نشریه خشک بوم
سال دوازدهم شماره 2 (پاییز و زمستان 1401)

Flooding and soil erosion are a significant issue in the watershed areas of Iran. The result of this is soil lost, soil fertility decreases, vegetation decreases, run-off increases, and severe floods. There are various watershed operations, including biological and mechanical, which protect water and soil, however, it is necessary to investigate which method and how many structures should be used in an area to be more effective. In this research, SWAT hydrological model and scenario building of watershed structures in waterways were used to investigate the impact of watershed management projects on erosion and sedimentation in Sarbaz River watershed, Sistan and Baluchistan province. After preparing the input parameters, the model was recalibrated for a 17-year period (1999-2016) and then validated over a five-year period (2017-2021). The results of the sensitivity analysis showed that the alpha parameters in the return flow and the initial curve number for medium humidity conditions in the SCS method had the greatest effect on the calibration and validation of the simulation. The results obtained from runoff calibration were 0.76 Nash- Sutcliffe coefficient and 0.86 explanation coefficient, and 0.53 and 0.58 respectively for sediment. The scenario's results have regulated the impact of watershed structures on nearly 15% of the sediment. Watershed measures are capable of reducing and controlling runoff, soil erosion, and sediment transfer in the region, as demonstrated by these results. In the meantime, attention should also be given to the financial issues of the plan when selecting watershed scenarios.

To provide quality water for various uses in drinking, health and agricultural sectors, arid regions of our country is facing many challenges. Due to its strategic location and higher sensitivity, drinking water needs better quality. The study area of Bajestan is one of dry lands of Razavi Khorasan province. This city is located in the central area of this area. The agricultural water of this plain is supplied from three Qanats with good quality of the plain, and original resource water for drinking, sanitation and urban green spaces is supplied from the transfer water of playa with lower quality. Since most of groundwater of this area is used in the agricultural sector, this research is aimed at economic analysis of prices, in order to determine the actual price of water input in different uses and compare their ratio. Benefit to cost is done in allocating the type of water source. Considering the population of Bajestan city of 14000 people and daily per capita consumption of 3 liters per person, the daily cost of 42.09 m3 of drinking water is 115441332 IRRs, while the actual daily cost of water in the health sector for this population is 93283042. The results of analysis of costs in the agricultural sector in pomegranate, saffron and pistachio products showed that the ratio of profit to cost is 0.87, 2.2 and 0.89, respectively, which shows that the production of product is not efficient. This is the sector and in the case of raw water sold by farmers to Water Company, even at a third of the actual price of drinking water, that is 914000 IRRs. It leads to a decrease in the aquifer and also to an increase in profit for the smallholder farmers and the management, optimizing water consumption and allocation will help.

The mortality of forest species, especially in arid and semi-arid regions, has been considered the main challenge of diverse ecosystems. The aim of this study is to compare the drying status of Persian oak and Mt. Atlas mastic tree in the Zagros forests in western Iran. To carry out this study, whole forests in the Gilan-e Gharb were considered. For this purpose, the entire surface was divided into equal parts with a sampling grid of 3000 × 3000 m2. The number of 92 sample plots with an area of 0.25 ha were considered for sampling at the intersection of the lines in the forests. Sampling of all the trees in the plots was done 100%. To determine the dryness ratio of the studied trees, based on objective observations, the ratio of the amount of dried branches to the whole tree was used. The results showed that the mean total stock is 39 m3 per hectare. The volume of oak and pistachio species is 34.1 and 8.4 m3/ha, respectively. The living stock of oak and pistachio species is 3.7 and 0.05 m3/ha, respectively, while their dried stock is 13.4 and 4.13 m3/ha, respectively. The highest frequency of dryness includes pistachio with degree 2 (46.94%), and the lowest percentage includes pistachio type with degree 4 (2.9%). The frequency of drying of these species is higher in the initial stages (1 and 2), it decreases in stages 3 and 4, however, in the completely dry state, the abundance of trees increases again. The abundance of fully dried Pistachio is much less than fully dried oak. The analysis results of the frequency variance of drying degrees in oak and Pistachio species show that the frequency of these species has no significant difference with a probability of 95%. The presence of dried pistachio trees with dried Persian oak species needs to be taken seriously, which shows the fragility of these forests.

