and ryegrass （T3） were conducted to study the effect of green manures on rice yield and soil fertility. The results obtained can be summarized as follows： （1） Compared with the winter-fallow treatment （T4）, the green manure treatments increased rice yield with a better yield stability. The average annual yield increase rate and effects showed a trend of T1〉T2〉 T3. （2） Compared with T4, green manure treatments increased SOM （soil organic matter） content, and among green manure treatments T1 treatment had the significantly highest soil ASOM （active soil organic matter） content and a largest proportion of soil ASOM in SOM. （3） Compared with T4, green manure treatments increased soil total N and available N contents, promoted soil mineralization and absorption of soil K and P. Soil total N and available N contents in T1 treatment were significantly higher than those in the other treatments, and those in T2 and T3 treatments were significantly higher than those in T4 treatment. The effect of promoting soil P releasing in T1 treatment was better than that in T2 and T3 treatments, leading to more slowly soil total P accumulation in T1 treatment, and more potassium application needed. （4） T1 treatment is a better rotation pattern.