Study On Mechanism And Regulation Of Soil Water-Salt-Nutrient Movement Under Drip Irrigation Of Grape In Saline Land

Xinjiang,which accounts for one sixth of China's territory area,is a strategic barrier and an important reserve area of resources in Northwest China.It is of great significance to safeguard China's sustainable development capacity and its strategic position is very important.Xinjiang is a typical inland arid area,where water resources are scarce,soil fertility is low and saline-alkali land is widely distributed,which is the main restrictive factor for local agricultural development.Water saving and saline alkali land control and improvement are necessary ways to promote agricultural development in Xinjiang.Xinjiang is the main grape producing area and high-quality producing area in China.The planting area and output account for more than 50%of the whole country.It is an important pillar of the agricultural and forestry economy.Grape irrigation in Xinjiang mainly uses flooding irrigation and furrow irrigation.Water resources are wasted seriously,soil salinization is aggravated,fertilizer efficiency is low,grape yield and qualities are not high.Every year,due to water shortage and salinity problems,grape yield is reduced and losses are huge.Drip irrigation technology has significant water saving effect,and can also be fertilized with water to achieve the integration of water and fertilizer.However,unreasonable irrigation system and water and fertilizer management mode will lead to soil salinization and fertilizer utilization rate reduction,resulting in waste of resources and environmental problems.It is of great theoretical significance and practical value to study the law of water and salt transport and the coupling effect of water and fertilizer in Xinjiang arid area.In order to improve the utilization ratio of water resources and fertilizers and control soil salinization in arid areas of Xinjiang,this paper selected Frey,a representative fresh grape variety,as the research object in the 6th company of 147 regiment of the 8th Division of Xinjiang Production and Construction Corps from 2016 to 2017,and set up a field plot based on the interaction of water and fertilizer of drip irrigation grapes in saline-alkali land.The experiment aimed to provide scientific basis for the scientific and rational management of grape production and the improvement of quality and efficiency through the coordinated regulation of water,fertilizer and salt.The main conclusions are as follows:?1?Ditching width is the main factor affecting soil irrigation uniformity.Among the different ditching patterns and irrigation combinations.When the irrigation quota is 40m³/667m² and the width of the ditch is 80cm,the uniformity of irrigation is the highest,which can reach 86%.?2?Drip irrigation combined with film mulching can greatly improve the surface soil moisture content.Under the effect of irrigation and repeated evaporation,condensation and infiltration microcirculation of soil moisture in film mulching,the salt in soil moves to the lower part of soil,and the salt migration in soil layer near the dripper is more obvious.When the irrigation quota is 40m³/667m²,the depth of salt migration can reach 60⁸0cm.However,in the bare area,there is a significant surface accumulation of soil salinity,which is the result of the soil salinity in the deep layer moving upward with the evaporation of water and re-depositing on the surface of the soil.?3?HYDRUS software can more accurately simulate the dynamic changes of soil water and salt during grape growing period,which can provide a quantitative discriminant model for actual production activities.?4?The values of root growth dynamic indexes increased from flowering and fruit setting stage to harvesting stage under different irrigation amount and ditching mode.Irrigation water amount had a great influence on root growth dynamic index values.Total root length,total projection area,total specific surface area and total volume were positively correlated with irrigation amount,while root average diameter was negatively correlated with irrigation amount.Among the two factors affecting root growth,irrigation water plays a leading role in root growth.?5?Using ¹⁵N tracer method to analyze the distribution of ¹⁵N in soil and the characteristics of nitrogen uptake and utilization of grape,it was found that the total nitrogen content and ¹⁵N abundance gradually decreased with the increase of soil depth in the range of0-100 cm.The contribution rate of ¹⁵N fertilizer increased with the increase of fertilizer application rate,and the utilization rate of fertilizer increased with the reasonable water-fertilizer ratio..?6?At different growth stages and the same irrigation amount,with the increase of fertilization,the photosynthetic index increased and decreased.Under the same amount of fertilizer,with the increase of irrigation water,photosynthesis index increased gradually in different grape growth stages,and photosynthesis noon break phenomenon was obvious in the experiment.The grape yield was the highest when irrigation quota was 360 m³/667m² and fertilizer application was 100 kg/667m².The photosynthetic rate of grape was the highest when irrigation quota was 360 m³/667m² and fertilizer application was 120 kg/667m².The photosynthetic rate was correlated with yield,but not completely consistent.The innovations of this paper include the following 2 aspects:1.Quantify the effect of water and fertilizer combination mode on grape production and the contribution of different nitrogen sources to its growth.2.Quantify the effects of ditch width,drip irrigation combined with film mulching on water use and soil salt control in grape production.