نشریه مرتع و آبخیزداری
سال شصت و سوم شماره 3 (پاییز 1389)

Desert and marginal lands of playas which are covered with halophyte shrubs, play a great role in supply of forage for livestock as winter rangelands. In this research, plant samples were collected from four palatable halophyte species for Zandi sheep of Qom desert rangelands including Seidlitzia rosmarinus، Halocnemum strobilaceum، Alhagi camelorum and Tamarix passerinoides in two phenological stages (vegetative growth and seed ripening). The plant samples were dried and analyzed by AOAC methods for qualitative indices such as: crude protein (CP %), acid detergent fiber (ADF %), dry matter digestibility (DMD %) and metabolizable energy (ME). The results showed significant differences (p<0. 01) between different species and phenological stages. Halocnemum strobilaceum had the highest CP% in vegetative stage while Tamarix sp. had the lowest one in seed ripening stage. The highest and the lowest DMD% and ME (mj) were related to Seidlitzia sp. and Tamarix sp., respectively. Also, according to Duncan’s test, interaction effects of plant species and growth stages were significant by quality indices (p<0. 01). In most of species, the amount of CP% decreased with progressing phenological stages while ADF%, increased. Meanwhile, autumn and winter in the first type (Ha. st- Se. ro) and late winter and spring in the second type (Al. ca- Se. ro), were determined as the most suitable period for animal grazing.

Yazd province because of cultural and historical background of the distant past always had known as ambitious and hard-working people. Manifesting multiple efforts of these people is seen in water harvesting. In Yazd province, background issues such as evaluation and assessment of water, ownership and agricultural water share refers to the distant past which has been changes over time in type and form. The purpose of this article, meanwhile a short review of management method and operation of water with a focus on Mirab, the evolution of ownership, irrigation circuit changes over time and changes in water price has been paid. Research methodology is single-type reticulum (monographic). Location research has been Chrkhab village of Yazd. Irrigation cycle of village has changed in four stages to the final cycle of water from 16 days to 21 days and 20 hours has become at present. Now, 53 Owner of the well are operating. In this study, according to the classification made, those of their right of water irrigation period were less than one hour (small landowners). This group, forming the highest frequency, equivalent of 33/6 percent was. According to the results, in extent of water right distribution between owners and various whiskers, the owners try to allocate more shares for them in order to play higher roles in the rural society. Study of the current water price changes for fifty years shows, the price of general inflation society has not follow. In this review the current water price increase rate (growth rate), 0/12 percent obtained.

This study investigates the relationship between litter quality and aerial parts of plant on C, N, K, P and C/N ratio of soil in four rangeland species including Agropyron intermedium, Bromus tomentellus, Eurotia ceratoides and kochia prostrata. After recognizing the sites of these species in Hamand Absard located in 65 km of northern Tehran, at the end of growing season, samples of litter, aerial part of plants and soil were taken using systematic- random method. For this purpose, five transects, each of l00 m length and 50 m spacing were taken. Two plots in each transect with an area of 1 m2 were established. In each plot, soil samples under plants and without plant area (control samples) at depth of 0-30 cm were taken. The C, N, P, K, EC, pH and texture of samples were analyzed in laboratory. Analysis of variance, Dunnett's test and t-student test were applied to the data. Results show that in the aerial part of plant, C and C/N ratio of Agropyron intermedium and P, K and N of Kochia prostrata are higher than other species. In case of litter, C, K and C/N of Eurotia ceratoides and N and P of Kochia prostrata showed higher values. However the results of soil samples show that C of Agropyron intermedium, N and C/N of Kochia prostrata and K of Bromus tomentellus are higher than other species. Totally, Kochia prostrata showed the best litter quality, decomposition rate and effects on soil.

