Study on photosynthetic and traspiration chanacteristics of Medicago sativa in Prunus armeniaca-Medicago sativa agroforestry system

The photosynthetic and transpiration characteristics of Medicago sativa in Prunus armeniaca and Medicago sativa tree-grass system were studied using the Li-COR 6400 portable photosynthetic system.The results were as follows:(1)The diurnal variation of light intensity at the middle experimental site between the apricot rows demonstrated a curve with one peak,the same as the control,but the value of light intensity on the peak was lower than that of the control.The diurnal changes of light at the east and west sites were symmetrical.The peak of the former appeared in the morning,and that of the latter in the afternoon.The average diurnal light intensities at the middle site,east rows and west rows were 28.0%,61.9%,67.2% lower than that of the control,respectively;(2) Different light environments were simulated with shading treatments.The photosynthetic rate of Medicago sativa decreased steadily,and the value of light saturation point(LSP),light compensation point(LCP) and maximum net photosynthetic rate(Pmax) decreased,too;(3) The photosynthetic rate and transpiration rate of Medicago sativa in the tree-grass system declined,the regularity of their curves also changed.