Water Use Strategies of Caragana korshinskii and Populus bolleana in Pure and Mixed Plantations in the Eastern Sandy Land of the Yellow River in Ningxia
[Objective]This study aims to explore the water use strategies of Caragana korshinskii and Populus bolleana in pure and mixed plantations,and analyze the water use relationship of the two species in the mixed plantation,influencing factors of soil water utilization in different plantations,and the effects of different plantations of C.korshinskii and P.bolleana on soil moisture environment in the eastern sandy land of the Yellow River in Ningxia,China,so as to provide theoretical guidance for the stand structure optimization and regulation of shelter forests in arid areas.[Method]In the growing season of 2018(May-October),the pure plantations of C.korshinskii and P.bolleana and the mixed plantation of C.korshinskii+P.bolleana in the eastern sandy land of the Yellow River in Ningxia,China,were used as the study object.The stable isotope technique of hydrogen and oxygen and the IsoSource mixed model were used to analyze water source of C.korshinskii and P.bolleana in pure and mixed plantations,and the similarity proportion index(PS index)was used to calculate the water use relationship of two species in the mixed plantation.Soil water content,soil nutrients and root biomass were simultaneously monitored,and the structural equation model(SEM)was used to quantify the impact of different factors on soil water utilization of two species.The effects of the two species in different plantations on soil water environment were analyzed by calculating soil water storage,soil water deficit and soil water consumption rate.[Result]1)Throughout the growing season,the main water sources of C.korshinskii in pure and mixed forest were the same,while that of P.bolleana in pure and mixed forest were opposite.2)The PS index of C.korshinskii and P.bolleana in the mixed forest was 62.75%throughout the growing season,and there was a weak competitive relationship on water use between the two species.The PS index and water sources of the two tree species was various in different periods of the growing season,and the drought could be dealt with by the separation of water use in time and space.3)Soil water content had the highest total effect on soil water use utilization in the three forests.Soil water content and soil nutrients were significantly negatively correlated with soil water use utilization of C.korshinskii in pure forest(P＜0.01),significantly positively correlated with soil water use efficiency of C.korshinskii in mixed forest(P＜0.01),and significantly positively correlated with soil water utilization of P.bolleana in both pure forest and mixed forest(P＜0.05).Root biomass was significantly positively correlated with the soil water utilization in the three forests(P＜0.05).4)The soil water storage of mixed forest was higher than that of pure forest of C.korshinskii and P.bolleana,but the soil water deficit and soil water consumption rate of mixed forest were lower than those of pure forest of C.korshinskii and P.bolleana.[Conclusion]The water use strategy of C.korshinskii in pure and mixed forest is basically the same,while P.bolleana in pure and mixed forest has opposite water use strategies.In the mixed plantation,C.korshinskii and P.bolleana cope with drought through the difference of water use efficiency in time and space,and mixed plantation can reduce the risk of soil dryness compared to pure forests.The main influencing factors of soil water utilization of the two species in the pure and mixed plantations are soil water content and soil nutrients.
water sourcewater use relationshipstable hydrogen and oxygen isotopesstructural equation modelsoil water deficit
万方数据
维普
