Experimental Study On Water And Nitrogen Management Model In Rice Field Under The Condition Of Zeolite

Rice is one of the main food crops in China,whose stable production and safe supply play prominent roles in national food security and social stability.However,water shortage,serious environmental pollution,and low water and nitrogen utilization have been increasingly highlighted in actual production and gradually become main factors limiting the sustainable development of rice,natural zeolite with the abilities of retaining water and fertilizer was introduced into the production system.Firstly,a split-plot design with four nitrogen application rates,two zeolite application rates,and three replications was conducted in conventional flooding irrigation.The main plots were four nitrogen application rates including 0 kg·ha-1,70 kg·ha-1,140 kg·ha-1 and 210 kg·ha-1,which were respectively represented by No,N1,N2 and N3.The sub-plots were zeolite application at two levels(Z0,0 t-ha-1;Z1,10 t·ha-1).The experiment studied the effects of different nitrogen and zeolite application rates on growth traits,photosynthetic characteristics,dry matter and nitrogen accumulation,grain yield and nitrogen utilization efficiency,and then determined appropriate nitrogen management measures.Based on the field nitrogen and zeolite experiment,another split-plot experimental design with the irrigation regimes as main plots(WCF,conventional flooding irrigation;WAWD,alternate wetting and drying irrigation)and zeolite application rates and particle sizes as sub-plots(Z0,0 t·ha-1;Zso,10 t·ha-1 of 80-mesh zeolite;Z10,10 t·ha-1 of 10-mesh zeolite)was carried out in a pot experiment.This water and zeolite experiment analyzed the effects of different irrigation regimes and zeolite application rates and particle sizes on rice growth,physiological characteristics,grain yield and water use efficiency.Finally,this research confirmed high yield and efficiency water-nitrogen management measures to provide theoretical foundation for the green and efficient production of rice.The main results are presented as follows:(1)Applying with zeolite application rate of 10 t·ha-1 significantly increased soil cation exchange capacity(CEC)and promoted available nitrogen supply for rice growth in conventional flooding paddy,in which CEC,NH4+-N and NO3--N increased by 12.5%,16.2%,and 36.4%,respectively.(2)The addition of nitrogen and zeolite significantly increased leaf area index,leaf SPAD value,and further promoted photosynthetic rate to accumulate dry matter and nitrogen and form yield.In the main effect of nitrogen and zeolite,all the indexes observed reached the maximum value in the N3 and Z1 treatment.When N3 was combined with Z1,rice yield reached a maximum of 10.25 t·ha-1.Compared with the traditional farmer management(N3Z0),N3Z1 increased yield by 4.6%and apparent nitrogen use efficiency 24.3%.(3)Compared with conventional flooding irrigation,light dry and wet alternative irrigation reduced water consumption by 9.7%at the whole growth stage,and did not significantly affect growth traits,dry matter accumulation,nitrogen accumulation or the formation of final yield,thus improve water use efficiency by 9.5%.(4)Compared with zeolite-free treatment,the use of 10 t·ha-1 80-mesh and 10-mesh zeolite significantly increased soil CEC and available nitrogen content,promoted the increase of tillering number,leaf area index and SPAD value,and significantly enhanced the photosynthetic rate,dry matter production,nitrogen accumulation,and grain yield formation.The use of 10 t·ha-1 80-mesh and 10-mesh zeolite increased yield by 6.3%and 5.9%,water use efficiency by 7.8%and 6.0%without any influence on water consumption,respectively.The treatments of alternative dry and wet irrigation combined with 10 t·ha-1 zeolite(WAWDZ80 and WAWDZ10)more obviously improved water use efficiency relative to conventional irrigation without zeolite(WCFZ0),which were 18.0%and 16.2%,respectively.The particle sizes of 80-mesh and 10-mesh zeolite had no influence on the indexes observed.Consequently,this study recommended that the appropriate water and nitrogen management measures for rice in the region were 210 kg·ha-1 nitrogen fertilizer and 10 t·ha-1 80-mesh or 10-mesh zeolite under light dry and wet alternative irrigation.This measure could improve the utilization efficiency of water and nitrogen on the basis of stable yield and achieve the goals of efficient rice production and sustainable development.