The Research About Water Requirement Pattern And Irrigation Procedure

The experimental materials are 3-year-old pear jujube grafted seedlings,which are dwarfing and close planting ones. The experimet of the potted jujube is for one year,which startes on April 16, 2010 (transplanted) and ended on October 31 (defoliated). The whole growth period of pear jujubes could be divided into 5 growth stages—germination and frondescence stage , flowering and fruit bearing period, fruit expanding period,fruit maturation and deciduous period . The first four stages are studied in the paper. Based on the experimental studies, main climatic factors and growth index (growth of new shoots, jujube tree diameter, leaf area index) and physiological (photosynthetic rate, net photosynthetic rate, transpiration rate, stomatal conductance) under normal conditions with jujube are taken as a measure standards of the quality, the main results are as follows:(1)The whole growth period for the potted jujube is about 154d. The results of soil moisture dynamics under different water deficit levels show that the average daily water consumption under different treatments is followed: 5.6mm / d, 4.9mm / d, 4.4mm / d, and 4.1mm / d,that every phase of water consumption are: 870mm, 762mm, 686mm and 641mm.(2) Flowering and fruit bearing period and fruit expanding period,the average daily change of Pn and Gs under different treatments in normal conditions shows a single peak curve.The daily change of WUE is high in the morning and low in the afternoon.(3) In the deficit water conditions, the daily water consumption of the whole growth period is lower than the normal water conditions. The growth rate of newbranch and diameter compared with the normal water conditions has slowed down;With less soil moisture, leaf area growth is slow and the number of branches is reducing and the single leaf area of each branch level also decreases; The number of buds under different water deficit levels with time first is increasing and reachs the maximum on July 2nd,and then decreases.With the decreasing of soil water content , the flowering date also will shorten for jujube trees.(4) Experimental study through the year, initially obtaining for the water requirement of jujube in germination and frondescence stage,flowering and fruit bearing period,fruit expanding period and fruit maturation, which is about 82 cubic meters per 667 square meters,205cubic meters per 667 square meters, 133.4 cubic meters per 667 square meters and 92 cubic meters per 667 square meters,the water intensity in different stage is 4.1 milimeters per day, 5.8 milimeters per day, 5.0 milimeters per day and 4.6milimeters per day. (5) The experiment find that the appropriate soil moisture content of weigh in the growth of jujube is alike, which is 15.2 to 19.8 percent during the first and fourth stage,which is 15.2~ 22.1% during the second and third stage.(6) Reserching for the potted Jujube plants by year ,we can draw that the water requirement of the whole growth is 686 to 762mm.The low limit is adopted in the first and fourth stage, irrigation period of which is 10d and irrigation frequency of which is 3 to 4 times;However, upper limmit is chosen during the second and third stage.During both period, irrigation period of which is 5d and irrigation frequency of which is 5 to 6 times. A total of irrigation throughout the growth period of 18 times. Under normal circumstances, jujube trees in flowering and fruit bearing period set in 2 times and 1 times in fruit expanding period. However, depending on rainfall of different years ,timely irrigation is needed.Usually years, in germination and frondescence stage and fruit maturation, when the water content of soil weight is less than 15.2% (representing 65% of field capacity), the irrigation of a light water is required.