Today, new patterns of planning at the watershed level have found a valuable place in order to implement collaborative projects. Planning in watersheds with the participation and partnering of regional stakeholders in the process of preparing and implementing plans can be an effective step in increasing the sustainability of the region. Collaborative approaches must be fully aligned with the knowledge, experiences, values, and interests of the various stakeholders. This study is planned with the aim of taking advantage of the perceptions and approaches of the residents of the Mohammad Abad Ganbaki watershed, Kerman, in order to find optimal strategies for the management of the watershed. For this reason, in the upcoming study, it shows the importance and necessity of SWOT analysis to combine the preferences of stakeholders in the decision-making process. For this purpose, the current study has been carried out in three stages, listing the internal (strengths-weaknesses) and external (opportunities and threats), preparing the assessment matrix of internal (IFE) and external (EFE) factors, and preparing the quantitative strategic planning matrix (QSPM). The results showed that the production pole of citrus fruits and dates in the country with a weight of 0.444, the existence of dust centers in the region with a weight of 0.198, the potential of electricity generation from the Nessa Dam with a weight of 0.384 and a one-dimensional economy based on date production with a weight of 0.247 are the most important strengths, weaknesses, opportunities and threats of the region. The high potential of the region in creating early productive commercial workshops according to the existing conditions through the possibility of raising honey bees with the presence of citrus fruits, the possibility of reviving handicrafts, increasing agricultural production and medicinal plants, creating a greenhouse with hydroponic cultivation and fish farming, the possibility of reviving the animal husbandry industry, providing date and citrus packing and processing centers are the most important strategy in the field of providing a job market for young people, reducing economic poverty and migration of residents.

The effects of flood spreading according to soil type and climate on vegetation cover of tree and rangeland species show different changes. The aim of this study was to investigate the periodic changes of vegetation including fruitful and non-fruitful cultivated trees and rangeland species in the Bam Abbarik flood spreading station. In this study, in order to perform forest studies, first the operation of locating the plots, selecting and marking the bases and preparing the certificate was carried out and rectangular parts of 350 square meters with random - systematic distribution were used. Also, in rangeland studies, 1×1 plots were used to measure canopy coved percentage and density and were recorded in the relevant tables. For measuring dry forage production, cut-off and weighing method were used. The results showed that Eucalyptus bases in this aquifer with density of 531 bases in hectare have an average height of 3.62 m and trunk diameter mean at collar site of 18 cm and the crown diameter average 3.6 m. In the study of rangeland cover, the effect of vegetative type, vegetative form, and interaction between vegetative type and vegetative form on crown was significant. Also, the effect of vegetative form, interaction of vegetative type in channel, channel interaction in vegetative form and vegetative form and channel interaction in this experiment were significant on plant density.

In this research, the effects of Haloxylon aphyllum on physical and chemical charactristics of soil considering the age of the plant was studied. The effects of 2, 5 and 10 years old Haloxylon aphyllum at two depths of 0-30 and 30-60 on physical and chemical properties of soil including total nitrogen, total phosphorus, total potassium, soil organic carbon, soil texture, pH, electrical conductivity and carbon-to-nitrogen ratio of soil were evaluated. In this research, 30 soil samples from underneath of Haloxylon aphyllum (10 samples for each age and 5 samples for each depth) and 30 samples between the plants were taken and their physicochemical and chemical properties were measured in the laboratory. Then, the data were analyzed using ANOVA and Mann-Whitney tests in SPSS software. The results showed that planting of Haloxylon aphyllum and its age at two studty depths have a significant effect on pH, but has no significant effect on EC. There was no significant difference between the soil texture in the experimental area and the control area, but the amount of sand and silt just for biennial shrubs in both soil depths had significant change. The implantation of Haloxylon aphyllum on N and OC at 0-30 depth has a significant effect, but does not affect the depth of 30-60 cm, but the age of the Haloxylon aphyllum in both depths has a significant effect on N and OC content. Vegetative planting in both depths of 0-30 and 30-60 was not significantly affected by P, K and C/N variables, and the age of the plant in both depths was significant on K soil and at 0-30 with P soil. In general, the results of this study showed that the effect of age on the change in chemical properties of soil is significant and with increasing age of the site (the age of Haloxylon aphyllum grafts) this effect is more evident.

