Regulated Deficit Irrigation Schedule And Water Fertilizer Coupling About Mountain Jujube Of Surge-Root Irrigation On Northern Shaanxi

The condition of the Loess Plateau is special: the seriousness of the water and soil erosion and the fragile ecological environment. Regulated deficit irrigation and water fertilizer coupling have a greater impact about the growth and yield of jujube. In order to ensure the economic benefits of ecological economic forest, achieve the sustainable use of the limited water resources in Northern Shaanxi area, improve the water use efficiency, so, this paper made some experiments about regulated deficit irrigation and water fertilizer coupling under surge-root irrigation in the jujube water test base in Northern Shaanxi area to study the mountain jujube from 2016 April to October. According to the effects of soil moisture, water consumption,ecological index, yield and water-fertilizer use efficiency from different experiments, analyzed the coupling effect of water and fertilizer and established the regulated deficit irrigation system about jujube in Northern Shaanxi Province in high flow year. The main results as follows:(1) Soil moisture content of 0-80cm deep increased obviously and 80-100cm deep had a little change after irrigation. The effect of soil moisture content is time limited during the whole growth period of jujube. The time limited is influenced by irrigation and less than 15 days.Water consumption in the whole growth stage of jujube is the sum of the rainfall and irrigation amount, so the differences of different experiments about jujube's water consumption mainly lead by irrigation.(2) There is extremely significant parabolic function relationship between the growth of jujube's branches and time, the error between the analog value and the measured value less than 10%, so the simulation result is good. The function model is apply to the time quantum between the begaining of jujube's growth stage and the maximum of function simulation. The irrigation of jujube's flowering-fruiting stage could promote the growth of branches and leaves of jujube,improve the fruit setting rate. The irrigation of jujube's fruit enlargement growth stage could promote the growth of jujube fruit. The volume of jujube fruit increased 68% than non-irrigation and 8.8% than full irrigation. The improvement of regulated deficit irrigation is poor for water use efficiency, but significant for irrigation water use efficiency. The irrigation water use efficiency of regulated deficit irrigation increased 57.8% than full irrigation. Fruit enlargement growth stage and flowering-fruiting stage are the water-sensitivity of jujube.(3 )Fertilize in flowering-fruiting stage can significantly encourage the growth of jujube's branches and leaves, improve the fruit setting rate. Fertilize in fruit enlargement growth stage can promote the growth of jujube fruit and increase the yield. Spraying fertilizer in flowering phase can significantly improve the fruit setting rate, system: the concentration of boric acid solution is 0.2%, the weight is about 200g per tree, ten-day is a cycle and three times one growth stage. Water and fertilizer coupling for jujube could significantly mutual promotion,improved water and fertilizer use efficiency distinctly.(4) Suggestion for water-fertilizer coupling under regulated deficit irrigation: the flowering-fruiting stage implement regulated deficit irrigation and additional fertilizer is about 15% of the fertilization amount of whole year; the fruit enlargement growth stage should ensure irrigation and additional fertilizer is about 25% of the fertilization amount of whole year. The irrigation system apply to jujube in the north of Shaanxi Province in high flow year, irrigated once time in flowering-fruiting stage with slight regulated deficit irrigation, then irrigated twice time in fruit enlargement growth stage, and the first one was full irrigation and the second one was slight regulated deficit irrigation.