温室滴灌条件下灌水下限对小型西瓜生长及耗水特性的影响

Effect of Different Irrigation Thresholds on Growth and Transpiration of Mini-watermelon in Greenhouse

研究了温室覆膜滴灌下不同土壤水分下限对小型西瓜根冠发育、品质以及耗水强度的影响。结果表明。高水分下限处理促进了小西瓜冠层发育，低水分下限处理表层O～20cm根系分生能力及根系活力较强；处理间品质指标无显著差异。各处理（灌水下限由高至低）小西瓜全生育期耗水量分别为179．2、172．5和156．7mm。果实膨大期温室相对湿度为其蒸腾的主要驱动力，建立的综合考虑土壤一大气环境要素对植株蒸腾影响的日光温室小西瓜蒸腾量（Tr）估算模型，可用于实际生产栽培中的灌溉决策管理。

The effects of different lower soil water limits on root-shoot development, quality and daily e vapotranspiration of mini-watermelon were investigated under mulch with drip irrigation. The results showed that the greatest shoot development was obtained by 85% of field capacity, hut root length density in 0~20 cm was higher in the low soil moisture treatment compared to other treatments. The quality inde- xes had no differences between the treatments. The total volumes of evapotranspiration in different treat ments（from high to low） were 179.2 mm,172.5 mm and 156.7 mm. The highest WUE was 13.94 kg/m3 in the treatment of 75%FC ~100%FC. Air relative humidity （Rh） was the most important factor to tran- spiration（Tr） in the fruit enlargement stage, and the regression equation was established based on Rh and soil moisure in 0~60 cm （00-60）, which represented the comprehensive influence of the circumstance in soil and atmosphere. The established model could be used for the management of irrigation decision in the actual cultivation.