Research On Soil Water And Nitrogen Distribution Character And Use Efficiency Under Film Drip Irrigation In Spring Maize

To explore the high-yield and high-efficiency combination of water and nitrogen combination of spring maize in the Hexi region,Xianyu 335 was used as the carrier,field experiments were conducted on the irrigation and nitrogen application levels.Irrigation levels:95%FC,80%FC,and 65%FC?FC is the soil water holding capacity of the field?,denoted as FI,DI1,and DI2,respectively.Nitrogen application levels:0,70,140,and 210 kg/hm²,recorded as N0,N70,N140,and N210,respectively.That affect the spring maize's growth,biomass,yield,nitrogen accumulation,soil water content and nitrate nitrogen content and their distribution,water and nitrogen utilization efficiency and economic benefits,to provide a theoretical basis for the selection of reasonable irrigation and fertilization levels for spring maize to save water and fertilizer and increase yield in the west of Gansu Province.The following main results are obtained:?1?The effects of different irrigation and nitrogen application levels on plant height,stem diameter and leaf area of spring maize were compared.It was found that the plant height,stem diameter and leaf area index of spring maize increased with the increase of irrigation and nitrogen application.The response of plant height to nitrogen application level was different under different irrigation levels.The plant height of DI1and DI2 treatments increased significantly with the increase of nitrogen application level,while the plant height of four nitrogen application treatments under FI irrigation level had no significant difference;the effect of different irrigation and nitrogen application levels on stem diameter was significant.With the improvement of irrigation and nitrogen application level,leaf area index increased,but the growth rate gradually decreased;on the 98th day after sowing,leaf area index of spring maize treatment reached the maximum,and that of FI×N210 treatment was the maximum,it is8.42m²·m^-2.?2?The effects of different irrigation and nitrogen application levels on dry matter accumulation,nitrogen accumulation,grain yield,water use efficiency and nitrogen partial productivity of spring maize were studied.The above ground dry matter quality,nitrogen accumulation and grain yield increased first and then decreased with the increase of irrigation level.The above ground dry matter accumulation,nitrogen accumulation and grain yield of DI1 treatment were significantly higher than that of DI2 and FI treatment.In a certain range,the dry matter accumulation,nitrogen accumulation and grain yield increased with the increase of nitrogen application level.In a certain range,increasing nitrogen application is beneficial to increase water use efficiency of spring maize,but if nitrogen application is more than 70kg/hm²,water use efficiency will be reduced;increasing nitrogen application will lead to a significant reduction of nitrogen partial productivity.?3?The effects of different irrigation and nitrogen application levels on soil water content and nitrate nitrogen content were analyzed.In a certain range,the soil water content increased significantly with the increase of irrigation level;in different growth stages,the effect of Nitrogen Application on soil water content was different,which showed that from jointing stage to grouting stage,the soil water content decreased with the increase of nitrogen application level;in mature stage,the soil water content increased first and then decreased with the increase of nitrogen application level,and the maximum value was obtained under N140 treatment.The content of nitrate-N in the soil profile decreased with the increase of soil depth,and the distribution difference of nitrate-N in the surface soil was significantly larger than that in the lower soil;under the same irrigation level,the higher the level of nitrogen application,the higher the content of nitrate-N in the soil;when the irrigation level was lower,the content of nitrate-N in the soil was difficult to be absorbed by the crop roots.?4?A suitable combination of water supply and nitrogen supply in Hexi region is proposed based on yield,economic benefit and water nitrogen utilization efficiency.The net benefit under DI1×N140 treatment is the largest,and the net benefit is 25390yuan/hm²;the which is 4.39kg/m³.Therefore,the most suitable combination of irrigation and nitrogen level for spring maize in Hexi region of China is DI1×N140,the seed yield reaches 23.68 t/hm²,and the net benefit is 25390 yuan/hm².