Study on the Impact of Exclosures on the Physicochemical Properties of Rangeland Soil (Case Study: Northern Golestan Province, Sufikam Rangelands)

Introduction: Overgrazing can have detrimental effects on the physical properties of soil in rangelands. Among the remedial methods for degraded soils, increasing rangeland fertility and striving to improve soil structure stability, reducing livestock trampling through grazing restrictions, are highlighted. Therefore, exclosure is one of the simplest remedial techniques, which involves preventing livestock access to all or part of a rangeland for one or more consecutive years. Thus, research on the effects of exclosure on the physical and chemical properties of soil in various regions helps determine the importance of this practice in different ecosystems. Based on existing studies, converting grazed lands into exclosures appears to be a suitable option for rehabilitating degraded soils. Establishing exclosures in degraded lands is an effective method for revitalizing degraded soils. This research examines how exclosures affect the physicochemical properties of degraded soils in the Sufikam rangelands in the northern part of Golestan Province.
Material and Methods: In this study, soil samples were collected from 60 points in both degraded exclosure rangelands and natural rangelands. Subsequently, soil characteristics including organic matter, soil aggregate stability, electrical conductivity, acidity, SAR, ESP, and the percentage of clay, sand, and silt were measured. After determining and calculating the mentioned parameters, the normality of the data was assessed using the Shapiro-Wilk test. To compare the exclosures and natural rangeland, t-test and Wilcoxon were employed in the R environment.
Results and Discussion: The results indicate differences in electrical conductivity, acidity, organic matter, particle stability, SAR, and ESP concentrations between the two study areas. The clay content in the exclosures area (25.19) was higher than in the natural (22.79), and the sand content in the natural rangeland (32.62) was significantly higher than in the exclosures (29.43). The clay content in the exclosure area has increased compared to the natural area, while the sand content in the natural area was significantly higher than in the exclosure area. The Pearson correlation between soil parameters in the exclosure area showed that the correlation between organic matter and soil aggregate stability (0.71), as well as between pH, EC, SAR, and ESP (0.84, 0.92) was positive. There was a negative correlation between organic matter and soil aggregate stability with pH (-0.93, -0.68), EC, SAR, and ESP (-0.25,-0.31).
Conclusion: The use of exclosures can contribute to the stability of soil particles and improve land performance. Soil stability is a crucial feature in maintaining desirable agricultural practices and achieving sustainable land performance. This study demonstrates that the use of exclosures as a suitable and effective management practice can enhance rangeland health and improve the physicochemical properties of the soil. Therefore, it is essential to consider exclosure treatment as a key component in the design and implementation of natural resource management plans. The results of this study indicate that the implementation of grazing exclosure in rangelands leads to positive changes in soil properties and contributes to the increase in vegetation cover and the rehabilitation of the rangeland ecosystem. Therefore, grazing exclosure is presented as an effective management method for rehabilitating degraded soils. Implementing grazing exclosure programs alongside other corrective measures, such as planting suitable rangeland species, can increase soil stability and fertility and contribute to the natural vegetation restoration. Consequently, in rangeland management planning, the use of grazing exclosure as a suitable and cost-effective approach should be considered.