Study On Water-saving Irrigation Index For Greenhouse Cucumber During Fruit-bearing Stage

The experiments were performed on greenhouse cucumber(Cucumis Statirus L. CV. Jingchun2hao) in the horticultural station in Northwestern Agricultural University, to study the optimum irrigation index for greenhouse cucumber during fruit-bearing stage and some relative indexs,irrigation ammourt and irrigation frequencies,on the basis of previous research of soil water irrigation starting point.Under different soil water irrigation maxiums (80%, 85%, 90%, 95%, 100%), the following items were measured: plant height, stem diameter, leafarea,dry weight and fresh weight of stem, root activity, relative water content of root, bloom and fruit-bearing ratio, free water and bound water water content, free-bound ratio, chlirophl, leaf water pontential, net photosynthesis rate, transpiration rate, stomatic conductance, quality of cucumber, total yield and water effective utilization ratio,.The result showed: different soil water irrigation maximum had remarkable influence on growth of cucumber. Among the five treatments, there existed remarkable different in plant height with the growth, and was correlated with irrigation maximum which was line relation, stem diameter reached the highest point in 85-90 percent treatment, and there was no significant differences in these two treatments. Bloom and fruit-bearing ratio are best in 85-95 percents, dry weight of stem, root activity, chlorophyl and the average photosynthesis rate are all best in 90 percent. Root activity and the average photosynthesis were in cubic function curve relation with the irrigation maximums. Transpiration rate was line relation with the irrigation maximums. The regression equation and relative coefficient were:y光合 =2721.7x3-7817.x2+7430.1x-2323.6 R2=0.9982y根系活动=-311.23x3+787.662x2-658.47x+ 182.6 R2=0.998.y蒸腾=11.84x-5.4691 r=0.9347.In 90% percent, free water-bound water was highest and the metobolism of plant was active. Leaf water potential increased when the irrigation maximum increased. The effect on total yield was obvious and it was highest in 90 percent, but the foreperiod yield was highest in 85 percent. The total yield was curve relation with water irrigation maximums. The quality of cucumber was best in 90 percent, and it has remarkable effect on the content of soluable sugar ,but has no obvious effect on the content of Vc.By grey relational grade analysis on experiment under different irrigation maximum cf greenhouse cucumber during autumn delating period, It showed that the optimum water irrigation maximum was 90 percent during fruit-bearing stage under drip irrigation, the whole amount of irrigation was 1934.76m3/hm2,and the times was 10, thus we can improve water effective utilization and attain high yields good quality. If we can not keep 90 percent, the water irrigation also can be declined to 85 percent or raised to 95 percent.