Effects Of Fertilization On Characteristics Of Water And Nitrogen Transport And Winter Whent Under Muddy Water Hole Irrigation

Due to water resources are relatively scarce,the development of new and efficient water-saving irrigation technologies is the development trend of farmland irrigation technologies.This paper combines the characteristics of the Yellow River muddy water irrigation,based on the new technology of film hole irrigation,through the soil box test,analyzed the characteristics of soil water and nitrogen transport under different fertilization methods and fertilization conditions,and the effects of nutrients on plant growth characteristics were studied through a pot experiment of planting winter wheat.The main achievements are:(1)Based on the problem of sediment contained in muddy water,the layered soil was taken as the object to study the influence of different sediment rates on the infiltration characteristics of the layered soil,and the relationship between the sediment rate and the cumulative infiltration volume and the migration distance of the wet front was established.The results show that muddy water sand content has the effect of reducing infiltration.At the same time,the cumulative infiltration volume,the moving distance of the moist front and the soil moisture content at the same location decrease with the increase of muddy water and sand content,After the infiltration,compared with the infiltration of clean water,the sand content rate is 2%,5%,7%,9%,respectively.The permeability reduction rate is 31.53%,47.30%,54.12% and 60.95%.(2)The effects of different fertilization manners on film irrigation of muddy water were studied,and the characteristics of muddy water infiltration,water migration and nitrogen migration and transformation under the influence of each fertilization method were investigated,and the cumulative infiltration volume of different fertilization manners was established.The relationship between the moving distance of the wet front and the infiltration time.The results show that: after the water supply is completed,the surface application mode corresponds to the cumulative infiltration volume,the maximum wet front migration distance,the highest moisture content in the same location of the soil,and the larger the range of the wetted body;The inorganic nitrogen after hydrolytic conversion of surface application and deep application of urea is mainly concentrated in the vertical 7.5cm below the surface,while the irrigation method has the largest content of ammonium nitrogen after urea hydrolysis near the center of the membrane hole.Without fertilization,the hydrolysis rate and nitrification rate of urea are different.Among them,the hydrolysis rate is the fastest under surface application conditions,and the soil ammonium nitrogen conversion is faster.After the irrigation is completed,the hydrolysis is basically complete on the 4th day,complete conversion of soil inorganic nitrogen on day 12 of redistribution,followed by irrigation,and the complete hydrolysis and transformation took 5 and 14 days,respectively,and the deepest application conditions were the slowest.(3)The effect of different concentrations of urea fertilizer solution on the infiltration characteristics of muddy water film pore irrigation was studied.The process of varying concentrations of muddy water infiltration volume and wetting front with time was analyzed.A power function correlation was established,and the different urea concentrations on the soil were analyzed.The effects of moisture content and nitrogen content of the wetted body showed that the concentration of fertilizer solution promoted the infiltration rate,and the cumulative infiltration amount per unit membrane pore area during the same infiltration time increased with the increase of urea concentration.In the Kostiakov infiltration model,the greater the concentration,the greater the rate of infiltration;different urea concentrations at the same infiltration time correspond to the migration distance of the wet front.The greater the soil moisture content at the same location.The above shows that the greater the concentration of urea fertilizer solution,the greater the probability of combining with soil colloids to form aggregates.Increasing the soil pores accelerates the infiltration rate,the water migration channel is smoother,and the wetting front advances faster.The water migration channel is smoother,and the moistening front advances faster.Compared with clear water infiltration,the concentration of fertilizer solution was 352 mg/l,763 mg/l,and 1174 mg/l,respectively,which increased infiltration by 19.9%,36.3%,and 52.6%.Moisture front migration distance and soil water content increase with the increase of fertilizer concentration.Fertilizer infiltration significantly increases the soil nitrogen content,the greater the content of urea molecules in the soil,the greater the content of ammonium nitrogen in the soil after hydrolysis,and the increased nitrification reflectance caused the conversion The greater the soil nitrate nitrogen content.(4)Based on the effect of indoor fertilization on the infiltration characteristics of muddy water film holes,an outdoor winter wheat pot experiment was conducted to analyze the growth index and dry matter accumulation and distribution of winter wheat with different fertilization in different growth periods.The effects of yield formation and nitrogen absorption and utilization,through analysis of variance,showed that the nitrogen application amount and nitrogen application period had significant effects on the above indicators.Nitrogen application in the greening-joining stage can effectively promote winter wheat plant height,photosynthetic rate,dry matter accumulation during flowering and mature stages,yield and nitrogen absorption and utilization rate,and effectively reduce soil inorganic nitrogen residues and apparent nitrogen losses during mature stage,compared with the jointing-heading stage and the heading-grouting stage,the yield growth rate of nitrogen application in the greening-joint stage was 31.6% and 72.2% respectively;The higher the amount of nitrogen applied during the same growth period,the higher the winter wheat plant height,photosynthetic characteristics,dry matter and yield accumulation,and plant nitrogen accumulation,but it will increase the soil inorganic nitrogen residual and nitrogen uptake and utilization efficiency during maturity.Fertilizer application at 240 kg/hm2 in the greening-joining stage corresponds to the maximum grain yield in the mature stage.