冬季种养结合对双季稻生长与土壤肥力的影响

【目的】以长江中下游地区冬季休闲稻田为研究对象,研究冬季种养制度对后季稻田土壤肥力及水稻产量的影响,以期为南方稻田生态保育提供理论依据。【方法】设置紫云英养鸡(milk vetch+ chicken, MC)、黑麦草养鸡(ryegrass + chicken, RC)、单种紫云英(milk vetch, M)、单种黑麦草(ryegrass, R)及冬闲(winter fallow, WF) 5个处理。【结果】冬季种养期间,MC和RC两处理水稻产量均显著高于其他处理,且MC处理增产效果最佳。MC和RC两处理能显著提高双季稻田有机质、全氮、铵态氮和硝态氮含量,与冬闲相比分别提高了17.36%和22.95%、73.73%和250.48%、76.36%和85.11%、67.89%和70.05%;土壤全磷和速效磷含量以M处理最高;各处理对全钾含量影响不大。相关分析表明,水稻理论产量与成熟期土壤硝态氮、铵态氮、全氮、有机质含量显著相关(P<0.05),冬季种养主要通过提高有效穗数影响水稻产量。【结论】与冬闲和单种绿肥相比,绿肥过腹还田有利于土壤有机质、全氮、铵态氮、硝态氮含量的提高;与单种绿肥相比,绿肥过腹还田更有利于水稻分蘖数、叶面积系数和干物质量与稻谷产量的形成,且紫云英养鸡处理效果最显著。冬季种养结合模式下,有机质、全氮、铵态氮、硝态氮利于增源扩库,促进水稻增产。因此,冬闲田种养结合可满足后季水稻生长的养分需求,在稻田生态保育的基础上促进水稻增产,对长江中下游地区稻田可持续发展具有极其重要的指导意义。

Effects of Rice Planting Combined with Chicken Raising in Winter on Double-cropping Rice Growth and Soil Fertility

【Objective】The research aims to illuminate the effects of rice planting coupled with chicken grazing in winter on soil fertility and rice grain yield in the middle and lower reaches of the Yangtze River.【Method】Five treatments were designed, including milk vetch + chicken(MC), ryegrass + chicken(RC), milk vetch(M), ryegrass(R), winter fallow(WF).【Result】Yields in MC and RC were significantly higher than those of other treatments. Rice yield in MC was the highest. The content of organic matter, total nitrogen, ammonium nitrogen and nitrate nitrogen in double-cropping rice fields under MC and RC were significantly increased by 17.36% －22.95%, 73.73% －250.48%, 76.36% －85.11% and 67.89% －70.05%, respectively. However, the total phosphorus and available phosphorus contents under M were the highest, and every treatment had little effect on the total potassium content. Correlation analysis showed that there were significant correlations between theoretical yield of rice and soil nitrate nitrogen, ammonium nitrogen, total nitrogen or organic matter contents (P < 0.05).【Conclusion】Compared with green manures or winter fallow, chicken manure returning was more effective in improving the contents of soil organic matter, total nitrogen, ammonium nitrogen and nitrate nitrogen, which helps increase the rice tiller numbers, leaf area coefficient, dry matter and yields, and the changes under milk vetch + chicken was the most significant. Under the mode of rice planting combined with chicken raising in winter, soil organic matter, total nitrogen, ammonium nitrogen and nitrate nitrogen contents improved rice grain yield. Therefore, combining rice planting and chicken raising in winter meets the nutrient demand of rice growth in the following season. Thus, rice yield increase based on ecological field conservation plays an important role in sustainable development of rice production in the middle and lower reaches of the Yangtze River.