| Aiming to solve the problem there’s indeterminary supplement irrigation procedure for old-gravel mulched field jujube trees cultivating in middle arid region of Ningxia, a field experiment which is based on theory of water saving irrigation, soil hydrodynamic, and crop science, has been finished with different irrigation limit. We used tubular TDR system, ruler, fernier caliper, electronic scales, Li-6400XT protable photosynthesis measuring system, G327 hanging temperature and humidity meter, hanging rain gauge, drying oven, and other experiment tools, to observe root zone local moisture, canopy biomass, yield, volume of fruits, and other growth indicators of jujube trsss, to observe net photosynthetic rate, stomatal conductance, water use efficiency, and other physiological indexes of jujube trees, to observe canopy temperature and humidity, rainfall and other meteorological factors, in the whole growth stages.Then we finished research about soil moisture dynamic, research about growth conditions with different irrigation limit, research about the photosynthetic characteristics with different irrigation limit,research about irrigation procedure, of old-gravel mulched field jujube trees. We analyzed the above observational data through chart comparision, difference analysis, regression analysis and other methods, explored water requirement rulers of jujube trees in main growth stages, and then we formulated practicable supplement irrigation procedure for jujube trees culvating. The main research results are as below.(1) In the whole growth stages, mean value of soil moisture content in water control area of CK, 30%θc,40%θc,5O%θc,60%θc treatment was 9.55%,12.16%,14.29%,15.80%, and 17.69% respectively. The variation of soil moisture content of each treatment was -2.04%,-1.48%,0.54%,3.69%, and 5.51% respectively. Variation of soil moisture in water control area of CK and 30%θc treatment were negative balance; it showed that in the condition of this growth pattern, plants had an adverse effect on field ecological rnvironment protecting and restoring.(2) In observation period, the cumulative growth of new slightly of CK,30%θc,40%θc,50%θc, 60%θc treatment was 19.01cm,20.74cm,22.78cm,23.81cm, and 25.60cm respectively. Stability leaf area of each treatment was 5.75cm2,6.90cm2,7.83cm2,7.93cm2, and 9.13cm 2 respectively. Canopy redundancy of each treatment was 1.18kg/tree,1.20kg/tree,2.03kg/tree,2.14kg/tree, and 2.38kg/tree respectively. Fruit setting rate of each treatment was 6.67%,5.65%,10.00%,14.29%, and 17.39% respectively. Yield of each treatment was 80.28 kg/666.7m2,179.87kg/666.7m2,231.30kg/666.7m2, 265.1 lkg/666.7m2, and 275.36kg/666.7m2 respectively. It showed that in this irrigation pattern, water stress condition has restricted development of canopy biomass and fruits greatly.(3) The mean value of water use efficiency of each treatment was 3.20mmol/mol,2.74mmol/mol, 2.92mmol/mol,2.81mmol/mol, and 2.48mmol/mol respectively. Water use efficiency of 40%θc and 50%θc treatment were high in daytime. In growth stages, the mean value of net photosynthetic rate of each treatment was 6.53μmolCO2m-2s-1,9.62μmolCO2m-2s-1,11.80μmolCO2m-2s-1,12.22μmolCO2m-2s-1, and 13.07μmolCO2m-2s-1 respectively. The net photosynthetic rate improved as irrigation increased.(4) Canopy biomass and net photosynthetic of 30%θc treatment were less than that of 60%θc treatmen by 49.6% and 26.4%, dropping lagerly. It showed this water stress condition was not suitable for jujube trees normally growthing. Canopy biomass and net photosynthetic of 40%θc treatment were less than that of 60%θc treatmen by 14.7% and 9.72%, dropping a little. In this water stress condition jujube trees could still growth normally.The soil moisture was 40%θc for old-gravel mulched jujube trees to healthily growth.(5) The results showed that irrigation moisture limit for old-gravel mulched field jujube trees cultivating was 50%θc in order to get higher yield and water production efficiency, with irrigation 4 times in the whole growth stage. In high flow year, the irrigation quota was 135.0m3/666.7m2,and the irrigation norm was 36.0m3/666.7m2、33.1m3/666.7m2、35.3m3/666.7m2, and 30.6m3/666.7m2 respectively. In normal flow year, the irrigation quota was 140.6m3/666.7m2,and the irrigation norm was 33.6m3/666.7m2、32.6m3/666.7m2、35.8m3/666.7m2, and 38.6m3/666.7m2 respectively. In low flow year, the irrigation quota was 143.5m3/666.7m2,and the irrigation norm was 36.9m3/666.7m2、 32.6m3/666.7m2、32.5m3/666.7m2, and 41.5m3/666.7m2 respectively.In conclusion, this essay has primarily analysised relationship between canopy biomass, photosynthetic process and soil moisture content, it also has put forward irrigation proceduce of old-gravel mulched field jujube trees in order to gain high yield and water production efficiency, providing foothold to formulate irrigation procedure for old-gravel mulched field jujube trees culvating in Ningxia. |
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