基于熵权法的不同土地整治年限的土壤养分含量评价

Evaluation Soil nutrient content under different years of land consolidation based on Entropy-weighted Method

为探明土地整治对土壤养分的影响,并进一步探究不同年限的土地整治工程对土壤含碳量、有效磷浓度和速效钾含量的储存能力的影响规律。本研究以陕西省渭北台塬地区土地整治项目为例,通过开展野外试验对土地整治前后不同年限的玉米地和苹果树地的土壤养分进行测定,并结合熵权法对土地整治条件下的土壤物养分含量进行等级评价。研究结果表明:土地整治后表层土壤总碳含量随着整治年限增加而不断增加,但增幅有限;土地整治对表层土壤总有机碳含量的变化影响最大,对土壤的酸碱度基本没有影响。苹果树地的表层土壤的多年总碳含量远高于玉米地的总碳水平,不同深度土壤的含碳量熵权比重规律一致,且整治多年后表层土壤含碳量才能达到良好状态,20~40 cm的土壤含碳量水平逐年提高。土地整治后土壤有效磷含量和速效钾含量均较整治前显著增加,有效磷浓度随着土地整治年限波动剧烈,增加了土壤有效磷浓度和速效钾含量两个指标之后,不同土地整治年限的土壤养分评价水平较土壤含碳量整体提高了一个等级。土地整治3 a之后,玉米地的土壤养分状态即可达到优秀等级;土地整治多年之后,苹果树地的表层土壤养分含量才可达到优秀等级;土地整治3 a之后,苹果树地20~40 cm的土壤养分即可达到优秀等级。本研究为土地整治背景下的土壤养分含量的分析和评价提供相应的方法。

Analyzing the effects of different years of land consolidation projects on the storage capacity of soil carbon content,available phosphorus concentration and available potassium content can help to explore the effects of land consolidation on soil nutrient content.Taking the land consolidation project in Weibei tableland of Shaanxi Province as an example,the soil nutrient content of maize fields and apple tree fields in different years before and after land consolidation were determined by field experiments,and the soil nutrient content under land consolidation was graded by the entropy-weighted method.The results showed that the total carbon content of surface soil(0~20 cm)increased with the years of land consolidation,but the range of increasing was limited.Land consolidation had the greatest impact on the change of total organic carbon content of surface soil,while there was no difference of soil acidity and alkalinity.Over the years,the total carbon content of apple tree fields was much higher than that of maize fields.Soil carbon content in different depths had the similar trend of entropy weight,and after many years of land consolidation,surface soil carbon content can reach a great level,but the level of soil carbon content in 20~40 cm was increasing year by year.The content of available phosphorus and available potassium in soil increased significantly after land consolidation,and the concentration of available phosphorus fluctuated sharply during the years of land consolidation.After the increasing of soil available phosphorus concentration and available potassium content,the level of soil nutrient content increased at least one level during land consolidation projects.After three years of land consolidation,the soil nutrient content of maize fields can reach the great level;after many years of land consolidation,the nutrient content of surface soil of apple tree fields can reach the great level;after three years of land consolidation,the soil nutrient of 20~40 cm of apple tree fields can reach the great level.This study can provide a method for the analysis and investigation of soil nutrient content under the background of land consolidation.