Research On Effects Of Irrigation Water Spatial Distribution On Spatial And Temporal Variability Soil Water-nitrogen In Potato Fields

The local water resources in Yulin City are in short supply.As one of the five major potato production areas in the country,traditional methods of irrigation and fertilization are still used,making water and fertilizer fertilizer resources wasted,and production efficiency is low.The introduction of precision agriculture can effectively alleviate this problem.It is important to master the spatial variability of various indicators of potato field and its influencing factors theoretically,and to the development of local potato precision agriculture.The study was conducted at a potato planting base in the Maowusu Desert.The area of the study area was 38.7 hectares and 116 sampling sites were deployed.Soil moisture content,nitrate nitrogen,ammonium nitrogen,soil particle composition,water.above and below canopy,and potato leaf area index were collected for 2016 and 2017.The characteristics of spatio-temporal variability of soil water and nitrogen in potato growth period were analyzed using classical statistics and geostatistics.The effects of soil particle composition distribution and sprinkler uniformity in the distribution of nitrogen in the field were investigated.Get the following main results:(1)The canopy divides the amount of sprinkling irrigation water into three parts,in which the penetration water accounts for a large proportion of the total water,and the proportion of each growth period exceeds 50%.The growth trend of the potato decreases first and then increases,and the stem flow rate and crown The trend of change in layer interception is opposite.In the single potato canopy coverage area,the effective uniformity coefficient of sprinkler irrigationwas between 16.45%and 29.87%,and the canopy had a "negative optimization" effect on water redistribution within the coverage of individual potato canopy.(2)The soil moisture content during the growth period of potato showed moderate content,and showed an exponential function.The soil moisture content showed moderate spatial correlation.The soil moisture content varied significantly with potato growth,and the spatial structure of the soil moisture content in the two years was different.(3)During the growth period of potato,the soil nitrate nitrogen showed moderate variability,and the variation degree of ammonium nitrogen was between weak and moderate variation.The spatial variability of soil nitrate N is mainly caused by random factors,and the spatial variability of ammonium N is mainly caused by structural factors.(4)Irrigation uniformity has little effect on the spatial distribution of soil water and nitrogen.There is a clear correlation between soil particle composition and soil moisture content.The sand grains showed a negative correlation,and the clay particles and powder particles were positively correlated.The correlation between soil particle composition and nitrate nitrogen was not obvious.The uniformity of the distribution of soil particle composition during potato tuber formation to starch accumulation had a certain influence on the spatial distribution of ammonium nitrogen.