基于土壤水分承载力的防风固沙林密度配置格局与防护效应

项目名称： 基于土壤水分承载力的防风固沙林密度配置格局与防护效应

项目编号： No.31460221

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 农业科学

项目作者： 马瑞

作者单位： 甘肃农业大学

项目金额： 50万元

中文摘要： 干旱沙区，绿洲外围大面积的防风固沙林在成林过程中往往因土壤水分亏缺而大量衰亡，因此，营建时需要在密度和防护效益间求得平衡。有研究表明，气流在孔隙度不同的连续介质中通过时，流场会发生显著变化，进而改变能量交换强度。据此，可以通过林分密度的非均匀配置,在降低林带平均密度的同时保证有效密度。在我国干旱沙区，绿洲所受主导风确定，且随着与绿洲距离的增大，土壤水分条件变差。基于此，本项目将在野外观测与风洞模拟的基础上，对林带密度沿主导风向的非均匀配置格局及其防护效益与机理进行系统研究。首先，通过野外调查与测定，探索植株生长状况和林分密度对土壤水分条件的响应，凝练适宜密度；在此基础上，通过风洞模拟实验，明确沿主风向密度非均匀配置格局及林带的防护效益与机理；最后，通过对绿洲外围关键生态因子与防护效益的耦合研究，构建密度配置数理模型,凝练适合荒漠绿洲外围生境条件的防风固沙林密度配置体系，为建植提供技术策略。

中文关键词： 防风固沙林；土壤水分承载力；密度配置；耦合效应；数理模型

英文摘要： Shelterbelts have been planted in a large scale in oasis peripheries in Northwest China to shelter oases in a long-term from shifting sands and to pretect the land surface from wind erosion. But it presented a decline effects for the deficit of the soil water in the grow process. So, the balance between the density and protection benefits needed to be solved for the construction of the oasis windbreak and sand-fixation forest. Certain researches showed that when the airflow travel through a continuous medium which composed of various porosity, the flow field changed significantly, and so changed the energy exchange intensity. Accordingly, the consumption of energy of the airflow will also be changed when the wind-sand flow cross through a forest belt which with a non-uniform density distribution. However, the application of plantation of windbreak and sand-fixation forest with a inhomogeneous density distribution still belong to blank, and till now,no system study related to shelterbelt has concerntrated on the effectiveness and protection mechanism of the windbreak and sand-fixation forest with a non-uniform density distribution. In the arid desert area of China. the oasis is determined by the prevailing wind and as the increase of the distance from the oasis, the soil water condition gets worse. Based on this, the basis theory and methods of desert ecology and aeolian physics will be used in this project, the response mechanism between the forest density and soil water and plant growth status will be got through a field investigation and then to sieve out a suitable density. Additional, the protection mechanism and protection benefits of the forest which be arranged with diffenert density along the wind direction will be explored by wind tunnel simulation experiments. And then, establish a mathematical model about the density distribution and the configuration system of density of windbreak and sand-fixation forest in the periphery of oasis will be explored by the study on the coupling effect of water, soil, climate, and protection benefit.The results can be applied to forest plantation as a technology strategy in transitional zones.

英文关键词： Shelter forests against wind and for fixing sand;Carrying capacity of soil water;Density distribution;Combined effects;Mathematical model