Soil Properties And Health Evaluation In Mufushan Mt.of Eastern Hunan Province

Soil is the basic material for plant growth and reproduction.In terrestrial ecosystems,soil plays an important role in food,fiber and energy production,water purification,soil and water conservation,C sequestration and climate mitigation,biodiversity maintenance and cultural heritage preservation.To fully understand the soil ecosystem service functions and its soil health in typical subtropical middle Mt.Of granite,17 soil samples of surface depth（0～20cm）was selected along an elevation gradient,and the soil physical,chemical and biological properties were analyzed.By using 3 kinds of soil health assessment tools,including MDS,HANEY soil health test and soil health comprehensive evaluation system（CASH）,the soil health was comprehensively assessed.The main results were listed as follows.In terms of soil physical properties,soil bulk density and compactness decreased significantly with the increasing altitude,while soil gravimetric water content,total porosity and capillary porosity,soil field water capacity,capillary water capacity and maximum soil water capacity increased significantly with the increasing altitude.With the increase of altitude,the water-stable aggregates in>0.25 mm soil were significantly increased,but the>0.25-0.053mm and<0.053 mm water-stable aggregates in soil were significantly decreased,and the average weight diameter（MWD）of soil was significantly increased.However,soil sand,silt and clay content had no obvious correlation with increasing altitude.In terms of soil chemical properties,with the increase of altitude,the soil p H increased,and the contents of soil organic matter,total N and alkali-hydrolyzable N increased significantly,indicating the improvement of soil N availability.Although the soil total P content showed an extremely significant increasing trend,the soil available P,total K and available K contents had no obvious correlation with increasing altitude.The contents of exchangeable Ca,Mg and available Fe,Mn and Zn in soil showed no obvious correlation with increasing altitude,but the content of available Cu in soil showed a significant increase trend with increasing altitude.Using the method of minimum data set（MDS）evaluation index of soil health,the results show that the MDS for soil health assessment in Mufushan Mt.included 9 indicators:bacteria,sand,Zn _Av,catalase,bulk density,MBN,0.25～0.053 mm aggregate,TK and Mg _EX.The soil health index increased significantly with the increasing altitude,and the value of soil health index in the high altitude zone was significantly higher than that in the low altitude zone.The application of HANEY soil health test tool showed that the scores of HANEY 2015 version and 2018 version soil health test tools increased with the increase of altitude,but the scores of HANEY 2018 version were higher than that of HANEY 2015 version.HANEY soil health test tool（2015 version and 2018 version）showed low scores.This suggests that HANEY soil health test tool may be unsuitable for soil health assessment in Mufushan Mt.Using the CASH soil health test tool,the comprehensive score of soil health increased significantly with the elevation.The comprehensive score of soil health in the high altitude zone was significantly higher than that in the low altitude zone.The soil health is degrading due to the strong human disturbance activities in the low altitude zone,while the soil is conserved in the high altitude zone.The CASH evaluation was consistent with the real status of soil health in Mufushan Mt.,and is applicable for soil health assessment.A comprehensive analysis of the 3 soil health assessment tools showed that the scores of soil health in the high-altitude sampling sites were significantly higher than those in the low-altitude sampling sites.In the MDS method,totally 40 physical,chemical and biological property indicators was selected,and finally 9 indicators were screened out.This is less than the 12 physical,chemical and biological indicators in CASH tool of soil health.In conclusion,the MDS tool of soil health assessment is the most suitable tool for soil health assessment in Mufushan Mt.