Based on the field monitoring data, the daily transpiration, monthly transpiration, water requirement and their season changes of black locust forest with 1.5 m×6 m, 1.5 m×3 m density in Fangshan County runoff forest field were studied using Penman-Monteith equation, combining with the data of weather observation and water surface evaporation.
According to the conventional meteorolog observation data and the water surface evaporation of 20m 2 experimental pool in Changji, it analysed the effective degree of different meteorological factors on the water surface evaporation, and obtained the conversion coefficient of water surface evaporation of E 601 and 20 Evaporation implements, set up the experience formula of calculating the water surface evaporation.
Applying stepwise regression (the fiducial degree is 0.05), the equation of soil moisture content (y) can be expressed: y= 486. 709+ 2. 061X4 + 1.786X9 - 4.451X10 (R =0.830,X4 :content of waterstable granule, X9:rain fall before 15d, X10: evaporation from water surface).
This paper studies the effect of weather change on regional evaporation by analyses change trend of reference crop evapotranspiration(ET0), and the effect of irrigational agriculture development on irrigation district actually measured evaporation from water surface.
Based on the lysimeter data from the experimental station on ground water balance in Zhengzhou, the relationship between phreatic water evaporation and weather,water table depth, soil and precipitation recharge is analyzed.
The results show: The farmland and shelter forest can improve the local conditions,reducing the wind speed,increasing humidity of air and soil,regulating temperature of air and soil,reducing evaporation of water surface,breaking wind and fixing shifting sand,reduce winderosion. As a result,the protective effect in 3 H～5 H is the best.
Using the water-balance method, the authors studied the water consumption of tomato (Lycopersicon esculentum Mill.) and the relationship between evapotranspiration and water surface evaporation measured with 20?cm pan.
The accumulative value of evapotranspiration is approximately equal to the accumulative value of water surface evaporation measured using 20?cm pan.
Evaporation may be approximated using the mean monthly pan evaporation or free water surface evaporation data.
It was also established that there was a corresponding increase in open water surface evaporation during this period.