Effect Of Tea Cultivar On Change Of Nutrient Contents In Soil Aggregates

Tea（Camellia sinensis）is perennial woody plants.long-term tea planting will lead to changes in soil nutrient content which can impact tea plantations.different size of soil aggregates can affects soil nutrient content and availability.Studying on the changes of nutrient with in soil aggregates in the different tea cultivars has a role of significant instruction to fertilization management of tea plantations.In this research,the cultivars of tea of fudingdabai,chuanmu No 217,chuancha No 3,chuannonghuangyazao are the research object to have determineation and analysis on effect of content and contribution rates of tea cultivars on change of nitrogen,phosphorus,potassium and exchange base cation in non-water stable aggregates,water stable aggregates and micro aggregates.The result showed nutrient content responded to different tea cultivars,and provide evidence for scientific management of soils in the Tea plantation.The research result indicate:（1）The contents of soil total N and available P mainly distributed in<0.25 mm non-water stable soil aggregates,with 0.65-1.23 g kg^-1and 8.6-86.7 mg kg^-1,respectively.Available N are increased fist and then decreased of particle size of aggregates,and higher values which are 45-121 mg kg^-1.Total P,Total K,exchangeable Ca,exchangeable Mg are relatively even in soil aggregates of all particle sizes,with 0.53 g kg^-1-1.15 g kg^-1、10.1 g kg^-1-13.5 g kg^-1、1.25 cmol kg^-1-2.14cmol kg^-1、0.24 cmol kg^-1-0.41 cmol kg^-1,respectively.The contents of soil Total N,available N,Total P,exchangeable Ca,exchangeable Mg in chuancha No 3 soil were lower than other cultivars.However,the exchangeable Na and available P contend higher than other cultivars.And the contents of soil available K and exchangeable K in chuannonghuangyazao soil were higher than those in other cultivars.The contribution rates of non-water stable soil aggregates to soil nutrient showed that the dominant size fraction was>5 mm particle sizes with values55.35%-77.56%。The contribution rates of>5 mm in fudingdabai soil were higher than those in other cultivars and<0.25 mm in fudingdabai soil were higher than those in other cultivars.（2）The contents of soil total N mainly distributed in > 5 mm water stable soil aggregates,with 1.01g kg^-1-0.58g kg^-1.The contents of soil available N,available P are increased with decreased of particle sizes of soil water stable aggregates,and higher values(31 mg kg^-1-111 mg kg^-1、8.6 mg kg^-1-68.3 mg kg^-1)are found in<0.25mm;Total P,Total K,exchangeable Ca,exchangeable Mg are relatively even in soil aggregates of all particle sizes.The contents of soil Total N,available N,Total P,exchangeable Ca,exchangeable Mg in chuancha No 3 soil were lower than other cultivars.However,the exchangeable Na contend higher than other cultivars.And the contents of soil Total P,available K and exchangeable K in chuannonghuangyazao soil were higher than those in other cultivars.The highest contribution rates of water-stable aggregates to soil nutrient were in size>5 mm and<0.25 mm,with20.95%-42.82%、10.70%-25.68%,respectively.The contribution rates of>5 mm in chuancha No 3、chuannonghuangyazao soil were higher than those in other cultivars and<0.25 mm in chuancha No 3、chuannonghuangyazao soil were higher than those in other cultivars.（3）The contents of soil total N,total P are decreased fist and then increased of particle size of micro aggregates,and higher values(1.30 g kg^-1-1.79 g kg^-1、0.92 g kg^-1-1.46 g kg^-1)are found in<1μm particle size The contents of soil available N,available,P available K,exchangeable K,exchangeable Ca mainly distributed in<1μm micro aggregates,with 67 mg·kg^-1-118 mg kg^-1、14.0 mg kg^-1-77.8 mg kg^-1、100.5mg kg^-1-292.2 mg kg^-1、0.16 cmol·kg^-1-0.47 cmol kg^-1、1.20 cmol·kg^-1-1.52 cmol kg^-1.Total K,exchangeable Mg are relatively even in soil aggregates of all particle sizes.The contents of soil Total N,available N,Total P,exchangeable Ca,exchangeable Mg in chuancha No 3 soil were lower than other cultivars.However,the exchangeable Na contend lower than other cultivars.And the contents of soil Total P,available K and exchangeable K in chuannonghuangyazao soil were higher than those in other cultivars.The highest contribution rates of micro aggregates to soil nutrient were in size 250-50μm.And the contribution rates of<1μm in FD soil were higher than those in other cultivars.