Behnaz Attaeian; Ali Badrestani; Saeid Khosrobeigi Bozchelui; Mohammad Mehdi Artimani
Abstract
Soil organic carbon as a key factor in soil stability and fertility is considered as one of the important environmental challenges in the context of climate change. The aim of this study was to determine soil organic carbon zonation in Gonbad paired-watershed, Hamedan province. In this research, the ...
Read More
Soil organic carbon as a key factor in soil stability and fertility is considered as one of the important environmental challenges in the context of climate change. The aim of this study was to determine soil organic carbon zonation in Gonbad paired-watershed, Hamedan province. In this research, the information of meteorology, soil science and erosion and sedimentation study of Gombad watershed was used, including the information of 49 profiles in the 0-15 cm soil layer. After collecting data, tests of normality (Shapiro-Wilkα test <0.05), homogeneity of variance, and then the relationship between independent variables and organic carbon were performed using Pearson's linear correlation in SAS software. Also, determining the most effective independent variable using multivariate analysis, PCA factor analysis was used in XlStat 2.1 software. In order to determine the distribution and amount of soil organic carbon in the Gonbad representative watershed, modeling using SVM support vector machine learning algorithms and RF random forest was used in R software.The results showed that 78.18% of soil organic carbon changes depend on four components. Clay and nitrogen percentage were selected as the most effective variables on soil organic carbon content, so that the first component of clay content explained 34% and the second component nitrogen explained 18% of variations. According to the results of the implementation of the SVM and RF Models, the SVM model with a CE factor of 0.86 and RMSE of 0.05 in the test stage is a more accurate model in this study.
Jaber Sharifi; Amrali Shahmoradi
Abstract
Vegetation changes rangelands, that usually occurs in the composition and structure of vegetation over time. On the other hand, human factors, especially rangeland management, play an important role in maintaining stability or degradation. The purpose of this study was to investigate the dynamics of ...
Read More
Vegetation changes rangelands, that usually occurs in the composition and structure of vegetation over time. On the other hand, human factors, especially rangeland management, play an important role in maintaining stability or degradation. The purpose of this study was to investigate the dynamics of vegetation under the local management was carried out from 2008 to 1391. To do this, main vegetative stepic regions of the factors related to crown cover, density and abundance were determined by multi-year and group species, during the three transects 500 m in 30 plots (5/1 × 5/1 meter) as well as soil moisture and organic carbon were measured. The results showed that a four-year period, In the vegetation of perennial grasses, such as Festuca ovina, Alopecurus aucheri, Bromus tomentellus and Koeleria caucasica their variation was due to rainfall in the growing season, there was no significant difference between study years. In shrub cover such as Onobrychis cornuta and Astragalus aureus were significantly different between years of study due to annual precipitation fluctuations and soil moisture moisture content. In perennial forbodies, such as Scorzonera radicosa, Polygonum alpetre and Veronica orientalis were affected by precipitation seasonal and there was a significant difference between years. Changes in soil organic carbon and the process is slow. Therefore the results of the survey year to year changes in vegetation,climate changes and soil moisture also how the soil erosion condition can as an appropriate guide for the correct current methods used for management of rangeland ecosystems.
