无压灌溉日光温室番茄作物-皿系数研究

Study on crop-pan coefficient of greenhouse tomato under non-pressure irrigation

以-25 kPa作为土壤水势临界值,将作物—皿系数（Kcp）设为0.2,0.4,0.6,0.8,1.0,1.2六个处理,研究了不同灌溉水量时的番茄产量、品质和灌溉水利用效率。通过经济效益评价,研究了杨凌地区无压灌溉温室番茄获得最高经济效益时的作物—皿系数。通过张力计读数变化规律,研究了利用张力计测量无压灌溉湿润体内土壤水势的特点。研究结果表明,Kcp为0.2-0.8时,灌溉水量的增加对番茄产量影响不大;Kcp为1.0-1.2时,灌溉水量的增加能显著提高番茄产量和果实大小;Kcp为0.2时的灌溉水量能极显著提高番茄的灌溉水利用效率。在综合考虑了杨凌地区水价、番茄使用目的和市场价格波动规律后,Kcp取值1.2能获得最高的经济效益。作物—皿系数法计算灌溉水量时的滞后性特点和张力计埋设位置,是判断利用张力计监测土壤水势临界值方法有效性的两个重要因素。

Crop-pan coefficientis the ratio between crop water consumption and pan evaporation. Using - 25 kPa as the soil water potential threshold, and designing six treatments for crop-pan coefficient Kcp = 0. 2, 0.4,0. 6, 0. 8, 1. 0, 1.2, study was made on tomato yield, quality and irrigation water use efficiency under different irrigation water amount. The crop-pan coefficient which acquired highest economic effectiveness was studied through the economic effectiveness analysis, while the measurement character of soil water potential using tensiometers was studied through the tensiometer reading. The results indicated that when Kcp values was from 0.2 to 0.8, the irrigation water amount had no influence on tomato yield, but when Kcp values was from 1.0 to 1.2, the irrigation water amount had significant effect on tomato yield. When Kcp value was 0.2, the irrigation water use efficiency was improved significantly. After considering water price, tomato using aim and market price in Yangling district, there was the highest economic effectiveness when Kcp was 1.2. The hysteresis quality of irrigation water amount calculation using crop-pan coefficient and the buried position of tensiometer were main factors to estimate the validity of tensiometer measuring the soil water potential threshold.