农林复合系统对环境质量调控作用研究

A Study on the Effect of Agroforestry on Environmental Quality

运用同位素示踪法并结合野外实测对农林复合系统的环境质量调控作用进行了研究,结果表明:农林复合系统中由于林木的存在,其固定CO2能力是单一的农业系统的1.6～2.1倍,农林复合系统大气中CO2浓度平均比单一的农业系统低55～95mL.m-3。杨树与柳树以及小麦和玉米对N2O具有一定的吸收作用。农林复合系统内外,甲烷浓度值十分接近,作物和大气间的CH4气体未表现出明显的交换作用。在沙质土壤类型区,农林复合生态系统是减少降尘的直接原因,能够有效地减少尘埃输送量,同时能减少降尘量达20%～60%;防风效能、乱流交换强度、土壤湿度是决定降尘量大小的主要因子。

The effect of agroforestry on environmental quality was studied by isotope trace technique and the field experimentation,the results showed:(1)The capacity of fixing CO 2 of the agroforestry was 1.6～2.1 times as much as that of the single agricultural system because of the existence of tree. On an average,the content of CO 2 in the agroforestry was 55～95 mL·m -3 lower than that in the single agricultural system.(2)Poplar,willow,wheat and maize could absorb N 2O by an certain degree.(3)There were no significant difference about the CH 4 content between inside and outside the agroforestry system,i.e,there was no obvious CH 4 gas exchange between crops and atmosphere.(4)In the sandy soil area,agroforestry could reduce the transporting dust capacity effectively,and reduce the falling dust capacity by 20%～60%.Wind protection effect,intensity of turbulent current exchange and soil moisture were the main factors that determined the falling dust capacity.