The Impact of Different Soil Water Content on Juglans regia Trees' Transpiration

Under the condition of controlled soil water content,transpiration rate,leaf temperature,room temperature,relativity humility,photo synthetically active radiation,stoma conductance of young walnut tree were determined.The results showed that different soil water contents affected obviously the daily change of the transpiration rate.The soil water content is below 8 %,the daily change of the transpiration rate is not obvious;However,the soil water content between 11 %-8 % can maintain trees' physiological function.Through the research of daily evapo-transpiration,we believe that when the soil water content is 11 %,the walnut tree can grow well,the lower limit value is 8 %.The regression analysis showed that when the soil water content is sufficient to grow walnut,there is a higher correlation between transpiration rate and environmental factors,on the contrary,a lower correlation between them.