مجله ترویج و توسعه آبخیزداری
پیاپی 26 (پاییز 1398)

Droughts are one of the most common climate changes that surround many arid and semi-arid regions of the world with high intensity every few years. Based on previous studies, the SPI index is one of the most widely used indices for surveying. Meteorological droughts in the world and in Iran. It is also a critical drought that has greatly affected the arid areas, especially the Yazd province. In this research, the characteristics of drought phenomenon such as intensity and continuity at the province level were determined and analyzed. The results of drought severity analysis in Yazd province indicate that the most severe droughts occurred in the year 1998-1999. The results show that the highest drought persistence for 8 years is related to Yazd (stations of Yazd P centers of and Mohammad Abad) and then Bafgh city with duration of 7 years (stations of Qotomr, Koushk). The most frequent drought persistence in the province was 2 and 3 years old

Edible parts of some agricultural products are inside the soil, and some soil is then displaced when these products are harvested. This displaced or detached soil, damages the land i.e. reducing its fertility and soil quality, as well as significant health, environmental and economic consequences in different stages of the production to consumption chains, such as in time of delivering to plants factories and processing. In soil conservation science, this phenomenon is called harvesting erosion because the soil is removed from its original location and no longer comes back. Among the various processes of soil erosion that threaten sustainable agriculture, there is not much information about soil loss due to crop harvesting (SLCH) of roots, tubers, and onions of agricultural products. Since this important neglected issue is a common point of many agricultural specialties, such as soil and water conservation, watershed management, and post-harvest issues; this paper focuses on the importance and determinants factors of the occurrence and reduction of this phenomenon

Predicted rainfall and temperature is one of the most important issues in the planning and management of water resources. To use General Circulation Models GCM models in the study of water resources, it is necessary to use different methods to make them as small scale. In this study, The SDSM model was run using outputs of Hadcm3 models. Based on the results of downscaling data of SDSM model two climatic parameters in three period of 20 years under scenarios A2 and B2 of the Hadcm3 model, were evaluated for Birjand synoptic stations. Based on the results, the temperature values are more correlated to observe data were compared with Rainfall amounts that is in The period of 2029-2010, 2059-2030 and 2080-2060 by Scenario A2, Average temperature, respectively, 5.82, 8.41 and 14.56 percent and according to scenario B2, respectively, 4.08, 9.06 and 11.42 percent, Increase compared to the baseline Birjand synoptic station. And the amount of annual rainfall for the three scenarios studied by A2, respectively, +1.46, -2.27 and -8.66 percent compared to the baseline will change. In a given period based on the B2 scenario will also reduce the amount of rainfall

 Desertification means the destruction of land in arid, semi-arid and semi-humid regions, which are caused by various factors such as climate change and human activities. In this research, the performance of comprehensive desertification plans Including forests management, seedling, runoff management, care and irrigation, conservation, and planting of seedlings in 21 provinces of the country were analyzed using Morris model. The Morris model is the newest formal model for grading areas in terms of development (physical and human) on a global scale and is applicable for planning with different and varied scales. The results showed that the provinces of Khorasan Razavi, Isfahan, South Khorasan, Kerman, Sistan and Baluchestan, Semnan and Khouzestan with the development coefficient (DI) respectively 41.5, 40.07, 38.60, 37.28, 36.72, 32.90 and 30.42 has good condition and acceptable performance, Markazi provinces and Yazd, with the development index respectively 28.36 and 23.48 were in the middle condition, Tehran provinces, Hormozgan, Bushehr, Fars, North Khorasan, Ilam, Qom, Qazvin, West Azarbaijan, Alborz, Golestan and Hamedan with the development coefficient (DI) with the development index (DI) respectively 12.61, 10.79, 9.88, 8.96, 8.71, 5.23, 4.24, 2.50, 0.92 and 0.68 has poorly performance in studied projects. At the end, the results of the study were prepared in the form of a table and the development coefficient map of the evaluated provinces in this paper was prepared using the performance of each province from the above-mentioned plans to deal with the desertification phenomenon in the Arc GIS environment.The results of this study can be used in decision making on the performance of provinces in the country against desertification phenomena. By utilizing more comprehensive desertification plans such as seedlings, planting forests and conservation and protection, desertification can be reduced in the country.

