A Kind Of Sand Land Development And Utilization Technology Study Based On Water-retaining Reagent And Drip Irrigation

China is a big agricultural country,and there is a serious shortage of water resources.At the same time,the efficiency of irrigation water is not high,and the waste of agricultural water resources and pollution problems are becoming increasingly prominent.With the development of economy and society and population growth,the demand for agricultural products has increased,the cultivated land has decreased relatively,and the comprehensive production capacity of land has been improved."Tibet and land for grain and technology for harvesting grain"has become a national strategy.China has a large area of sand and soil,and the problem of soil desertification is serious.Therefore,exploring new technologies to improve sand land,improving the ability of sand land to retain water and retain fertilizer,and scientifically utilizing sand resources are important for promoting the efficient development of agriculture and ecological security in sandy soil areas,meanwhile some extent also the need to ensure national food security.This paper discusses the influence of the water retaining agent on sandy soil retention capacity of fertilizer and crop growth by drip irrigation in experimental study,determines the technical parameters such as the optimal thickness and concentration of the water retaining agent for soil modification,which can provide the basis for holding agent on sandy rational exploitation of resources based.The main research contents and conclusions of this paper are as follows:(1)Through experiments to study the effect of different mass fractions of water retention agent on soil saturated hydraulic conductivity,it was found that:When the mass fraction of the water-retaining reagent is small,the saturated hydraulic conductivity of the soil decreases,when the mass fraction reaches 1%,the saturated hydraulic conductivity of the soil is almost 0 cm/d,and when the mass percentage of the water-retaining reagent reaches 100%,the saturated hydraulic conductivity reaches 196.1 cm/d.This shows that the water-retaining reagent not only swells,changes the soil voids,prevents moisture from passing through,also has a highly hydrophobic.Based on this test to block the bottom water leakage as the main goal,considering the cost,1%is the best quality fraction of the water-retaining reagent.(2)The effects of 1%water-retaining reagent-soil mixture on water distribution and migration were studied by small soil column test with a diameter of 3 cm.The results showed that:On the first day after the completion of the irrigation,the control of the water-retaining reagent was not applied,the wetting front quickly reached 21 cm,and the wetting front reached 28 cm(3)after 5 days of irrigation.Several sets of treatments were applied to fill the water-retaining reagent,the upper layer was completely saturated,and the wetted front reached 25 cm due to the large suction of the lower layer water,two treatments of 0.3 cm and 0.6 cm thickness;three treatments of 0.9cm,1.2cm and 1.5cm thickness,the wetting front is within 15cm depth,and the excess moisture can be better controlled above and below the water-retaining reagent layer.Therefore,in order to control the cost and achieve better results,1.0 cm is selected as the thickness of the water-retaining reagent.(4)The effect of 1%water-retaining reagent-soil mixture on the distribution and migration of nitrate nitrogen in different thicknesses was studied by a nitrate-nitrogen leaching column test with a diameter of 18 cm.The results showed that:Most of the nitrate nitrogen is concentrated in the water-retaining reagent layer and the surface layer,the maximum concentration of the water-retaining reagent layer reaches 84.9 mg/kg,and the maximum concentration of the surface layer reaches 60.3 mg/kg;without the treatment of 1%water-retaining reagent and soil mixture,nitrate nitrogen accumulated in the wet front of 5-10cm from the bottom,and the maximum concentration reached 36.9 mg/kg.The treatment of 1%water-retaining reagent and soil mixture is applied,and the nitrate-containing nitrogen in the water-retaining reagent layer and the above soil column accounts for 87.2%of the total,effectively preventing the infiltration of nitrate nitrogen and preventing loss.(4)Through artificial climate chamber cultivation experiment,it was found that under drip irrigation conditions,the water-retaining reagent promoted the growth and development of cucumber plants,increased the soluble sugar content of the leaves,increased the yield of cucumber,increased the sweetness and vitamin C content of cucumber,and enhanced the root activity.At the same time,the optimal irrigation system was established:the irrigation amount in the seedling stage was 0.2-0.8times of the evaporation amount;the irrigation amount in the flowering stage was 1.0-2.0times of the evaporation amount.