Search published articles


Showing 3 results for Grazing Management
Effects of Climate and Long-Term Grazing Exclusion on Selected Soil Biological Quality Indicators in Rangelands of Central Zagros
M. Sheklabadi, H. Khademi, M. Karimian Eghbal, F. Nourbaksh,
Volume 11, Issue 41 (10-2007)
Abstract
The effect of overgrazing on vegetation changes in central Zagros has been studied by a few scientists, but there is no detailed information on the impact of such practices on soil properties. The objective of this study was to assess the effect of climate and grazing management on selected soil biochemical properties. Fourteen experimental range sites protected against grazing as well as their adjacent overgrazed sites in Chadegan, Pishkuh and Poshtkuh were selected. In each site, samples were collected from the depths 0-5 and 5-15 cm. Soil organic C (OC), microbial biomass C (MBC), total nitrogen (TN), organic C to total N ratio (C/N), microbial biomass C to organic C ratio (Cmic/Coc) and metabolic quotient (qCO2) were measured and/or calculated. The results showed that the lowest SOC, MBC, TN and Cmic/Coc occur in Chadegan due to low fresh materials input. The above parameters in Pishkuh and Poshtkuh regions are 2.5 to 3 times greater than those in Chadegan area. Grazing intensity in Pishkuh is less than that in Poshtkuh region and there is no significant difference between grazed and protected sites in Pishkuh. But, there is a significant difference between grazed and protected plots in Poshtkuh due to a higher grazing intensity. Higher Cmic/Coc and lower qCO2 suggest that the quality of organic matter is better in Poshtkuh and Pishkuh. In conclusion, highly degraded rangelands in Pishkuh and Poshtkuh seem to be able to recover very quickly with proper management, while Chadegan region needs a much longer period of time to restore.
Potential Soil N Mineralization in Rangeland Ecosystems with Long-Term Free Grazing and Ungrazing Regimes in Different Climates
M. Riahi , F. Raiesi,
Volume 16, Issue 59 (4-2012)
Abstract
Mountainous landscapes in Central Zagros are mainly used as grazing rangelands to feed animals and are heavily degraded. Overgrazing may impose a negative effect on rangeland productivity and sustainability through significant changes in soil properties. Soil nitrogen (N) mineralization is one of the key biological processes that might be affected by biotic and abiotic factors including range grazing regime or intensity. The primary objective of this study was to assess the effects of rangeland management (grazing and ungrazing regimes) on soil N mineralization in natural rangelands of Chaharmahal VA Bakhtiyari province. Three range management regimes including a) long-term ungrazed, b) controlled grazed and c) freely- (over)-grazed plots in a close vicinity were selected in three regions consisting of SabzKouh (protected from grazing for 18 years), Boroujen (protected from grazing for 23 years) and Sheida (protected from grazing for 2 years), and soil samples were collected from 0-15 cm depth for some physical and chemical properties. Soil N mineralization was measured under standard laboratory conditions. At SabzKouh, the effect of range management on the cumulative N mineralization and the proportion of N mineralized (%) was significant (P<0.05) and ungrazing regime resulted in 89% and 96% increases in soil N mineralization in ungrazed rangelands compared with controlled grazed and freely- grazed rangelands, respectively. Similarly, soil N mineralization was significantly greater (P<0.05) in ungrazed rangelands (3.3- to 3.5-folds) than in controlled grazed and freely-grazed rangelands at Boroujen site. However, at Sheida site with short-term ungrazing period and cropping history there were no significant and considerable differences in soil N mineralization among the three grazing regimes. Briefly, degraded rangelands at SabzKouh and Boroujen sites seem to recover rather quickly from long-term overgrazing with a proper grazing management, while rangeland ecosystems at Sheida site need a much longer period for steady-state conditions and for improvements in soil quality and fertility after long-term soil degradation and disturbance.
The Effects of Long-term Grazing Management on Vegetation and Some Soil Characteristics (A Case Study: Hamzavi Research Station in Hanna- Semirom, Isfahan)
M. Kazemi, H. Karimzadeh, M. Tarkesh Esfahani, H. Bashari,
Volume 22, Issue 4 (3-2019)
Abstract
Evaluating the possible relationships between vegetation and environmental characteristics can assist managers to identify effective factors influencing plants establishment and to characterize various vegetation communities. This study was aimed to evaluate the effects of long term grazing exclusion ( more than 33 years) and the controlled grazing system (resting – rotation grazing system) on the vegetation distribution and some soil properties in the Hamzavi research station in Hanna area-Semirom, Isfahan. Six transects (three parallel transects and three transects perpendicular to the general slope of the area) were established in each area and 10 square plots with the size of 2m2 were placed along each transect; then, the cover percentage, production and list of all plant species were recorded. In each area, eighteen plots were collected randomly and in each plot, five soil samples were collected from 0-30 cm of the soil and then the samples were mixed and one sample of the compound was selected as an evidence plot. Soil properties such as pH, EC, CaCO3, organic carbon, absorbable phosphor, total nitrogen, K, Ca, Mg, soil saturated percentage, cation exchange capacity, soil clay, silt, sand and fine sand contents were measured in the soil laboratory. The independent t test was used to compare the vegetation characteristics in two areas. Cation exchange capacity, CaCO3, gravel percentage, soil phosphor content and grazing management were identified as the most discriminative factors in separating vegetation communities based on Canonical correspondence analysis (CCA) and cluster analysis. Controlled grazing management significantly modified some soil characteristics and increased the production (352 versus 184.2 kg/ha) and vegetation cover percentage (25.46 versus 18.37), as compared to the exclusion area (α= 5%). The vegetation density was increased significantly in the exclusion rather than controlled grazing area (3.03 versus 2.02 plant/m2). This study, therefore, revealed that controlled grazing management was more effective on improving some soil quality and vegetation characteristics rather than p long term grazing exclusion in the semi-arid ecosystems. So, avoiding long term grazing exclusion in semi-arid rangelands is suggested.

Page 1 from 1     

© 2024 CC BY-NC 4.0 | JWSS - Isfahan University of Technology

Designed & Developed by : Yektaweb