 Regarding the problems created for the Urmia Lake basin, which is mainly due to the lack of integrated water resources management in this basin, it is necessary to conduct studies with respect to agricultural water consumption management approach. In this research, using the available statistics on the production and consumption of crops and gardens, as well as the export and import of these commodities in the Urmia lake basin, the amount of exchange with regard to the virtual water of each product was determined. Given the crop water requirement of each plant and its yield, the amount of water used to produce the final product was determined, and then, with regard to the export and import data of each product, the figures for the water trade of the basin were identified. During the study period (2008-2012), in average, sugar beet (by devoting 394 MCM) and berries (by devoting 0.001 MCM) have highest and lowest virtual water export, respectively. In contrast, rice (by devoting 936.1 MCM) and sumac (by devoting 0.003 MCM) have highest and lowest virtual water import, respectively. Over the studied years, 9.7 MCM of virtual water were imported to the basin. Based on the results, it is also proposed to reduce the export of products such as sugar beet and onion and instead, by importing these products it could be possible to save the water. Therefore, with the presented method in this paper, the possibility of restoring water resources in a basin can be assessed through virtual water management.

With due attention drought and water deficit in recent years, artificial recharge (A.R.) projects have been special importance as a solution execute for comparison with present state. A.R. projects effect on environmental, social and economic dimensions through direct or non-direct. This efficient can sustainable or non-sustainable for development dimensions. First, sustainability development of A.R. projects need appointment and description assessment framework. One of the effect framework for sustainability assessment of environmental, social and economic is DPSIR framework or driving force-pressure-state-impact-response. In this search, assessment criteria and indicators appoint with DPSIR framework, area condition, special view to A.R. project of Kal (south of Fars province) and notice area environmental, social and economic problems. Research method is questionnaire- analytic method. This research be based on Delphi method and asked from 16 experts. Results show, 10 criteria appoint for environmental, social and economic dimensions. Also, 100 indicators appoint for three dimensions. For environmental dimension (with 4 criteria) 54 indicators, social dimension (with 3 criteria) 27 indicators and economic dimension (with 3 criteria) 28 indicators

 An important part of water resulted from the country's rainfall, especially in arid and semi-arid areas, is losted through evaporation from the soil surface. In this regard, the use of mulches or amendments, in addition to improving soil properties, can reduce water losses deu to evaporation. Towards this, the purpose of this study was to compare the effect of two organic and polymer amendments on evaporation of water from soil surface under laboratory conditions. To this end, a factorial split plot experiment was planned in a completely randomized design and two amendments of vinasse and A12 polymer were applied at four concentrations of 20, 25, 33 and 50% of initial concentration with control and three replications on the loess soil samples belong to dry land of Kalaleh - Gorgan Province. The screened soil was poured into equal amounts of 27 pots and the pots were irrigated with 50 ml. After enough time to reach initial equilibrium, the treatments were added to the pots with a volume of 10 ml. Each of the pots was weighed accurately and this job continued on a constant time every day as long as the weight of each pot reaches the initial weight before adding the initial moisture and treatment. Finally, the results of the experiments analyzed in a completely randomized design and their averages were compared with Duncan’s method. The results showed that the effect of treatment, day, concentrations of treatment and interaction between days and treatments and concentrations of treatment and days was significant at 5% probability level on evaporation rate. Overall results showed that the difference between the two treatments of vinasse and polymer on evaporation was significant and both on average 0.20 and 0.01 mm respectively (3.3 and 0.15% respectively) were effective in decreasing evaporation rate compared to control.