麦田蒸腾需水量的计算模式

A CALCULATION MODEL ABOUT TRANSPIRATION WATER REQUIREMENT IN WHEAT FIELD

本文依据Ｐｅｎｍａｎ－Ｍｏｎｔｅｉｔｈ方法对小麦田田间蒸腾需水量计算方法进行了探讨，得出了一个改进的小麦蒸腾需水量计算模式，对模式中某些参数作了修订；并用中国科学院禹城综合试验站的观测资料对模式进行了计算，结果表明。

According to the study using Penman Monteith method, this paper gives an improved model for the calculation of transpiration water requirement in the well irrigated wheat field, it is CWR= Δ (R n-R sn )+ρC P/r ac Δ+γ1+r 0 ST r ac and the author makes some correction for the parameters in the model, such as r ac and r 0 ST r ac =r a 1+φ H ln z-dz 0where φ H is function of stability of boundary layer depending on Richardson number R i , r 0 ST =r 0 S/LAI , where the LAI is Leaf area indix and r 0 S is the minimum stamatal resistance of leaf on the top of Canopy. The testing result in the field at Yucheng Experimental Station shows that the mean value of the minimum stamatal resistance of canopy is about 40 s/m^60 s/m in the whole wheat growing season, the mean value of aerodynamic resistance of boundary layer is about 50 s/m in the full wet soil moisture condition, but it changes with the weather. The values of CWR of well irrigated field is close to the E T in the field and the values of T on the non full wet field are only 76% of E T . It means the given model in well irrigated condition is good to be used.