Response Mechanism Of Water And Fertilizer Coupling Effect And Simulation Under Salt Stress In Hetao Irrigation

China's economic development is based on agriculture while the water resources is quite scarces. Water saving , salinization control and utilization in agticulture is mentioned to high position . Development and utilization of the lower fertility land especially the salinization has become one of the important ways to solve population demand for food and agricultural sustainable development. In western China ,the HeTao irrigation area belongs to drought,cold and desert region also with less rainfall.The inter-regional,inter-annual and inter-seasonal distribution is uneven and its variation changes great.The soil evaporation is strong and the shortage of water resource increases day by day.There exsites serious potential theate to secondary salinization when soil parent material contains salt and groundwater level is higher. Soil is an important carrier of agticulture survival and development.Water and fertilizer are the two key factors to the agriculture development and the improvement of agriculture efficiency.Nodays,many domestic and foreign scholars have carried out extensive fruitful studies on coupling of water and fertilizer whears they are mainly focus on the area which is not salinization.Especially in water-saving conditions,crop grow in salt stress environment then the coupling of water and fertilizer mechanism becomes more complicated. Therefore, study on mechanism of salinization coupling of water and fertilizer , the key problem to be solved urgently in northwest salinization region was to made the water- fertilizer - salt coupling management mode which under the condition of saving water,This paper choose the main economic crops-oil sunflower of Hetao irrigation as the study target,using the pot esperiment in combinition with the field test method , appling pedology,water conservancy, plant physiology, agricultural and meteorological etc multi-subject theory and so making research on oil-sunflower copling of water and fertilizer which under the condition of salt stess.1.Though analyzing the pot and field experient meterials,it quantitatively describe the influence regularity about the height, stem diameter, photosynthetic rate, transpiration rate, stomatal conductance, leaf RWC etc physiological and ecological factors , biomass and yield of sunflower which in different water,fertilizer and salt conditions.It presented the water-fertilizer management thresholds and index system which adapting to different level of salinization . 2. With Jensen model and BP artificial neural network model based. finally set up the water-fertilizer-salt production model that suite for different saline soil of oil-sunflwer.This paper reveals dynamic change regulation of water-salt and NO3-N beyond different water-fertilizer treatment.It also disscusses the different growth period variation of nitrogen distribution and accumulation of sunflower's each organ which under the condition of different saline soil and different water-fertilizer process.3. RZWQM model can better simulate treatment various soil moisture content, NO3 - N, biomass ect index Under different waterPot experiment research results show that sunflower seedling influence factors orde:salty>water > nitrogen, now bolls ~ flowering :water > salty > nitrogen.EC value 0.2 ~ 1.0 ms/cm containing salt on soil moisture in the soil was about 70%θfc, N 337.5 kg / hm2 or so best, and may slow the intimidation of sunflower salty. Soil EC value 0.1 ~ 0.45 ms/cm, Between salt water and fertilizer, shows certain linear relationship, Beyond the scope of nonlinear relationships showed。Comparative test showed that the optimum amount of fertilizer (N 225kg/hm2, P 150kg/hm2) can ease the stress of water and salt, the orders of the effect were"water> P> N"in light and"water> N> P"in moderate. There was positive effect in the interactions of water, nitrogen and water. The orders of effect were"nitrogen and phosphorus> phosphorus and water> nitrogen and water"in light and"nitrogen and phosphorus> nitrogen and water> phosphorus and water"in moderate. The optimize applications of fertilizer and water were N 225 kg/hm2, P 150 kg/hm2 and water 1088m3/hm2.Salt water and fertilizer production model has certain value in guiding agricultural production, RZWQM model can be applied to simulate the Sunflower.The results of research reveal the theory of solinization coupling of water and fertilizer preliminarily.It also provide theoretical scientific basis for sustainable development of irrigation areas,raising the farmland utilizing fficiency and developing the salinization agricultural production.