نشریه حفاظت و بهره برداری از منابع طبیعی
سال یکم شماره 3 (1391)

Soil condition and type of land use are the most important factors that directly determine soil infiltration rate and hence, control the creation of flood in watershed. In other words, the Curve number of each watershed shows its hydrological behavior and water regime during precipitations. This study was carried out on Maraveh-Tappeh watershed, Golestan province and its main object was produce the curve number map for the study area. Using GIS, the average weighted curve number of the watershed was 77 in humidity level of grade II and major part of the watershed area had curve number of 79. Results revealed that, the maximum number of curves during mean humidity reaches up to 97 and the minimum number to 60. Accordingly, high number of weighted average curve number could be an evident of low infiltration rate of watershed and increasing probability of flood occurrence owing to loess soil. In order to reduces water resources loss, it is necessary to implement basic practices at watershed in line with increasing of water infiltration rate and establishing water harvesting systems including pitting and contour furrow, combined with vegetation increasing projects such as seeding and shrub planting. Additionally, using the current curve number map and consideration to precipitation regime of the watershed, sustainable development plans for water resources management can be implemented and hence some solutions may be presented to manage water tensions and to control floods in this watershed.

Certain types of coordination and compliance of a particular type of land with specific uses are one of the fundamental prerequisites for achieving sustainable development of land. Today, there are extensive models for determining optimum use with respect to land and its ability. In this research project, for spatial organization and sustainable management of land use of Khodabandeh, the FAO model and geographic information systems (GIS) are used. For this purpose, first the type and degree of major constraints for each land use in the area, including irrigated agriculture, rainfed agriculture, pasture, grazing, tree planting and orchard are identified and then the maps were drawn by GIS. With overlaying the existing layers of the present situation and recommended land use, the final GIS maps were produced on which the proportion degrees of current land use for different types of uses were identified. Afterwards according to the amount and intensity of the main constraints, all land suitability classes per unit are compared for use survival and the best degree of suitability identified. Research results indicate that the largest suggested land use in Khodabandeh area, with the 55 percent of area, is allocated for rainfed agriculture. The pasture and grazing land with an area equal to 21 percent of the area, conservative and arid land with 16% and irrigated agriculture with 8 percent are respectively in the next rankings.

For fulfilling all management and utilization objectives in forest a good access to all parts of the forest is needed via forest roads. Construction of forest roads change forest ecosystem. Negative environmental damages are appeared not only in construction but also inuse of forest road. Some of these environmental damages are includeingdisorder in water flow, increase in river sediments, diminishing habitat of fish and aquatic organisms, soil degradation, decrease in soil productivity, land slide, damage into the forest stand, destructionof natural habitat and extinction of animal species. However, forest road construction is essential for rational utilization, performance of forestry plans and sustainable forest management. Forest roads have a particular sensitivity. Since road depreciation will bring many problems; besides road construction, adequate inspection and conservation should be considered. Attemptsin order to reduction of road damages will get started from planning stage. Forest road planning needs to righ attention and applying advanced techniques is essential for comprehensive study. There are some particular technical notes the paying attention to them can reduce the environmental damages caused by forest roads. This paper expresses some important notes in road planning to reduce the negative environmental damages of forest road.

Erosion and sediment production in its natural state is a complex and multifaceted phenomenon of the various causes interact with each other to create, intensify and reduce it. The study area is located in Daiyer city of Boushehr province. In this research, with quantifying the factors affecting in the erosion based on MPSIACand IRIFR.E.A models the current status of erosion in the area separately assesses and maps related to each of these two methods are also provided. First, work unit map of this region as the base map for evaluating the factors were provided. Then according to the MPSIAC and IRIFER empirical methods¸ water and wind erosion rate is determined at each working unit separately. Further¸ maps of land erodibility for water and wind erosion are prepared using MPSIAC and IRIFER models. Sedimentation potential was measured using the relation between sediment delivery degree and the sediment production. According to the results obtained from this research and comparison of results of the used methods with situation of the area showed that both models have good estimates of water and wind erosion. Finally, results have shown that quantitatively, wind and water erosion contribute to soil erosion and sediment production and soil fertility reduction by 80% and about 20%, respectively.

Natural resources, especially rangelands are considered as sustainable development context of environment and ecological phenomena; they play an effective role in rancher’s life particularly in domesticated animal feed. On one hand, ignoring terms and rules of exploiting by exploiters and on the other hand lack of expert and protector lead to rangelands destruction. Thus, for purpose of studying and prioritizing effective factors on Golestan province ranges demolition in watersheds, experience and views based on experience of natural resources experts have been considered. Questionnaire associated with interview related to the subject of research have been used for collecting data. Questionnaire validity and reliability were attained respectively by specialists’ views and Kronbach alpha coefficient (0.895). Totally 60 questionnaires were filled randomly by experts in province and responses were analyzed by SPSS software after extracting and grouping in Excel. Presented answers for each factor were expressed in variation coefficient way and they were prioritized according to it. Results showed that attributed proportions by experts were different, so the presented priorities were different. In some cases, also, determined grades in both winter- and summer-quarters ranges were considered similar by experts. Totally livelihood and management factors, respectively with the average of 4.14 and 3.84 in winter- and summer-quarters rangelands, from the experts view were known as more effective factors in increasing or decreasing rangelands destruction rather than other factors. Natural factors were introduced as the least effective factor in both winter- and summer-quarters ranges.

This study is an objective effort to investigate the role of wood and paper industries management in application of agricultural wastes and residues. The role of wood and paper industries management of country in sustainable development and upcoming chanlenges (including growing population and over exploitation use of sources especially forest resources, environmental pollutions, importance of sustainable development as an ensuring factor of food safety and generations rights) has discussed in present work. Therefore, the amount of agricultural residues usage in pulp and paper industries in Iran was compared, and in addition to expression of general concepts of sustainable development, following propagative approaches introduced to planners and policymakers of wood industries: training people in optimal use of raw materials, management of agricultural residues and use of these materials in the construction of composite materials, correction of management procedures in forest and waste reduction during operational stage, government support for forest planting of fast growing species, utilization of waste papers through recycling and reprocessing in paper industries, support for NGOs active in environment and recycling, cultural works and public enlightenment to clarify the statues and worth of forest and rangelands and sustainable management.

Given the sensitivity limits to plant growth in pasture lands with saline andalkaline soil, it is necessary to protectthe plants which cause soil conservation against erosion, especially wind erosion, in these lands. In livestock activities that were observed in theselands, the effects of cattle grazing are evident with the factor of distance from the fold. Inthis study therole oflivestockgrazingonsalt tolerantspecieswasstudiedin grazing areas around 3 folds and effects of livestock grazing on vegetation cover in 3 area of different grazing intensity zone were studied based on distance from fold. Results showed although the livestock in that area graze for a long time out of growth season, due toexcessivegrazing,turmoilcan be seen in the vegetation cover. Thedensityof vegetation spotsreduced from 24vegetationspotsinthe areawithoutgrazingto 16/15spotsvegetationwithin thegrazingarea and the size ofvegetation spots reduced from 1680cm in the areawithout grazing to980cm in the area withexcessive grazingareaalong thetransects. Also plantheightofthe vegetation spots declined from 14/23cminrangewithoutgrazing to 14/12cm in the area with excessive grazing.