Research On Imgation System And Fertilizer Application Technology Of Integrated Water And Fertilizer For Mountainous Apple Trees In The Northern Shanxi

In this study,through a combination of field test and indoor simulation test,the potential evapotranspiration(ETc)of the fruit trees was calculated according to Penman-Monteith by measuring the soil moisture content and the growth condition of the apple tree in the test area.Then combining the long series of rainfall collected through the Yan’an Meteorological Bureau,the irrigation system of the apple trees under different tree age in the Northern Shaanxi mountainous region was studied,and the effects of different phosphorus and potassium fertilizers and different water-soluble phosphate fertilizers on the soil nutrient migration were explored under the simulated drip irrigation conditions.The following 4 conclusions are drawn in this study.(1)dwarfing apple trees have shallow roots,and soil moisture supply has great influence on the growth of fruit trees.The rainfall in Yanan in the Loess Hilly and gully region of Northern Shaanxi is 485.6 mm in 2017.For the young tree of the dwarf apple in the mountain area,although the annual rainfall is rich in the water demand for young fruit trees,the rainfall is mainly concentrated in the month of 7-10 due to the uneven distribution of rainfall,which is 68% of the annual rainfall,and before July.The germination period and the rapid growth period of the fruit tree were less than 155.8 mm,less than 169 mm of transpiration in the same period,which resulted in the slow growth of the apple tree,the smaller the tree shape,the 75% and 70% of the tree height and leaf area index,respectively,and the average number of effective branches of the average single fruit tree above 50 cm,respectively,were less than 15.In the late stage of apple production,only supplementary irrigation can ensure the healthy growth of fruit trees.(2)The irrigation quota for young trees in wet year,general year and drought year were 38,31 and 41 mm respectively.The primary fruit trees and fruit trees were mainly irrigated before fruit tree germination(March),post fruit(May and June)and deciduous period(November),and the irrigation quota of early fruit trees in wet year,general year and drought year was 57,46 and 62 mm respectively,the irrigation quota of fruit trees in wet year,general year and dry year is 66,53 and 66 mm respectively.(3)when the soluble phosphorus and potassium fertilizer are applied to the soil as the base fertilizer,they were both migrated with the infiltration of drip irrigation.The high value area of the available phosphorus was appeard near the edge of the moist area,and the available potassium was more evenly distributed in the moist area;with the water phosphate fertilizer,the depth was only in the wetting area 20 cm,and the water square is square.The soil layer within 15 cm is accumulated.When the amount of phosphate fertilizer was unanimous,the maximum value of available P in the soil was significantly higher than that of the base fertilizer.The distribution of available K in the soil tended to be homogeneous with the application of potash fertilizer with water,but the high value area was formed near the drip point,and the potassium fertilizer could slow down the available potassium to a certain extent.(4)the effect of two treatments on the migration of insoluble superphosphate in soil was not obvious.The migration range was near the point source,and the migration range was increased with the water application to a certain extent.As the base fertilizer was applied,the migration range of ammonium phosphate two was basically consistent with the law of water migration.The shallow phosphate fertilizer will migrate to the deep soil mass with the impetus of water migration.With the increase of irrigation water,it may cause the leaching loss of phosphate fertilizer.Under the test conditions,the application of two ammonium hydrogen phosphate can only be applied.In the soil layers with radial 15 cm and depth 20 cm,migration was more obvious(which is basically consistent with the migration results of water superphosphate),the soil available phosphorus in the rest of the soil was basically stable.However,under the same fertilizer application conditions,the spatial and temporal distribution of phosphate fertilizer in the soil wetting area was significantly different with the application of water and fertilizer integrated irrigation.The high value area of phosphorus content in soil was distributed near the drip point,and the content of available phosphorus in the moist area far away from the drip point was relatively low.