应用农田水量平衡原理计算三种蔬菜的需水量和作物系数

根据田间水分和肥料最优控制下测定的土壤水分，利用农田水量平衡原理分别计算了花椰菜、苋菜和菠菜生长期内的作物需水量。根据作物需水量和气象资料计算的参考作物蒸散量，计算3种蔬菜在不同生育期内的作物系数。结果表明，花椰菜、苋菜和菠菜在整个生长期内的需水量分别为223．8mm,144.9mm和148.1mm；作物系数的平均值分别是0．68，0．94和0．65；除苋菜的作物系数与叶面积指数的拟合关系相关性不显著外，花椰菜和菠菜的作物系数与叶面积指数呈对数函数关系。

Evaluating Crop Water Requirements and Crop Coefficients for Three Vegetables Based on Field Water Budget

According to the measured soil moisture under the optimal soil water and fertilizer conditions, crop water requirements (ETc) of three vegetables were calculated by soil water budget model. Crop coefficients (Kc) of cauliflower, amaranth and spinach during growth period were evaluated based on the determined ETc and reference evapotranspiration (ET0) by Penman-Monteith procedure. The crop water requirements for cauliflower, amaranth and spinach were 223. 8 mm, 144. 9 mm and 148. 1 mm separately; the mean Kc for above vegetables were 0. 68, 0. 94 and 0. 65 mm separately; the Kc value has a logarithmic function to leaf area index for experimented crops except for amaranth.