土壤持续干旱条件下早开堇菜与草地早熟禾对土壤水分利用特征的比较研究

在2006年7月至9月期间．研究了在土壤持续干旱条件下早开堇莱种群和草地早熟禾种群的蒸腾失水过程和对土壤水分利用的特征。结果表明：（1）在植物只发生蒸腾作用的情况下，草地早熟禾种群和早开堇菜种群平均存活天数分别为46d和41d；在植物发生蒸散的情况下，两者平均存活天数分别为23d和24d。（2）在土壤含水量高于75％～80％田间持水量时。草地早熟禾种群的日蒸腾量大于早开堇菜种群；在土壤含水量波动于30％。80％时，早开堇莱种群的日蒸腾量高于草地早熟禾。（3）早开堇莱的萎蔫系数小于草地早熟禾。（4）在持续干旱条件下早开堇菜和草地早熟禾种群对土壤水分利用率分别为78．03％和70．00％；在0—5cm，5-10cm，10-15cm^3个土层上．早开堇莱种群的水分利用率都高于草地早熟禾。

Comparative Study on Soil Water Utilization Characteristics of Viola Poapratensis and Poa Pratensisl L.Populations under Long-term Soil Drought Stress

The evapo-transpiration dynamics and soil water utilization characteristics of Viola poapratensis and Poa pratensisl populations were studied under long-term soil drought stress from July to September in 2006.The results showed:(1)the average survival days of Poa pratensisl and Viola poapratensis populations were 46d and 41d,respectively,under evapo-transpiration,in contrast,the average survival days were 23d and 24d,respectively,in nomal conditions.(2)The evapo-transpiration per day of Poa pratensisl population were higher than that of Viola poapratensis when soil moisture were beyond 75% and 80%.But when soil water fluctuated from 30% to 80%,the evapo-transpiration per day of Viola poapratensis were higher than Poa pratensisl population.(3)Wilting coefficient of Viola poapratensis was lower than that of Poa pratensisl population.(4)The soil moisture utilization rate of Viola poapratensis and Poa pratensisl population were 78.03% and 70.00%,respectively,under long-term soil drought stress The soil water utilization rate of Viola poapratensis were higher than that of Poa pratensisl population.among 0~5cm,5~10cm and 10~15cm soil layers.