Interactive Effects Of Liming And Straw Retention On Grain Yield And Soil Properties In A Double Rice Cropping System

Growing studies have shown that soil property is declining and grain yield is stagnating and even shows a downward trend under long-term intensive cultivation.In addition,the acidification of paddy soils is becoming an important factor limiting crop yield in south China.Rice straw application is essential to improve soil fertility and crop yield.But it has a limited capability to neutralize soil acidity.However,the effect of lime application is an effective measure to alleviate paddy soil acidification.Therefore,the objective of this study was to examine the interactive effect of liming and straw retention on yield and soil properties in a double rice cropping system.A two-year experiment was conducted with a completely randomized block design with two factors of lime addition(L)straw retention(RS).Inbred rice variety ‘Zhongjiazao17' and hybrid rice variety‘Wuyou308' was used as early rice and late rice cultivars,respectively.The main results are as follows:Results showed that both liming and straw retention could significantly enhance grain yield in both early-and late-rice growing season.There was interactive effect of liming and straw retention on late-rice yield in both years.Compared with CK in 2015,each treatment increased the rice yield from 2.84% to 13.27% in the early rice.L and L+RS increased rice yield by 21.19% and 31.07%,But RS reduced rice yield by 0.85%in the late rice.In 2016,each treatment increased the rice yield from 9.60% to 35.03%.L,L+RS and RS increased rice yield by 21.94%,32.17% and 1.21% with the control in the late rice.L significantly increased the number of panicles in the double rice yield.RS significantly increased the number of panicles in the early rice,but had no significant effect in late rice.And that significant interaction was found in the late rice.Compared with CK in 2015,each treatment increased the number of panicles from 2.38% to 11.90% in the early rice.L and L+RS increased the number of panicles by 5.30% and 19.79%.However,RS reduced the number of panicles by 5.65% in the late rice.In 2016,each treatment increased the number of panicles from 5.34% to 20.28% in the early rice.L and L+RS increased the number of panicles by 4.95% and 14.49%,However,RS reduced the number of panicles by 4.59% in the late rice.The rice yield was positively correlated with the number of panicles in the double rice yield(P ? 0.01).L significantly increased the N uptake of the double rice at maturity stage,and significantly increased the P uptake in the late rice.But it had no significant effect on K uptake in the double rice yield.RS significantly increased the nutrient uptake of the double rice at maturity stage.Liming and straw retention synergistically increased the N uptake in the late rice yield.L significantly increased soil p H and the available nitrogen at before midterm.But itreduced the concentration of available phosphorous.RS significantly increased available nitrogen except the stage of tillering in the late rice yield.And it significantly increased the concentration of available phosphorous and potassium in the double rice yield.Liming and straw retention synergistically increased theavailable nitrogen at tillering in the late rice yield,and synergistically increased the available phosphorous at tillering,heading and maturity stageboth early and late rice yield in 2015.L significantly enhanced soil p H,the concentration of soil organic carbon,available nitrogen,CEC,Exchangeable K+,Exchangeable Ca2+,and promoted the activity of soilureases,invertases,celluloses and proteinases.But it significantly reduced the concentration of available phosphorous,Exchangeable acidity,Exchangeable H+,Exchangeable Al3+after the 2-year experiment.RS significantly enhancedthe concentration of soilavailable nitrogen,phosphorous and potassium,organic carbon,CEC,Exchangeable K+,Exchangeable Mg2+,and promoted the activity of soil ureases,invertases,celluloses,proteinases and acid phosphatases.But significantly reduced soil bulk density,CWHC,LWHC and the concentration of Exchangeable Al3+.And no significant interaction was foundafter the 2-year experiment.