فهرست مطالب علی نظمی

The study aimed to compare the catch composition, CPUE, and CPUA of dominant commercial fishes caught by bottom trawl nets (Plan approved by the Fisheries Organization) in different depth layers of The Gulf of Oman,Sistan and Baluchistan Province. This study was carried out during 2 sampling stages in September and March 2018 (fishing seasons). Fishing operations were carried out periodically in layers of 50 meters, 50 to 100 meters, and above 100 meters by the Avash industrial trawler equipped with a bottom trawl net with a power of 2250 horsepower in 24 designated stations (4 times of net hauling per day in 6 days). Based on the calculated CPUE and CPUA results in the first stage, a significant difference was observed between the CPUE and CPUA amounts of John's snapper in the first and second depth layers, and between the CPUE and CPUA amounts of Cobia in the first and third depth layers (P<0.05). Javelin grunter (CPUE: 99.9±45 and CPUA: 2122.6±1132.2) in the first depth layer, black pomfret (CPUE: 53.6±28.7 and CPUA: 738.2±407) in the second deep layer, and longrakered trevally (CPUE: 89.9±40.2 and CPUA: 1181.6±515.7) in the third deep layer had the highest amount of CPUE and CPUA. In the second fishing stage, there was a significant difference between the amount of CPUE and CPUA of the Javelin grunter, Talang queenfish, and Cobia in the second and third depth layers (P<0.05). Javelin grunter (CPUE: 71.2±21.1 and CPUA: 1230.9±428.6) in the second depth layer and longrakered trevally (CPUE: 44.5±9.9 and CPUA: 596.2±129.3) in the third depth layer had the highest amount of CPUE and CPUA. Based on the obtained results, the highest amount of CPUE and CPUA were estimated in the first, third, and second depth layers in the first sampling stage, and in the second and third depth layers in the second sampling stage, respectively.

The main objective of this quantitative-qualitative research was to analyzing the mental preferences of paddy farmers towards second cultivation in Rasht County. The statistical population of the study consisted of 30 progressive farmers in Rasht County who were selected by purposive sampling technique. The collected data were analyzed by SPSS22 and Expert Choice11 softwares. The reliability and Validity of the questionnaire was approved by calculating the Cronbach's alpha and construct validity.The Findings showed that "lack of government support for the production and sale of these products, lack of successful model farms in cultivating alternative crops under government management" and "lack of an appropriate market for these products» with a ratio of 93, 90 and 73%, were the most important barriers to farmers' willingness to second cultivation, respectively. Also, the most important factors determining the type of cultivation were revenue generation, production costs and market for products, respectively. The results showed that, ratoon and local beans were in the highest ranks in the farmers' mental preferences in growing crops based on revenue generation, sales and production cost criteria, but in terms of water scarcity and employment criteria, local beans and forage were in the highest ranks, respectively. Overall, the results showed that, ratoon with a weight value above 0.453 was in the first priority in second cropping pattern and local beans and forage (with 0.353 and 0.087 weights) were in the next priorities, respectively. Designing an optimal cropping pattern, guaranteed purchase, establishing model farms and development of conversion industries are suggested.

Water is the main factor in forest production and rain and snow are the most important sources of forest water supply. But always a percentage of rainfall is lost and comes out of the forest surface water cycle. That part of the rain that does not reach the soil of forest ecosystems is divided into two parts. This article reviews the concept of rainfall in the forest and the impact of its components on the water balance of watersheds. Rainfall of trees plays an effective role in determining the amount of rainfall reaching the forest floor and therefore is an important part of the water level in the ecosystem of forest structures. Loss from the canopy surface and evaporation from the forest floor debris. It also focuses on the hydrological cycle and the food cycle in terrestrial ecosystems. If you know the amount of rainfall in areas with dry season during the growing season, if the amount of rainfall is high, according to the water needs of the mass, by performing thinning operations, to establish regeneration and also to meet the water needs of species The plant helped effectively. A large share of summer rainfall in the forest in the form of rainfall is out of reach of the forest massif; Therefore, it is necessary to know the amount of rainfall, especially to evaluate and measure evapotranspiration in forest ecosystems and therefore for the proper management of forest watersheds.