黄土高原水蚀风蚀交错区三种植被蒸散特征

利用称重式蒸渗仪结合Penman-Monteith公式研究了黄土高原水蚀风蚀交错区苜蓿、柠条和茵陈蒿3种植被不同时间尺度的蒸散特征,分析了植被株高、盖度和降水等因子对蒸散的影响并确定了作物系数(KC).结果表明:Logistic三参数模型可以较好拟合3种植被株高、盖度随时间的变化情况并确定了模型的参数.3种植被逐日蒸散变化受降水量的影响波动明显,反映了土壤水分状况控制条件下的蒸散过程.其月蒸散量的季节性差异均不明显,研究时段内总耗水量分别为苜蓿316 8mm、柠条317.7mm、茵陈蒿361.9mm,均高于同期降水量.苜蓿和茵陈蒿初期、中期和后期的KC分别为0.48、0.54、0.42和0.58、0.67、0.62,柠条初期和中期的KC为0 45、0.57,均高于当地典型农作物谷子的KC.

Evapotranspiration of three types of plants in water-wind erosion crisscross regions in the Loess Plateau

In this study, lysimeters were used to measure evapotranspiration (ET) of Alfalfa, Caragana, and Artemisia capillaries in water-wind erosion crisscross regions in the Loess Plateau. The measured ET and Penman-Monteith equation were used to determine crop coefficient (KC), and the effects of vegetation height and coverage and precipitation on the ET were analyzed. The results show that the Logistic model can be used accurately to simulate the changes of the height and coverage of the three types of vegetation. The daily ET variations of these three types of vegetation were significantly affected by precipitation, indicating that evapotranspiration processes were controlled by the soil water content in the arid region. There was no meaningful difference in the monthly ET among the three types of vegetations. The total ET of Alfalfa, Caragana and Artemisia capillaries were 316.8mm, 317.7mm and 361.9mm, respectively. The crop coefficients of Alfalfa in initial, middle and end growing periods were 0.48, 0.54, and 0.42 respectively. The crop coefficients of Artemisia capillaries in initial, middle and end growing periods were 0.58, 0.67 and 0.62 respectively. Crop coefficients of Caragana in initial and middle growing periods were 0.45 and 0.57 respectively and those values are higher than that of local typical food crop.