Effects of different land use practices on soil N fractions and enzyme activities in the Loess Plateau of Longzhong
[Objective]To study the distribution characteristics of nitrogen and enzyme activities in soils of the Longzhong Loess Plateau due to land use change and the effects on regional soil quality and microen-vironmental changes.[Method]Soils from five different land uses(abandoned land,spruce woodland,sea buckthorn woodland,alfalfa land,and wheat land)in the Loess Plateau area of Longzhong were used as re-search objects to determine and analyze the content of soil nitrogen fractions and the characteristics of changes in soil enzyme activity.[Result]Among the five land use approaches,spruce woodlands in the 0～60 cm soil layer significantly increased soil total and microbial nitrogen contents,while the abandoned land and wheat land had relatively low content.Soil ammonium and nitrate nitrogen contents were both highest in the alfalfa field.In addition,the content of soil N fractions varied between soil layers,its content distribu-tion decreases with increasing soil depth.Soil urease,protease and nitrate reductase activities decreased with soil depth,except for nitrite reductase activity which showed an increase with soil depth.Soil urease ac-tivity increased significantly in spruce woodland and buckthorn woodland in the 0～60 cm soil layer com-pared with the abandoned land,and decreased in alfalfa and wheat land.The protease activity was optimal in spruce woodland and lowest in abandoned land.Nitrate reductase activity was highest in alfalfa land,fol-lowed by spruce and buckthorn woodland,lowest in wheat land.The nitrite reductase activity in the differ-ent land use patterns from strong to weak was in the order of alfalfa land,abandoned land,sea buckthorn woodland,spruce woodland,and wheat land.Correlation analysis showed that there was some significant positive correlation between soil N fraction and enzyme activity(P<0.05).[Conclusion]Land use was an important factor influencing soil nitrogen content and soil enzyme activities,with an increase in soil nitrogen content,soil enzyme activities would also increase,especially in spruce forest and alfalfa field.
land use patternLoess Plateau of Longzhongsoil nitrogen componentsoil enzyme activi-ties
万方数据
维普
