Study On The Influence Of Land Use And Landscape Position On The Distribution Of The Phosphorus In The Soil

Zhangdigou small watershed is a typical watershed of the low hills mountainous on theupstream of Danjiang watershed. To understand the influence factors of the spatial pattern ofthe soil phosphorus in the small watershed from many scales can provide scientific proof foragriculture structure adjustment, effective utilization of soil phosphorus and water cleaning inDanjiang watershed. Based on GIS, this paper discussed the spatial distribution characteristicsof soil phosphorus in Zhangdigou small watershed by using the geostatistics method, andanalysis the content of various components of soil phosphorus in the research area, revealedthe spatial variation patterns of the soil phosphorus on small watershed scale, and futheranalyzed the influence of the land use and landscape position for the spatial distribution of thesoil phosphorus. Results showed that,(1) The content of TP, Olsen-P and organ phosphorus in the soil of the research arearespectively were688.21mg/kg,10.36mg/kg and87.46mg/kg, the contents order of thecomponents of inorganic phosphorus was Ca10-P>Fe-P>Ca8-P>Al-P>O-P>Ca2-P. TheOlsen-P and Ca10-P in the soil of the research area had a strong spatial correlationship, whileother components had a moderate spatial correlationship. There was some certain regularityon the spatial distribution of the soil phosphorus. The spatial distribution characteristics of thecontent of TP, Olsen-P, organ phosphorus, Ca2-P,Ca10-P and Al-P were to take the irregularplaques near the channel as high value area to be the center, and then gradually reduced as along pattern. The spatial distribution characteristics of the the content of Fe-P in soil wasirregular ribbon pattern as the uphill and downhill to be the high value area, and constantlydigressive to the surrounding extension. The spatial distribution characteristics of the contentof Ca8-P was opposite with Ca2-P. While the spatial distribution characetristics of the O-Pcontent was to take the northwest-southeastern channel as the boundaries, and the content washigher in its southeastern area while lower in northwestern area as a stripped feature.(2)The area of the woodland and farmland took a high percentage in all of the land use inZhangdigou small watershed, which was followed by the area of orchard. The content of TP and organophosphorus in soil in the four kinds of land use had no significant difference, whilethe content of Olsen-P had a very significant difference with land use. The content of Olsen-Pin soil was highest in farmland, its average content was10.84mg/kg, while lowest ingrassland. It was very significant difference with other three kinds of land use. The content oforgan phosphorus was at a range of70.15⁸4.97mg/kg, and the change pattern was similarwith TP. The land use of the highest content of Ca₂-P and Fe-P in soil was farmland, followedby orchard, woodland and grassland, while the content of Ca₈-P was opposite with Ca₂-P. Thecontent order of Al-P was orchard>grassland>farmland>woodland. The content changepatterns of Ca10-P and O-P were the same with each other, which was highest in orchard andfarmland while lowest in woodland.(3)Ca8-P in soil was positively related with the elevation of the research area, and otherswere negatively related. For slope, Ca8-P and Al-P were positively related with it, whileothers were negatively related. Olsen-P, Ca8-P, Ca10-P and O-P in soil were positively relatedwith the aspect of the research area, it showed that the content increased gradually from northto south with the the azimuth clockwise, while the content of TP, organ phosphorus, Ca₂-P,Fe-P and Al-P were negatively related with aspect.(4)The content of TP, Olsen-P, organ phosphorus and inorganic phosphorus in theresearch area were were gradually decreasing with the increase of the elevation. The results ofvariance analysis showed that the content of TP in soil in different elevation were verysignificant differences, while Olsen-P, organ phosphorus, and Ca₂-P, Ca₈-P, Fe-P and O-P insoil in different elevation positions were significant differences. The content of Ca₁0-P in soilwere significant difference in elevation toe with other elevation positions. The content of O-Pin soil was significant difference between every elevation position except the uphill bit.Soil phosphorus in the research area had a decreasing trend with the increase of slope,and the changes were very gentle. Soil potential phosphorus Ca8-P and Al-P had an oppositechange trend with each other. The results of variance analysis showed that Olsen-P had asignificant difference between steep slope, delay ground and terrace. The content of Fe-P hada significant difference between slope land and others. While the content of Al-P had asignificant difference among delay ground and terrace, slow steep slope and steep slope.The contents of TP, Olsen-P and organ phosphorus in soil were all highest in shady slope.The results of variance analysis showed that TP in soil had a significant difference betweenfloat slope, sunny slope, semi-sunny slope and other two aspect. The content order of thecomponents of phosphorus was shady slope>sunny slope≈semi-sunny slope>semi-shady slope>float slope. The results of variance analysis showed that soil inorganic phosphorus hada certain significant in every aspect, while Ca₂-P in soil was not significant in any direction.