Effect Of Different Cultivation Patterns On Physicochemical Properties Of Soil And Rice Quality

Rice is an important food crop in China,and rice agriculture scientists have adopted various comprehensive cultivation patterns to increase production for a long time.Modern rice cultivation patterns with high input of fertilizer and water had a series of effects on resource utilization and environment while increasing rice yield.Most studies focused on yield formation,resource utilization efficiency and rice quality,but few on rice starch quality and physicochemical properties of soil is known.This study with two rice cultivars,yongyou 2640(an japonica hybrid)and wuyunjing 24(a conventional japonica inbred),were field-grown with nine cultivation patterns treatments including no nitrogen application(ON),local farmers' practice(LFP,CK),reduction of N(RN),increase in plant density and reduction of N(IDRN),precise irrigation(PI),application of rapeseed cake fertilizer(ARCF),deep plowing(DP),application of silicon and zinc fertilizer(ASZF),and application of earthworm manure(AEM).Yield and its composition,rice quality,starch quality and soil physicochemical properties were analyzed.The main results are as follows:1.Effects of different cultivation patterns on rice yieldCompared with LFP(CK),the yield of rice could be increased under the cultivation patterns of IDRN,PI,ARCF,DP and ASZF.The total spikelets,productive tillers,dry matter weight of aboveground,leaf area index and grain to leaf ratio under the above four cultivation patterns were significantly increased compared with the LFP.The main reason of increased grain yield was the total spikelet improved significantly.The results showed that optimized cultivation management pattern could improve rice population quality index and increase rice yield.2.Effects of different cultivation patterns on rice qualityCompared with the LFP,the milling quality,appearance quality,nutritional quality,relative crystallinity,solubility and expansion of starch,and RVA spectrum characteristics of starch were significantly improved under ARCF,DP and ASZF.And the enthalpy,recovery enthalpy and recovery of starch were significantly reduced by ASZF.PI and AEM significantly improved the appearance quality of rice.With the increase of nitrogen application,the nutritional quality of rice was improved,the cooking and eating quality were decreased,and the breakdown value of rice was increased and the eating quality of rice was improved by applying organic fertilizer.3.Effects of different cultivation patterns on soil physical and chemical propertiesSoil bulk density of each treatment showed an increasing trend with the advance of rice growth period.The contents of total nitrogen,total phosphorus,total potassium,alkali-hydrolyzed nitrogen,nitrate nitrogen and ammonium nitrogen and the activities of sucrase,urease and catalase were decreased with the advance of rice growth period.The content of available phosphorus and the activity of acid phosphatase increased first and then decreased,and reached peak at heading stage.The content of available potassium first decreased and then increased,and the content was the lowest at heading stage.The differences between different treatments were similar in each growth period:Compared with LFP,the ARCF,DP and ASZF treatments increased soil porosity and soil respiration intensity.The contents of total nitrogen,total phosphorus,total potassium,alkali-hydrolyzed nitrogen,nitrate nitrogen,ammonium nitrogen,available phosphorus,available potassium,and the activities of sucrose,urease,acid phosphatase and catalase in soil were significantly increased under the cultivation patterns of ARCF,DP and ASZF.PI significantly increased soil porosity,soil respiration intensity,content of alkali-hydrolyzed nitrogen,nitrate nitrogen and catalase activity at tillering stage and Panicle initiation stage,and decreased the content of ammonium nitrogen.The contents of total phosphorus,total potassium,nitrate nitrogen,available phosphorus,available potassium and urease activity in soil were significantly increased under AEM.Therefore,compared with LFP,precise irrigation,application of organic fertilizer and deep plowing could play an important role in improving the physical structure of soil and maintaining available nutrients.4.The correlation between soil physicochemical properties and yield and rice qualityThe correlation analysis showed that yield and components,rice quality and starch characteristics were closely related to soil physicochemical properties:soil porosity,soil respiration rate,total nitrogen,alkali-hydrolyzed nitrogen,nitrate nitrogen,ammonium nitrogen content in soil,sucrase,urease,catalase activity and panicle number,yield,head rice percentage,protein content,starch relative crystallinity,starch solubility and starch expansion.There was a significant or extremely significant positive correlation with amylose content and starch rebound,which indicated that the effect of improving rice yield and quality and starch characteristics could be achieved by optimizing cultivation patterns.