The implementation of combating desertification projects can not be considered apart from their socio-economic impacts. In recent years, many combating desertification projects such as mulching, planting resistant species and etc., have been implemented in the country. Many combating desertification projects have been implemented in Yazd province, including Meybod-Ashkezar. The purpose of this research is to investigate the impact of the implementation of combating desertification projects from the peoples’ point of view. To conduct the present research, the sample size was calculated using Cochran’s method, 286 samples. The questionnaire was designed based on the five-choice Likert scale and several items including 6 economic items, 5 social items and 7 management items were considered in the questionnaire and were randomly completed by people. Then, the priority of each item was checked using Friedman’s non-parametric test. The research results showed that the economic criteria, the effect of the implementation of afforestation and Meybod wind canal projects, reducing damage to agricultural lands and products with an average rating of 4.82, was placed as the first priority of people’s evaluation. In the next ranks, the reduction of damage to residential and industrial lands and the increase of agricultural and horticultural production per unit area were evaluated with an average 4.06 and 3.77, respectively. Regarding the people’s attitude towards the plan, the results showed that the people’s willingness to participate in the maintenance of the plan with an average rating of 3.30 is the first priority. Regarding the Peoples’ point of view to projects, the results showed that the people’s willingness to participate in the maintenance of the plan with an average rating of 3.30 is the first priority. Regarding the management criteria, reducing the influx of sands, reducing the production of dust and local storms, and Reduction of agricultural crop pests with average 5.52, 5.37, and 4.43 were placed in the next priority of public evaluation. Therefore, the positive effect of desertification projects has been well felt by the residents of the region, and it is appropriate to take measures to bring closer the officials of this sector and the local community for the purpose of better protection of natural resources.

Organic agriculture is an integrated farming system, based on natural principles and laws, where the quality of products is more important than their quantity. Therefore, the present study was conducted in order to investigate the effect of two types of biological and organic fertilizers on the growth and yield of two types of beans under drought stress in the research farm of Shahrekord University. The experiment was carried out in the form of split split plots in the form of a completely randomized block design, and in three replications. The investigated factors include 1- drought stress at three levels of 60, 90 and 120 mm of evaporation from the surface of the class A pan and the second factor at four levels: EM biological fertilizer, Vinas organic fertilizer, a combination of both, and control; and the third factor: species of two levels (Mexican yam beans, red beans of the flower variety). In this experiment, the traits of plant height, number of secondary branches, relative humidity of leaf water, cell membrane stability index, number of pods per plant, biological yield, seed yield and harvest index were measured. The results of variance analysis of the data showed that the effect of the studied factors and their interaction (except for the interaction of stress × fertilizer on the number of pods per plant and cell membrane stability index) was significant on all traits. The results showed that the combined fertilizer treatment (vinas + EM) in red bean plant and stress 60 had the greatest effect on the characteristics of seed yield (8834 kg/ha), harvest index (64.66%), plant height (117 cm), the number of pods per plant was (32.33), and the number of sub-branches (14). In the same fertilizer treatment and in the control stress treatment, the greatest effect was on the trait of cell membrane stability index in red bean plant (57.7%) and relative humidity. Leaf water (91.88%) and biological yield (35710 kg/ha) were in Mexican yam plant. Generaly, it can be said that this experiment showed the superiority of combined fertilizer treatment on red bean plant under drought stress compared to Mexican yam plant.