Study On Deficit Irrigation Schedule And Irrigator Arrangement Of Apple Trees By Bubble-root Irrigation In Hilly-gullied Areas Of Northern Shaanxi

This paper takes the 6-year-old apple trcc in the hilly and gully area of northerm Shaanxi as the research object,experimenls on the rcgulated deficit irrigation of apple trees and the arrangement of emitters under the conditions of bubble-root irrigation were carried out.Different degrees of water-rcgulacd irrigation were carried out in different growth stages of apple trcees,monitored soil water content and combined with meteorological data to explore the effects of regulated deficit irrigation on apple trees of water consumption,physiological characteristics,fruit yield and quality.A regulatecd deficit irrigation scheduling of apple trees in the northern Shaanxi province was established.The effects of diffcrent depths,spacings and numbers of irrigation emitters on the physiological growth and yield of apple trees were studied,and the optimal arrangement of bubble-irrigation irrigators of the app le tree in the mountainous areas of northern Shaanxi was obtained.The main research results arc as follows:(1)After irrigation with the bubble-root irrigation technology,the water content of 0-90cm soil layer changed significantly.With the incerease of water deficit,the soil moisture content of the same soil layer gradually decreases,and the vertical profile of soil moisture shows a trend of high middle and low ends.0-30cm soil layer evaporates faster,soil moisture content is lower,and soil moisture is the highest in 40-90cm soil layer.the soil moisture content in the100-140cm soil layer is low and the difference is small.The coefficent of variation,of soil moisture content in 0-90 cm was negatively correlated with the degree of water deficit,while the coefficient of variation fo 100-140cm soil moisture content was positively correlated with the degree of water defieit.(2)Duing the whole growth period of the applc tree,the flictuation of the dayevapotranspiration of the reference crop was larger?and shows a trend of high middle and low ends.ETO was significantly positively correlated with sunshinehours and daily average temperature;it was not significantly correlated with water vapor pressure and wind speed at 2 m;it was negatively correlated with atmospheric pressure;it is a quadratic function relationship with relative humidity.The water consumption of the regulated deficit irrigation treatment during the whole growth period is 420.98?719.64mm.The water consumption of each treatment of the bubble-root irrigation emitter layout test is small,and the water consumption is 586.77?641.42mm.The order of water consumption of apple trees under the test of the irrigator arrangement and the regulated deficit irrigation of the bubble-root irrigation are consistent and both:fruit swell period>sprout leaves period>flowering fruit setting stage>fruit ripening stage.(3)Spring shoot length,leaf area,venetian weight,leaf water retention,leaf water content,single fruit weight,soil water content were positively correlated with apple volume and fruit water content,the coloring degree,organic acid,vitamin C and soluble reducing sugar were not significantly related to soil moisture content,and the fruit hardness and soluble solid content increased with the degree of deregulation.The fruit expansion period is the key period of fruit water demand,and the water deficit in this period leads to a significant decrease in yield.The apple leaf area index showed an "S"-shaped curve growth,and the yield was quadratic with the water consumption during the whole growth period.The net benefit of T6 treatment(sprout leaves period moderate deficit,fruit swell period slightly deficit)in the deficit irrigation experiment was 309,800 yuan/ha.The net benefit of T9 treatment(buried depth 40cm,30cm from the trunk,symmetrically arranged two emitters)in the experiment of emitter placement is up to 221,000 yuan/ha.(4)The high-efficiency water-saving irrigation scheduling of mountain apple trees under the conditions of bubble-root irrigation in the hilly and gully region of northern Shaanxi is:moderately regulated in sprout leaves period,irrigation once;full irrigation during flowering frmit setting stage,irrigation 1 time;fruit swell period slightly deficit,irrigation 3 times;not watering in fruit ripening stage,the irrigation quota is 870.39 m3/hm2.The optimal arrangement of the bubble-root irrigator is:the emitter is 40 cm away from the surface,30 cm from the main trunk and two emitters are arranged symmetrically in both directions.The results of this study can provide a scientific basis for the water management of apple trees in the hilly and gully regions of northern Shaanxi.