温室芹菜需水强度与作物系数研究

测定作物需水量是进行合理灌溉的基础,确定作物系数是借助气象参数便捷预测作物需水量的前提。本研究借助水量平衡法和Penman-Monteith温室修正模型对芹菜进行研究。试验结果表明:温室芹菜需水强度和参考需水强度均呈“增加-降低-增加”的波动增加趋势,累积需水量和参考累积需水量均呈直线函数增加趋势,作物系数呈移动平均函数变化趋势。进一步将全生育期划分为4个阶段发现,苗期、叶丛初期、中期和后期的需水强度分别为1.128、1.917、1.405和2.212 mm/d,需水量分别为30.46、51.77、63.23和79.63 mm,作物系数分别为0.418、0.385、0.571和0.565。基于2 h采集频率的气象数据结果还表明,4个生育期的参考需水强度日变化曲线均呈“单峰型”,早晨8点开始逐渐升高,午间12点至下午2点达到峰值,以后逐渐降低,至晚间10点左右回落至初始值。

Analysis of Water Requirement Rate and Crop Coefficient for Greenhouse Celery Under Well-irrigated Condition

Analysis on laws of crop water requirement provides basis for rational irrigation and ascertaining the crop coefficient lays foundation to conveniently forecast crop water demand with meteorological parameters recorded by automatic weather station. In this study, celery water requirement law is studied by using field water budget and modified penman-monteith model. The results indicates that, the actual and the reference water requirement rate all shows “increase-decrease-increase” volatility increasing trend, the actual and the reference cumulative water requirement all exhibites a linear function increasing trend, while the crop coefficient behaves a moving average function trend. By di-vides the whole growth period into four different stages, it is found that the actual water requirement rate at seedling, early-phyllome, mid-phyllome and later-phyllome stage are 1.128, 1.917, 1.405 and 2.212 mm/d, the corresponding water requirement at four stages are 30.46, 51.77, 63.23 and 79.63 mm, respectively, and the corresponding crop coefficient are 0.418, 0.385, 0.571 and 0.565, respectively. Modified P-M model analysis of meteorological data based on 2 h acquisition frequency shows that, the daily water requirement rate at four growth sta-ges all shows “single peak” curvilinear trend, which begins to increase at am 8 ∶ 00, reachs peak value between 12 ∶ 00 and 14 ∶ 00, then gradually reduces, and backs to initial value at 22 ∶ 00.