Study On The Effect Of Soil Water And Salt Distribution Characteristics And Winter Wheat Yield By Saline Water Border Irrigation

Rational utilization of saline water is one of the main paths to realize sustainalbe utilization of water and soil resource. On the basis of using for reference of saline water surface irrigation research findings both abroad and home, the paper took saline water border irrigation in Hebei province Cangzhou City Nanpi County for the case and adopted adjoint method of both indoor and field experiments, study the impact on saline water seepage characteristics, soil physicochemical properties as well as rational field irrigation procedure and others, it made conclusions as below:(1) On the basis of systematic analysis of saline water infiltration characteristic, study on feasibility of describe saline water infiltration characteristic by infiltration formulation which possess definite physical significance, it showed that both Green-Ampt Model and one-dimension Algebraic Model can relatively exactly describe saline water infiltration process, but deviation building up in company with mineralization degree uprising, parametric accuracy requirement of one-dimension Algebraic Model is higher than that of Green-Ampt Model.(2) When mineralization degree is 3 g/L, Sodium Adsorption Ratio has little effect on soil salinity, but Na+will be dominant cation in soil solution when sodium adsorption ratio is more than 8.18 (mmol/L)0.5, it will make part of exchangeable Ca2+and Mg2+was substituted by Na+, final result is soil evolute to solonetzic soil in subclass classification.(3) It made a conclusion that dry farming all existed in soil drought state after jointing period by three years fresh water irrigation tests, so it is necessary to carry out supplemental irrigation in irrigation district, it is 508.04mm to winter wheat optimal water consumption, corresponding maximum production is 6904.15 kg/hm2; when precipitation rate is 210mm the marginal utility is maximum both in commonly and humidity year within growing season, precipitation rate is 270mm has maximal marginal utility in relatively drought year.,(4) Through three years' saline water surface blending irrigation test results analyses, it showed that 3 g/L is relatively safety whether from soil water salinity distribution and crop yield, soil tend to alkalization when saline water mineralization degree is more than 4 g/L; rotational irrigation showed that optimal irrigation procedure is fresh (jointing water) fresh (tassel water) salty (grouting water) when growing season came into use once salty twice fresh water, optimal irrigation procedure is salty (jointing water) fresh (tassel water) salty (grouting water) when twice salty once fresh water was used.(5) Soil water potential descended by saline water stress irrigation and soil pore is full of air, it makes the tortuosity of nutrient diffuse path increased, and impact the crop yield. Soil moisture obtain high efficiency utilization in company with the backward shift of water shortage stage, and plant height, leaf area index and yield water stress have hysteresis effect by water stress, therefore stress stage should postposition.(6) Both moisture content and salt content has a smaller dispersion alonge the border head to border tail by saline water surge flow irrigation, yield decreased significantly irrigated by saline water traditional surface border irrigation than that of surge flow irrigation. Both irrigation efficiency and irrigation uniformity were analyzed by SRFR Model, it showed that when the field slope gradient is 0.15%, border length is 200-250m, unit width flux is 3.0～4.0L/m.s, periodic numbers is 3, circulation rate is 1/3, water supply time in one period is 30 min, surge flow irrigation can obtain maximal irrigation degree.