中文摘要：

作物系数是在没有实测需水量资料情况下,用参考作物蒸发蒸腾量来估算实际作物蒸发蒸腾量方法中重要的参数之一.根据实测气象数据计算出的参考作物蒸发蒸腾量和时域反射仪测得的番茄需水量,利用单作物系数法得到番茄作物系数K.通过对作物需水量和作物系数K的变化及影响因素进行分析,结果表明：温室膜下滴灌番茄作物需水量与温度、辐射呈正相关,而作物系数Kc与温度、辐射的线性关系不明显.对已求作物系数的可靠性进行验证,结果表明模型预测值和实测值的相对误差为8.2％,模型有效性指数达到89.3％,模型合理有效.研究成果对日光温室膜下滴灌作物需水量的计算及其灌溉制度的制定具有一定的参考价值.

英文摘要：

Crop coefficient （Kc） is one of the most important parameters in the reference crop evapotranspiratlon method to esumate the actual crop evapotranspiration. According to the various meteorological data measured in sunlight greenhouse, the reference crop evapotranspiration is calculated. Combined with the water requirement of greenhouse tomato measured directly by Time Domain Ref- lectometry, Kc is calculated by single coefficient approach in this paper. Through an analysis of the annual change of water require- ment, Kc and three influencing factors, calculation model of water requirements with the crop coefficient approach is built and valida- ted. The results show that temperature and radiation have a larger effect on water requirement, however crop coefficient have a non- linear correlation with them. The relative error and the index of simulation effectiveness of the calculated values and the measured values were 8.2 % and 89.3% respectively, which indicated that the model is reasonable and effective. The results have some refer ence values for the calculation of crop water requirement with irrigation under mulch in greenhouse and the development of its irriga- tion system.