Rangeland ecosystem contains various patches with different functions. Structural and functional characteristics of rangeland patches are changed by management practices and can be used to interpret management effects. The structural and functional characteristics of fertilized patches in two rangeland ecosystems of Ghareh Ghir and Maraveh Tapeh were measured and analyzed in this study. A group of measurable and simple indices of landscape function analysis (LFA) methods were used to evaluate these characteristics. Five structural characteristics such as: the number of patches, total patch area, patch area index, landscape organization index and inter patch length mean on the east and western aspects of Ghareh Ghir and Maraveh Tapeh were measured. On the basis of statistical analysis, the structural characteristics of patches in the east and western aspects of the two areas (Ghareh Ghir and Maraveh Tapeh) were highly significant (P<0.05). The landscape organization indices of the western aspects of the two rangelands are higher than the other side (eastern aspects) whereas the western aspects have more dense vegetation cover than the eastern aspects. The landscape organization index shows the value of landscape potential. Therefore, high level of landscape organization index at western aspects could be on the basis of area and dense shrub patches at Maraveh Tapeh and lichen with moss at Ghareh Ghir rangelands. In conclusion, the best ecological indicator of western aspects at Ghareh Ghir landscape are vegetative forms of lichen and moss and the best ecological indicator of western aspects at Maraveh Tapeh landscape are vegetative forms of shrubs.

The objective of this research was to study the relationships between edaphic and topographic factors with distribution of plant species. For this purpose, current study was conducted in Eshtehard rangelands of Tehran province. The sampling method was randomized–systematic and in each sampling unit, three parallel transects with 750 m length containing 45 quadrates (according to vegetation variations) were established. Quadrate size was determined for each vegetation type using the minimal area; hence suitable quadrate size for different species was determined 1*2m (2 m2). Soil samples from the beginning and end of each transect at two depths 0-30 and 30-80 cm were taken and the measured soil properties included gravel, texture, organic matter, lime, pH and electrical conductivity. To analyze the environmental data, PCA was considered. The results indicated that gravel, texture, EC and lime play the main role in the distribution of plant species.

The Mahabad River Watershed has been exposed to severe erosion as a result of landuse change. The aim of this study is to quantify the amount of sediment yield and the relationship between land use change and slope. Different sources such as geologic and topographic maps, satellite images, hydrometric as well as meteorological data were used to extract and gather the information needed for this research. Six factors including altitude, slope, precipitation, rock erodibility, time of concentration and land use were specified as the most effective factors. The overlapping of the six factors maps resulted in the preparation of sediment delivery potential map. The distribution maps prepared on each of these parameters and their overlaps have shown that areas with more severe slopes are categorized as highly susceptible to erosion. However, in areas with resistant rocks, change of land use has been the determining factor. Comparison of water and sediment discharge data of 1996-97 with 2001-02(similar annual water volume) showed that the sediment yield has increased. Studying land use map prepared using satellite imagery of 1987 and 1998 showed that land use of the area has severely changed from pasture to dryland farming. This factor has also caused the intensification of mass movement recently occurred in the area. Landuse is the only parameter modified by human, and it is the only one which can be quickly and effectively changed. Hence, it seems that the upstream areas in the south and southwest of the basin with low concentration time, steep slope, high erodibility, high amount of precipitation, and the landuse of forest and pasture mixture as well as alluvial terraces with fine and granular sediments are the most sensitive areas which need protecting and control measures.

