مجله مرتع
سال پنجم شماره 3 (پیاپی 19، پاییز 1390)

The amount of forage production is basically used to determine grazing capacity. Measuring the amount of rangeland production to determine the carrying capacity, is one of the most important factor. Various methods depend on vegetation type, density, percentages of canopy cover, affordable time, accuracy, experts experience, etc., have been proposed. Measuring the amount of forage production with clipping and weighting method is the most reliable method, but it is time consuming and expensive. So we must choose an accurate and simple method with less cost and time consumption. One of these methods is application of grassmaster that is one of the capacitance meter type. The objective of research was investigation on grassmaster efficiency comparing with clipping and weighting method in three types of grassland, alfa-alfa fields and shrublands in two growth stages (flowering and seed ripening). In each habitat along 2 transects, 200 plots (1m2) were used. In each plot production with clipping and weighting method and with grassmaster was measured. Data were analysed using SPSSversion 15 software. The Results showed that grassmaster in shrubland didn`t record any data. Therefore, grassmaster is not suitable for shrublands. In grassland and alfa-alfa field according to correlation coefficients, results were as follows: grasslands in flowering stage 97%), seed ripening stage (92%), cultivated alfa-alfa in flowering stage (61%), seed ripening stage (27%). So the best efficiency obtained for Grasslands.

Measuring forage quality of dominant species is a prerequisite of proper management in rangelands. In this research, nutrient values of seven species were evaluated at three Phenological (vegetative growth, flowering and seed production) stages. In this study, a completely randomized design with five replications was used in Bojnord rangelands. Species included: Sanguisorba minor, Onobrychis transcaspica, Onobrychis radiata, Astragalus brevidens, Melica ciliate, Agropyron repens and Agropyron pectiniforme. The measured forage quality parameters included: crude protein (CP), acid detergent fiber (ADF), dry matter digestibility (DMD) and metabolizable energy (ME). According to results, forage qualities in all of the studied species were higher in vegetative growth than flowering and seed production stages. CP, ME and DMD of the studied species were decreased approaching to the end of growing season, while ADF values were increased. Legumes had higher percentage of crude protein (14.53%) and the lower percentage of ADF (43.91%) in all phenological stages, while perennial grasses had CP and ADF of 8.1% and 54.14% respectively. High and low CP percentages were obtained in Astragalus brevidnes and Agropyron pectiniforme, respectively. According to the results, significant differences were observed among the species and phenological stages for all measured and calculated forage quality factors (p<0.01).

Spatial patterns of vegetation in a range type dominated by Bromus tomentellus and Astragalus verus in Feridan- Isfahan were studied. Four 50 m2 reference sites were randomly selected (5 by 10 m). All perennial species were counted and their coordination were recorded accordingly. Two approaches were used to measure average distance between plants including “Closest individual” and “Nearest-neighbor method”. Individual plants were counted in quadrates. Spatial patterns of vegetations were determined using three methods including, Point Pattern Analysis, Spatial Indices (Hopkines, Pielou, Johnson and Zimer Index) and Quadrate Indices (Green and Morisita Index). Results indicated that perennial species had randomized spatial patterns due to the relatively homogeneous environmental characteristics of studied area and also selective pattern of vegetation. Point pattern analysis had more accuracy because it considered all perennial species coordination. With sufficient sample size and appropriate quadrate size and shape, quadrate indices had acceptable accuracy. Hopkines index had more precision to determine spatial pattern of vegetation than Johnson, Zimer and Pielou indices. It indicated that spatial indices based on the plant to plant distance (Nearestneighbor method) had more precision than indices that derived from point to plant distance (Closest individual).

One of the key factors in managing a rangeland is to determine the relative preference of its major plant species by the grazing livestock. Preference value of plant species might change during grazing season and from one year to the next. The knowledge of animal grazing behavior and indigenous grazing systems are very important in range management, specially, in arid and semi arid rangelands. Different methods are introduced to determine the preference value of range plant species. In this study, feeding minutes and intake percentage efficiency were used to measure preference value of species in grazing season (April to September) of 2007 to 2009. The study area was located in semi step rangelands, Koh Panj, west part of Kerman province, Iran. A randomized complete block experimental design with a combined analysis in time was used to perform analytical analysis on obtained data. The results of feeding minutes showed that the annual grasses were the most preferred species as they were grazed in 45.5 percent of total grazing time. The maximum Intake Percentage of species refer to Agropyon desertorum by 53.6 percent, and minimum refer to Secale montanum by 32.8 percent. The maximum annual preferences value was occurred in 2008.

