Effects of green manure on rice yield and soil fertility in China:a Meta-analysis
This study provided scientific basis for exploring the effects of planting green fertilizer on rice yield and soil fertility,and for increasing and stabilizing rice yield and soil improvement.Data were collected from the published literature and 362 databases of rice yield and soil fertility under green manure(GM)and winter fallow field(FFP)treatments were established.A Meta-analysis method was used to quantify the increase of green fertilizer on rice yield and soil fertility in different regions,rice cropping patterns,soil properties,nitrogen fertilizer dosage,and green fertilizer types,and to explore the main controlling factors affecting green fertilizer effects by using random forest model.The results showed that GM treatment had the largest effect on soil organic matter content in southern rice region(21.17%).Under different cropping modes,the increase of GM treatment on rice yield and soil fertility was both ranked as double cropping rice＞single cropping rice.When soil total nitrogen content was less than or equal 1.5 g/kg and soil organic matter content was less than or equal 20 g/kg,the yield increased significantly.When the nitrogen application rate of GM treatment was less than or equal 150 kg/hm2,the yield and soil organic matter content were both increased by 12.47%and 22.36%,respectively.However,the increase rate of GM was decreased with the gradual increase of nitrogen application rate.Under different green fertilizer varieties,the increase of GM on yield and soil organic matter content was different.In terms of yield increase,it ranked as leguminous green fertilizer(12.47%)＞non-leguminous green fertilizer(7.22%)＞mixed green fertilizer(6.32%);In terms of soil organic matter content improvement,it ranked as mixed green fertilizer(12.69%)＞non-legume green fertilizer(10.93%)＞legume green fertilizer(9.37%).The results of random forest analysis showed that the main controlling factors of GM treatment on rice yield were soil organic matter,nitrogen application and available phosphorus contents(contribution rate of 18%,16%and 15%,respectively),while the main influencing factors of GM on organic matter were region,available potassium and available nitrogen contents(contribution rate of 14%,12%and 11%,respectively).Therefore,planting green fertilizer could significantly improve rice yield and soil fertility,especially under the condition of low fertility soil,GM treatment had a good increase in yield.The combination of GM and chemical fertilizer could promote rice yield increase and soil organic matter content in paddy field,but the nitrogen application of GM treatment should not exceed 150 kg/hm2.Legume green fertilizer was recommended for rice and green fertilizer rotation in the rice area of Yangtze River Basin.And in the southern rice area,mixed green manure was recommended.
green fertilizerriceyieldsoil fertilityintegration analysisrandom forest
NETL
NSTL
万方数据
