Optimization Study On The Monitoring Sites Of Orchard Soil’ Moisture And Nutrient Under The Water Storage Pit Irrigation

Soil moisture and nitrogen are important factors affecting of crop growth,the content of moisture and nitrogen in soil effect the growth and the yield of the crop.For this reason,it is extremely important to measure the content of soil moisture and nitrogen accurately and timely.A lot of studies have shown that the content of soil water and nitrogen are not present a simple one-dimensional layered homogeneous distribution characteristics under the condition of water storage pit irrigation,and moisture content are affected by many factors easily,such as rainfall and irrigation.Therefore,it is inevitable that lay out dense monitoring stations in the soil around the fruit tree in order to measure the content of the soil moisture and nitrogen accurately.However,this method is not only increasing the workload of measurement,but also increasing the cost of the soil moisture sensors and the nitrogen sample acquisition device in soil.Therefore,the studies are extremely urgent that how to reduce the amount of moisturenitrogen station layout on the premise that control the soil moisture content,nitrogen content information accurately.At present,the research and exploration of soil moisture sensors position focus on field crops primarily with drip irrigation,the optimization study that how to distribute the moisture measuring probe around fruit trees under thecondition of water storage pit irrigation is relatively few,and the research on soil nitrogen sampling point layout is hardly any.This experiment as the background,using the mathematical statistics method,such as correlation analysis,cluster analysis,principal component analysis and factor analysis,and on the premise of considering the rainfall and irrigation effect factor on the content of soil moisture and nitrogen,trying to find a representative monitoring position,studying the volumetric moisture content,nitrogen content and the conversion relationship between the soil profile moisture content and nitrogen content around the fruit trees.Finally,verify the transformation model accuracy validation using the measured data,draw the following conclusions:(1)Under the Water Storage Pit Irrigation,there are obvious correlation between the volumetric water content of the monitoring point which does not across the pit and of fruit trees 30 cm distance(b30)and the average volumetric water content of the whole fruit tree and linear formula can be used to show the relationship between them.Meantime,use the measured data to verify,the result also indicate the linear formula which is established has high prediction accuracy.Therefore,we can use the volumetric water content of the monitoring point of b30 to estimate fruit trees’ surrounding soil moisture conditions under the Water Storage Pit Irrigation.(2)Under the Water Storage Pit Irrigation,the content of ammonium nitrogen has a certain correlation between different soil depths,and among the vast majority of soil layers,ammonium content reaches significant relevance atthe 0.01 level(on both sides),this suggestes that there is a good correlation between them.Through Mathematical Statistics-Cluster analysis,we draw the following conclusion:Under the Water Storage Pit Irrigation,we only need to lay three sampling points on 0~20cm、20~ 40 cm and 100~120cm soil layers and each soil-layer lays five points ——which does not across the pit and of fruit trees 30 cm distance( b30), which acrosses the pit and of fruit trees 30 cm distance(g30)、50cm distance(g50)、120cm distance(g120)and which between acrosses the pit and does not across the pit and of fruit trees 75 cm distance(z75)to effectively monitor the content of soil-ammonium nitrogen below the surface within the depth of 0~200cm around fruit trees.Further use of measured data to validate the conclusions of the test,the results show that it has a high prediction accuracy,reliability is better.(3)Under the Water Storage Pit Irrigation,the content of nitrate nitrogen has a certain correlation between different soil depths,and among the vast majority of soil layers,nitrate content reaches significant relevance at the 0.01 level(on both sides),this suggestes that there is a good correlation between them.Through Mathematical Statistics-Principal component analysis and factor analysis,we draw the following conclusion:Under the Water Storage Pit Irrigation,we only need to lay three sampling points on 0~20cm 、 40~60cm and 80~100cm soil layers and each soil-layer lays six points——which does not across the pit and of fruit trees 30 cm distance(b30),which acrosses the pit and of fruit trees 30 cm distance(g30)、50cm distance(g50)、120cm distance(g120)and which betweenacrosses the pit and does not across the pit and of fruit trees 75 cm distance(z75),110 cm distance(z110)to effectively monitor the content of soil-nitrate nitrogen below the surface within the depth of 0~200cm around fruit trees.Further use of measured data to validate the conclusions of the test,the results show that it has a high prediction accuracy,reliability is better.