Understanding the vegetation dynamics of arid rangelands is a prerequisite for their proper management. Water stress is the most crucial environmental stress for vegetation in this region and long-term monitoring experiments are an important tool to investigate rainfall variability impact. This study was conducted on Aliabad rangelands for nine years (1378- 1386). The aim was examining the effect of rainfall variability (year, season and period) on production of plant species. For this purpose four dominant species were selected and their canopy cover and production were monitored every year along permanent line transect in random plots. Precipitation data were collected from nearby stations. According to data of rainfall, amount of cumulative rain was determined at various periods. Relationships between variables of annual yield and amount of cumulative rain were analyzed by simple and multivariate (stepwise) regression methods. The Results indicated that many of plant species are affected by rainfall variability. However, various species reacted differently to the rainfall variability in terms of production. According to this result, annual yield of, Artemisia sieberi, Ephedra strobilaceae, Zygophyllum eurypterum can be estimated by rainfall data, but Salsola tomentosa production did not have significant relationship with rainfall variability. Result of curve fitting showed that yield response in Ephedra strobilaceae and Artemisia sieberi are in two forms of power and quadratic, respectively.

The present study examines the relationship between vegetation and soil characteristics in addition to topographic factors to determine the most effective factors on the formation and establishment of vegetation in rangeland of Chaharbagh. After identifying the study area and determining the vegetation types, in each type along four 100 m transects, ten 2×2 m plots were put based on randomsystematic method. The size of sampling plots and their number was determined according to minimal area and statistical methods. Along each transect, two soil samples were taken from 0-20 cm and more than 20 cm depths. In addition, elevation, aspect and slope were recorded, too. Soil samples were transported to soil laboratory and properties of texture, acidity, electrical conductivity, potassium, nitrogen, phosphorus, organic matter and lime were measured. After data collection, TWINSPAN was applied to classify the vegetation. Four ecological groups (the same four vegetative types) were obtained. In order to analyze the relationship of soil and topographic properties with vegetation changes, PCA and CCA methods were used. The results of both methods were almost the same. Results showed that the occurrence and distribution of understudy vegetation is hugely affected by some soil factors including texture, nitrogen, potassium, organic matter and lime compared to other properties of soil and topographic factors.

LFA (landscape function analysis) is a rangeland ecosystem potential assessment procedure that its application is increasing in Iran. Our objective was to verifying soil surface indices evaluation using LFA at an arid coold season rangeland (Mazrae Amin rangeland). The study area is in Yazd province with 188 mm annual mean precipitation in centeral part of Iran. The LFA monitoring procedure generates three principal indices: soil stability, infiltration and nutrient cycling. LFA had been done with 10 replications then we tested those indices by regressing them against the field and laboratory measurements. Infiltration, stability and nutrient cycling, respectively measured using Cylinder infiltrometer, Emerson test and Wet oxidation. The results showed that all of LFA soil surface indices have moderately verification (R: 0.4-0.6). Stability index has highest verification (59.6%) and infiltration index has lowest verification (49.2%). The verification of nutrient cycling index was 53.4% too.

Plant diversity is one of the important and fundamental issues associated with community ecology. Detection of relationship between diversity and exploit methods is one of the most important challenges in natural resource. In this study that has been done in Boz Daghi arid and semi-arid rangelands in Maneh Samalghan county in North Khorassan province, the effects of enclosure on biodiversity using parametric models is considered. With selection of two enclosured and under grazing areas, the number of 100 plots with 1 square meter is randomly located. Diversity indices including Log normal, geometric, Log and Mac Author broken stick was evaluated using BIO-Dap software. The Chi-Square test was used to considering signification of estimated levels and expected density. The results shows that the frequency-grade curve of species in the enclosure region is located above of the frequency-grade curve of in grazed region and the grazed region is following of lognormal model indicates that this region has less dominant and rarely species and more species with average frequency. Furthermore, grazed region follows the both log and log-normal models that explains at first this region has been a uniform area and has been intended to log model that explains aarea under stress due to intensive grazing.

This study was conducted to document indigenous knowledge in Kalhor pastoralist nomad tribe, the biggest Kurdish tribe in the field of livestock production. The methodology was qualitative approach using in depth interview and focused groups techniques. The geographic location of the tribe is Gilane-Gharb county in Kermanshah province. Qualitative purposive sampling and content analysis were used. Result showed that to achieve optimal production, feeding patterns must be changed in different physiological stages of livestock such as pre mating, pregnancy and lactation. Also they consider the range source of forage supply. They divide rangelands according to grazing systems named Thaghat Khor and Halachair and estimate range quality in relation to some factors including vegetation and water availability. Result showed that these pastoralists divide rangelands as Dool and Pal according to their livestock nutrition requirements.

This research is trying to compare three methods of utilization. Collective, Private and council.In order to assess the influence of common right of ranchers on rangeland condition and forage production, this study carried out in Damavand Summer Rangeland in Amol County. The aim is to find the best method of utilization based on ecological sustainability. 15 ranches were selected according to the method of utilization. 88 questions via direct interviews were completed. Range conditions were measured using four-factor method and forage production was estimated by clip and weigh in method. The findings indicate that three methods of utilization significantly influenced rangeland condition and forage production. Here private property significantly showed the best condition and forage production. Also Spearman correlation test showed that between the number of ranchers and number of livestock in each range with condition and forage production is negatively related at 99%. Results showed that type common right of ranchers increase the competition for having more livestock and consequently more utilization of the ecological potential rangeland. For maintaining the ecological sustainability and social equilibrium in rangeland, it is recommended to purchase the common right of small ranchers to reduce the number of livestock and ranchers.