Study On Composition And Stability Of Soil Aggregates And Distribution Of Fluoride And Aluminum Fractions In Soil Aggregates Under Tea Plantation Cultivars

Tea tree is called polyaluminum fluoride plant.The content of aluminum fluoride in tea depends on the content of active aluminum fluoride in soil which is easily absorbed by tea tree.Different forms of aluminum and fluorine can not only transform each other,but also have different effectiveness and agglomeration.The particle size affects the distribution of aluminum fluoride.Therefore,it is of great significance to study the changes of aluminum and fluorine contents in the soil aggregates of tea gardens in the process of understanding the sustainable use of tea gardens and the safe production of tea.This study is based on different tea planting soils in Zhongfeng Township,Yashan District,Ya'an City(?Fuding Dabai?FD?,Chuancha 3?CC?,Chuanmu 217?CM?and Chuan Nong Huang Bu Zao?CN??The research object combines field investigation and indoor analysis to study the distribution characteristics of aluminum and fluorine in tea garden soil aggregates from the low mountain hilly area in western Sichuan from the perspective of soil non-water stable aggregates and water-stable aggregates.To understand the contribution rate of aggregates of various particle sizes in soil non-water-stable agglomerates and water-stable aggregates to various forms of aluminum fluoride,revealing that aluminum and fluorine forms in soil aggregates have responses to different tea varieties,and are tea gardens.The scientific formulation of soil management measures and the effective implementation of the project of returning farmland to tea provide a theoretical basis.The research results are as follows:?1?Soil non-water-stable aggregates of different tea-cultivating varieties were mainly>5 mm,with content ranging from 60.52%to 76.49%;water-stable aggregates were>5 mm and<0.25 mm The main path.Among the four planting tea varieties,the non-water-stable and water-stable aggregates with the highest particle size>5 mm were planted in Fuding,and the contents were 74.94%and 37.15%,respectively.?WSAR?,average weight diameter?MWD?and geometric mean diameter?GMD?were the lowest,0.72,0.0475⁵.61,0.0222⁴.10,fractal dimension?D?,C_S and C_E were larger,showed the planting of Fuding Dabai.It was beneficial to the formation of large particle size aggregates in the soil and has good erosion resistance.?2?Soil total aluminum?T-Al?and residual aluminum?Res-Al?were mainly distributed in<0.25 mm non-water-stable agglomerates,which were 62.06⁸6.21 and51.77⁷8.00 g kg^-1,respectively;soil water soluble Both aluminum?Ws-Al?and exchanged aluminum?Ex-Al?were enriched in<0.5 mm non-water-stable agglomerates,1.90³.40 and 84.38²97.37 mg kg^-1,respectively;iron-manganese bound aluminum?Fe/Mn-Al?was abundant in>5 mm non-water-stable agglomerates,which was606.13⁶47.50 mg kg^-1;organic-bound aluminum?Or-Al?was mainly distributed in<2mm non-water stability.In the agglomerate,it was 22.76-35.08 mg kg^-1.Soil T-Al and Res-Al were enriched in water-stable aggregates with a particle size of<0.5 mm,and the distribution of other forms of aluminum in water-stable agglomerates was approximately the same as that of non-water-stable agglomerates.The aluminum forms of non-water-stable agglomerates of different plant-tea varieties were mainly in the residual state.The distribution of aluminum in the other forms was as follows:Fe/Mn-Al(431.25⁶47.5 mg kg^-1)>Ex-Al(73.44²97.37 mg kg^-1)>Or-Al(62.44¹42.28 mg kg^-1)>Ws-Al(1.31³.40 mg kg^-1).The contents of T-Al,Ws-Al,Ex-Al,Fe/Mn-Al and Res-Al in the soil of planting Chuancha 3 were higher than those of other tea varieties.?3?Soil perfluorine?T-F?,water-soluble fluorine?Ws-F?,exchangeable fluorine?Ex-F?,and residual fluorine?Res-F?were mainly distributed in<0.5 mm non-water-stable agglomerates.They were 332.01⁴97.00,0.79¹.11,1.00¹.62 and 320.46⁴85.19 mg kg^-1,respectively.Soil iron-manganese bound fluorine?Fe/Mn-F?and organically bound fluorine?Or-F?were mainly concentrated in>2 mm non-water-stable agglomerates,which were 4.62⁵.11 and 5.89⁷.54 mg kg^-1,respectively.T-F was enriched in water-stable aggregates of<1 mm particle size,Res-F was mainly concentrated in water-stable aggregates of<2 mm,and the distribution of other forms of fluorine in water-stable aggregates and non-water-stable agglomeration The body was roughly the same.The forms of fluorine in non-water-stable aggregates of different plant-tea varieties were mainly Res-F,and the distribution of fluorine in other forms was Fe/Mn-F(4.30⁷.55 mg kg^-1)?Or-F(2.29⁴.85 mg kg^-1)>Ws-F(2.42⁴.97 mg kg^-1)?Ex-F(0.62¹.11 mg kg^-1).>5 mm particle size non-water-stable agglomerates,the total amount of fluorine and its contribution rate were much higher than the remaining particle size,up to 27.88⁷7.80%,while the contribution rate of water-stable agglomerates was>5 mm and<The highest particle size of 0.25 mm.The contents of T-F and other forms of fluoride in Fuding white soil were higher than those in other varieties.