One of the major sectors of water loss is the loss of rain runoff. Kirkby (2001) the Effect of soil surface characteristics in the production of runoff in time and space scales concluded that soil properties such as undulating, soil texture and structure on the amount and spatial pattern of runoff are effective. In this research that was conducted in the Latian watershed, twenty experimental plot Manufacturer runoff collected at the end they were constructed Bankettes longitudinal dimension equal to the width of runoff plot, poster collection, depth 0.5 meter and width of 0.5 meter was constructed. Depth of rainfall runoff from natural and 12 each with artificial rainfall intensity rainfall simulator with 8 mm to 42 mm per hour was established, was measured. Since the end Bankettes within plots were covered with plastic, all collected runoff was measured on it. The plastic cover was pulled out of water completely penetrating Bankette. After 24 hours on Bankette collected water depth was measured so that how deep the penetration has. After the plastic cover was created to prepare for the next runoff is measured. Part of the rainwater Collected in a barrel with a volume of 220 liter were stored on the first of the spring was covered with a plastic cover to prevent evaporation of collected water for limited irrigation water supply in June to 30 July to 15 of 62 mm were used and in forage maize plots nine branches were planted SC704. The results showed that compared with the yield ratios of 1:1, 2:1 and 3:1 (ratio of surface runoff collected rain Manufacturer of level of corn planted) yield of forage corn, respectively 9.6, 22.6 and 28.8 T.ha respectively. Whereas in the control treatment, there was no water limitation and the rate of 41.5 T.ha of forage maize yield was, The total water used in the three above treatments, respectively 616, 696 and 776 mm was. (In addition to direct rain water collected from runoff) and supplementary irrigation water depths in all three treatments was 62 mm. Thus yield respectively 23, 55 and 69 percent compared to the control (grown with full irrigation) has been. In this research the effect of vegetation and soil in runoff amounts were compared.

Assessment of watershed management activities is one of the main subjects for future planning of practical projects and natural resources management. Due to the lack of any tool for assessment of watershed processes in many cases, distributed hydrological models can be useful. The purpose of this study was evaluation of watershed management activities in Kan Watershed by HEC-HMS (Hydrologic Modeling System). For this purpose, first by considering observed events, HEC-HMS model was optimized and calibrated. Then, for evaluating the effects of check dams on time of concentration, it was calculated before and after of check dam's construction by use of field observations and vegetation cover improvement was also estimated after the project. These parameters were imported to HEC-HMS to find out the effects of watershed practices and then flooding condition was simulated. For assessment purposes, peak discharge and flood volume were calculated for “before” and “after” construction conditions. Results showed that check dams as mechanical measures had low effect on time of concentration while biological practices lead to decrease in curve number with an average value of 3.1. This effects result in decrease of peak flow and flood volume meanly 21% and 11%, respectively.

Our planet is threatened by nuclear wars, climate change and degradation of biodiversity. The first two dangers are relatively focused on, but biodiversity degradation is not properly considered yet. Species diversity is mostly composed of biodiversity and is considered an index of changes in ecosystems. Many of researchers think of higher species diversity as an index of bio-system’s stability. This research aimed to study parametric models of species diversity on range vegetations of study sites and relationship of ecological factors such as climate, soil and topography with diversity index. Four range sites were selected on different geographic areas in Isfahan province and randomly- systematic sampling was conducted to collect density data on plant species by quadrates along transects of each site during six years (2002-2007). Broken stick, log normal, logarithmic series and geometric series models were fitted for each site, and log normal showed to be the most proper model of distribution with P>0.05. LSD’s test indicated a significant different at? =1% level between species diversity of steppe1 and semi-steppe2 sites. Log normal model seemed to be the most proper model in all sites. Generally, when this model is fitted successfully communities are considered stable. On the basis of some related studies with this research, Hill () showed to be most proper index for species diversity in study sites, therefore effects of ecological factors such as soil, climate and topography on this index were studied by CCA method. Results of CCA revealed a high positive correlation between species diversity and percent organic matters of soil as well as precipitation levels and negative correlation with temperature.

Investigation and preparing of wind erosion intensity maps are the main objectives of this research. In this research, the working unit map was prepared and then nine effective factors in wind erosion according to IRIFR.E.A model are determined at each of seven homogeneous units. According to the results, active sand dunes and landuse change showed the highest value with the rate of annual sedimentation more than 6000 ton/km2 while lands surrounding the villages showed the least value with an annual rate of sedimentation of 150-500 ton/km2. Also considering whole area which is about 16161 hectares, around 1978 hectares are classified in low class of desertification; 7430 hectares in medium class while 6753 hectares in high and very high classes.