Effects of Regulated Deficit Irrigation (RDI) on the Growth, Yield and Quality of Greenhouse Cucumber

[Objective]The studyaimed to find the optimumRDI project and supply theoretical basis for water-saving and high-yield cultivation.[Method] The greenhouse cucumber was treated with lower-limit irrigation combination(45 %￣75 %) of different soil water content in different growing stages in 2006 and some biological indexes,yield,fruit quality and moisture utilization efficiency of plant were determined under different irrigation conditions.[Result] The irrigation lower-limit of greenhouse cucumber in first flowering was 60 % of field moisture capacity and the soil water content was kept at 65 %￣90 % offield moisture capacityin fruitingstage,which was most ideal toenhance fruit quality.In this treatment,the deoxidize sugar,total soluble sugar,Vc and soluble protein contents in fruit were 39.94 %,31.34 %,3.14 % and 5.47 % higher respectivelythan CKand the moisture utilization efficiencywas 9.57 % higher than CK.The water-savingeffect ofkeepingat 60 %￣90 % offield moisture capacity was most significant,being 18.84 % higher than CK,but the fruit quality was obviously worse than that of 65 %￣90 % of field moisture capacity.[Conclusion] The water deficit in different stages was favorable for increasing plant drought resistance.The moderate draught in fruiting stage could enhance moisture utilization efficiency of plant significantly and reduce irrigation amount,and the yield had no significant decrease.