Soil Health Evaluation And Utilization Suggestion In Guanzhong Plain Area

Soil is an important material basis for human survival,food security and ecological environment quality.Soil health depends on the ability of soil to maintain biological production capacity,improve environmental quality and promote biological health functions within the ecosystem boundary.The Guanzhong Plain is the fourth largest plain in China,occupying an important position in the agricultural production of Shaanxi Province,and its soil health is related to the quantity and quality of grain in the province.Based on the collection and analysis of soil samples and the collection of relevant data,this paper systematically analyzes the relevant indicators of soil health in the Guanzhong Plain and their spatial distribution,constructs the soil health evaluation index system of the Guanzhong Plain,uses the comprehensive index method to evaluate the soil health status in the Guanzhong Plain,and puts forward corresponding suggestions for soil utilization in different health areas.It not only explores an effective soil health management model,but also provides a reference for ensuring the sustainable use of soil in the Guanzhong Plain and protecting the soil environment.The main results achieved are as follows:(1)The basic soil properties and spatial distribution characteristics of the Guanzhong Plain were analyzed.The soil bulk density in the Guanzhong Plain ranged from 0.8-1.68g/cm~3,which was higher in the southwest and low in the northeast.The soil porosity ranged from 0.42-0.51,which was opposite to the spatial distribution trend of bulk density.The p H ranged from 6.16-8.56,and the whole gradually increased from south to north,and the soil organic matter content ranged from 7.68-21 g/kg,and was concentrated between 9-13.39g/kg,and the overall showed a gradual decrease from southwest to northeast.The contents of alkaline hydrolyzable nitrogen,available phosphorus and available potassium ranged from3-11 mg/kg,8-28.35 mg/kg and 79-515 mg/kg,respectively,showing the distribution of high in the southwest and low in the northeast.The soil heavy metals As,Cu,Ni and Pb ranged from 10.15-15.11 mg/kg,20-42 mg/kg,25-55 mg/kg and 16-124 mg/kg,respectively,showing a decreasing trend from southwest to northeast.The NDVI value of the Guanzhong Plain was between 0.06-1,which was in good condition,and the NPP range was between0-900,showing the characteristics of high in southwest China,low in northeast China and Xi’an.Habitat quality ranges from 0-0.9 to 0.3,mostly from 0-0.3,and overall at a low level.(2)The soil health evaluation index system in the Guanzhong Plain was constructed.Based on the principles of effectiveness,sensitivity,practicality and versatility,combined with the actual situation of the Guanzhong Plain area,an evaluation index system consisting of 22 indicators in five aspects,including climate,topography,soil fertility,soil environment and land surface coverage,was selected,and the index weights were determined based on the analytic hierarchy method,among which the higher weight indicators were Ni,As,Zn,Pb and other heavy metal elements,the weight was between 0.069-0.074,and the lower was the climate indicators such as accumulated temperature,annual precipitation,and annual average temperature.The weight values were between 0.019-0.024,and a soil health evaluation method based on the comprehensive index method was proposed.(3)The soil health status and spatial variation characteristics of the Guanzhong Plain were evaluated.The comprehensive index of soil health in the Guanzhong Plain was between 0.58～0.82,and the average index was 0.70,and the overall condition was good,and the soil health status gradually increased from southwest to northeast.Among them,healthy(comprehensive index 0.73-0.82)soil accounted for 18% of the total soil area,mainly distributed in the eastern edge of central Guanzhong region;micro-sub-health(comprehensive index 0.70-0.73)soil accounted for 38% of the total soil area,mainly distributed in the northern and northern edge areas of Guandong;mild sub-health(comprehensive index 0.67-0.70)soil accounted for 23% of the total soil area,mainly distributed in the southern Guanzhong region;moderate sub-health(comprehensive index0.58-0.67)soil accounted for 21% of the total soil area,mainly distributed in the southern Guanzhong region.The soil health levels of the four prefecture-level cities were Weinan(0.72),>Xianyang(0.70> Baoji(0.68)> Xi’an(0.67).(4)Suggestions for soil utilization in different health areas were proposed.The evaluated healthy soil areas should strengthen soil protection and improve the comprehensive benefits of soil utilization;Micro-sub-health areas should improve vegetation cover and increase soil fertility by increasing organic fertilizer to mitigate the impact of climatic conditions on soil health.Mild sub-health areas are mainly affected by slope,and soil health should be improved through engineering measures such as soil leveling and changing land use methods.The moderate sub-health area was mainly affected by the slightly higher soil heavy metal content and lower soil fertility,and the soil health status should be improved by improving the soil environmental quality and soil fertility.