Department of Natural Resources, Arak Branch, Islamic Azad University, Arak, Iran.
Department of Natural Resources, Torbat-E-Jam Branch, Islamic Azad University, Torbat-e-Jam, Iran.
Environ Monit Assess. 2021 Aug 3;193(9):549. doi: 10.1007/s10661-021-09334-1.
The study of the variability of physical and chemical factors of soil due to different intensities of livestock grazing can help in the management and maintenance of soil and vegetation. Accordingly, the effect of livestock grazing intensities on soil properties and vegetation in Bozdaghin rangelands of North Khorasan province was investigated. To investigate the effect of different livestock grazing intensities, Three 5-hectare plots in the study area were determined under different treatments (ungrazed (UG), moderate grazing (MG), and heavy grazing (HG)), and the effect of three grazing intensities on vegetation and soil physicochemical and erodibility properties (SPEP) was evaluated. The soil sampling process was performed at depths of 0-15, 15-30 cm and SPEP including soil saturation moisture (SSM), soil texture (percentage of clay, sand, and silt), absorbable potassium (K), electrical conductivity (EC), soil organic matter (SOM), absorbable phosphorus (P), acidity (pH), and bulk density were evaluated, and Soil Erodibility Index (SEI) was calculated by implementing the modified clay ratio relation. To assess the impact of various grazing intensities on all measured characteristics, multivariate analysis of variance (MANOVA) and Duncan tests were utilized to compare the means and their grouping. The results showed that HG compared to MG causes worrying consequences in the first soil depth. Also with increasing grazing intensity, plant production percentage (P < 0.05) and vegetation density (P < 0.01) decreased, and the amount of bare soil (P < 0.01) increased. Also, with increasing grazing intensity, the amount of pH, EC, clay, saturated moisture, and N decreased (P < 0.01), but the amount of silt, sand, K, P, calcium (Ca), lime, and SOM increased (P < 0.01). UG improves soil quality, MG intensity causes optimal conservation and utilization of soil resources, and HG intensity causes severe changes in rangeland soil properties. In areas with MG intensity, due to the increase of the percentage of vegetation (an increase of SOM and prevents the direct impact of raindrops on the soil aggregates) and as a result improvement of soil structure and texture, an increase of water infiltration, and decrease of runoff, and the rate of soil erodibility and water erosion, the rangeland soil decreases and results in sustainable production. This results in optimal conservation and utilization of soil resources. So to sustainably exploit and balance the conservation of biodiversity, livestock production, and soil carbon and nitrogen management, MG is recommended.
由于不同强度的牲畜放牧，土壤的物理和化学因素的变化研究有助于土壤和植被的管理和维护。因此，研究了北呼罗珊省博兹达金牧场不同牲畜放牧强度对土壤性质和植被的影响。为了研究不同牲畜放牧强度的影响，在研究区域内确定了三个 5 公顷的地块，进行不同处理（未放牧（UG）、中度放牧（MG）和重度放牧（HG）），并评估了三种放牧强度对植被和土壤物理化学和可蚀性特性（SPEP）的影响。土壤采样过程在 0-15、15-30 cm 的深度进行，SPEP 包括土壤饱和水分（SSM）、土壤质地（粘土、沙子和粉土的百分比）、可吸收钾（K）、电导率（EC）、土壤有机质（SOM）、可吸收磷（P）、酸度（pH）和容重，并通过实施改良的粘土比例关系计算土壤可蚀性指数（SEI）。为了评估各种放牧强度对所有测量特征的影响，采用多元方差分析（MANOVA）和邓肯检验比较平均值及其分组。结果表明，与 MG 相比，HG 在第一个土壤深度造成令人担忧的后果。随着放牧强度的增加，植物产量百分比（P < 0.05）和植被密度（P < 0.01）下降，裸土量（P < 0.01）增加。随着放牧强度的增加，pH 值、EC、粘土、饱和水分和 N 的量减少（P < 0.01），但粉土、沙子、K、P、钙（Ca）、石灰和 SOM 的量增加（P < 0.01）。UG 改善了土壤质量，MG 强度导致土壤资源的最佳保护和利用，HG 强度导致牧场土壤性质的严重变化。在 MG 强度的区域，由于植被百分比的增加（SOM 的增加和防止雨滴直接对土壤团聚体的影响）以及土壤结构和质地的改善、水入渗的增加、径流量的减少以及土壤可蚀性和水蚀率的降低，牧场土壤减少，导致可持续生产。这导致了土壤资源的最佳保护和利用。因此，为了可持续地开发和平衡生物多样性保护、牲畜生产以及土壤碳氮管理，建议采用 MG。
