整合分析秸秆还田对中国主要粮食作物氮肥利用率的影响

Effects of straw returning on nitrogen use efficiency of major grain crops in China:a meta-analysis

秸秆还田是提高作物氮肥利用率的有效途径之一。但由于作物的氮肥利用率受到环境条件和管理方式的影响,且多数研究只在某一特定区域或条件下进行,对于全国不同区域秸秆还田对氮肥利用率影响的研究缺乏系统分析和比较。为了探明我国农田主要粮食作物氮肥利用率对秸秆还田的响应及其关键调控因素,基于77份文献的数据,开展了整合分析(Meta-analysis)。结果表明,与秸秆不还田相比,秸秆还田条件下NUE(氮肥利用率)和PFPN(氮肥偏生产力)的效应值分别显著增加10.0%和6.14%(P<0.05)。秸秆还田方式是影响NUE效应的关键调控因子,覆盖还田NUE提升幅度是翻压还田提升幅度的2倍左右。土壤全氮、土壤酸碱性及气候类型是秸秆还田调控PFPN的关键因子。当土壤全氮含量>1.25 g·kg^(-1)或在中性土壤条件下时,PFPN提升幅度显著高于该因子的其他水平。在亚热带季风气候和温带季风气候条件下,秸秆还田对PFPN提升效果显著。回归分析发现,秸秆还田对PFPN的影响因土壤全氮含量上升而提高(P<0.05);随土壤pH的增加而先上升后下降;年均温和降雨量与PFPN之间均呈非线性相关关系(P<0.0001)。秸秆还田可以显著提高我国主要粮食作物的氮肥利用率,但不同表征指标对于秸秆还田的响应程度及其关键调控因素存在显著差异。

Straw returning is one of the important approaches in improving the nitrogen efficiency of crops.Nitrogen efficiency is affected by environment conditions and field management.However,most studies were conducted in specific region or environment,systematic comparison and analysis of straw returning on nitrogen use efficiency in different regions of China was less.This study conducted a meta-analysis based on data from 77 peer-reviewed publications to determine the response of nitrogen use efficiency of major grain crops in Chinese farmland to straw return and its key regulatory factors.The results showed that compared to non-straw return,the straw return increased the effect size of NUE(nitrogen fertilizer use efficiency)and PFPN(nitrogen partial factor productivity)by 10.0%and 6.14%(P<0.05).The returning method was the key regulatory factor for the effect of straw returning on NUE,in which the increase of NUE in mulching returning was about 2 times than that in burying returning.The key factors affecting the regulation of PFPN by straw returning were soil total nitrogen,soil acid-base and climate type.When soil total nitrogen content was more than 1.25 g·kg^(−1) or under neutral soil conditions,the increase of PFPN was significantly higher than other levels with this factor.Under subtropical monsoon climate and temperate monsoon climate,straw returning had significant effect on PFPN enhancement.Regression analysis showed that the effect of straw returning on PFPN increased with the increase of soil total nitrogen content(P<0.05),and increased first and then decreased with the increase of soil pH.The average annual temperatures and rainfall were found to be nonlinear correlated with PFPN(P<0.0001).In conclusion,straw returning would significantly increase the nitrogen fertilizer utilization rate of major grain crops in China,while there were significant differences in the response degree of different indexes to straw returning and its key regulatory factors.