稻麦两熟系统产量对秸秆还田的响应:基于Meta分析

Variation in yield response to straw incorporation in rice-wheat rotation system: Meta-analysis

[目的]本文旨在明确稻麦两熟系统秸秆还田对作物产量的影响。[方法]以稻麦两熟系统为研究对象,通过搜集、整理近20年的文献数据,使用Meta分析方法,定量研究了长江流域稻麦产量对秸秆还田的响应变异及其影响因素。[结果]秸秆还田能够显著增加稻麦产量,但是,水稻产量的响应程度要显著强于小麦。秸秆不同还田量对小麦产量的影响不明显,但小麦秸秆还田量大于3 750 kg·hm^(-2)时显著增加水稻产量。在长江下游地区,水稻秸秆还田显著降低小麦产量,而在长江中、上游地区,水稻秸秆还田显著增加小麦产量。在长江流域,小麦秸秆还田均显著增加水稻产量。基肥N肥以尿素形态施用下水稻秸秆还田可以增加小麦产量,但以复合肥形态施用下小麦产量对水稻秸秆还田的响应不显著。在稻秸还田条件下,全生育期N肥用量大于200 kg·hm^(-2)时,小麦产量显著降低;N肥用量不超过200 kg·hm^(-2)时,小麦产量显著增加。全生育期P肥最适用量为40~60 kg·hm^(-2),在此条件下,秸秆还田均能显著增加稻麦产量。土壤有机质含量为20~30 g·kg^(-1)时,秸秆还田能够显著提高稻麦产量;但是土壤有机质含量过高(如大于30 g·kg^(-1))时,水稻秸秆还田却降低了小麦产量。旋耕显著降低了稻秸还田下小麦产量,但其他耕作方式却能够显著增加秸秆还田对稻麦产量的正效应。此外,麦秸还田下,水稻产量在不同栽培方式间也存在差异。[结论]秸秆还田能够增加稻麦产量,但还田效益需要综合考虑区域资源特点、土壤本底条件、耕作栽培及水肥管理等因素。

[ Objectives ] In order to reconcile the debate about the effects of straw incorporation, this study aims to investigate the effects of straw incorporation on crop yields in the rice-wheat rotation systems, and provide theoretical support for the extension of straw return method. [ Methods ] We utilized flee-wheat rotation system in the Yangtze River basin as our model system, collected the data from 122 trials in 27 publications and conducted Meta-analysis to investigate the response of crop yield to straw incorporation, as well as the potential factors which might affect the response pattern, including straw return amount, N type as basal fertilizer, N, P, K fertilizer amount, soil type, tillage and cultivation methods and climate, etc. [ Results] Both the yield of wheat and rice was positively increased by straw return. But rice yield showed a bigger magnitude than wheat yield. Multiple factors affected the yield of rice and wheat to straw incorporation. Wheat yield was not affected by different rice straw amounts, but rice yield significantly increased when the wheat straw amount was more than 3 750 kg＂ hm-2. In the lower Yangtze River basin, rice straw incorporation significantly reduced wheat yield, while it increased at the median and upper Yangtze River basin agricultural regions. Urea as basal N fertilizer will increase but compound fertilizer as basal N fertilizer did not affect the response of wheat yield to rice straw return. Under rice straw incorporation, wheat yield was significantly reduced when N fertilizer amount was greater than 200 kg. hm-2 ;however, it significantly increased when N amount was less than or equal to 200 kg＂ hm-2. The optimmn P amount was 40-60 kg-hm-2, under which conditions, straw incorpora- tion significantly increased both rice and wheat yields. The K fertilizer amount did not affect the effects of straw return on both crop yields. Wheat straw return significantly reduced rice yield in the fluvo-aquic soils. The soil organic matter （SOM） content of 20- 30 g.kg-l will promote the positive effects of straw return on both crop yields. However,when the SOM content was high,i.e. ,greater than 30 g ~ kg-1, rice straw return reduced wheat yield. Other soil attributes, including total nitrogen, available phosphorus, available potassium and pH, did not affect the straw return effects. Rotary tillage reduced wheat yield under rice straw incorporated;however, other tillage methods positively affected the straw return effects on both crop yields. Compared with seedling broadcasting and direct-seeding, manually transplanting significantly increased the positive response of rice yield to wheat straw return. In summary, rice yield was significantly increased by wheat straw return, while wheat yield was not affected by rice straw incorporation. [ Conclusions ] The response of rice and wheat yield to straw return is a complicated process, which is determined by straw return amount, climate, tillage and cultivation method, fertilization regime and soil attributes.