جستجوی مقالات مرتبط با کلیدواژه "آزمون تحلیل روند" در نشریات گروه "کشاورزی"

The present study was conducted to investigate NPP changes and its relationship with drought. The monthly time series of NPP for the country's rangelands was prepared from the sum of net photosynthesis production (PSN) of the eight-day MODIS sensor (MOD17A2H) with a spatial scale of 500 m for 2000 to 2022.The monthly rainfall data of 165 synoptic stations were obtained from the National Meteorological Organization to calculate the Standard Precipitation Index (SPI) and monitor droughts in this period. Box plots of precipitation and NPP were prepared and showed that the highest values of NPP with an average of more than 50 gC.m-2month-1 occur during spring and early summer in humid areas. Results showed that NPP is increasing in Iran's rangeland ecosystems, and on average, the NPP of all rangeland ecosystems in the country is about 112.6 ± 13 gC.m-2.year-1  ,in other words, about 76 million tons of carbon per year. It is absorbed by the plants in the rangeland ecosystems of the country. The trend of changes in the monthly series of NPP was not significant due to the influence of seasonal characteristics, but the annual changes of NPP showed a significant trend of increase in all regions.

One of the methods for optimal use of water resources in critical conditions of groundwater and surface water resources is the implementation of artificial recharge projects. These systems aim to store excess surface water in groundwater reservoirs in order to improve the quantity and quality of water in different soil layers. The purpose of this research is to investigate the impact of artificial recharge on the quality and quantity of groundwater resources in the Shamil-Ashkara plain. For this purpose, water table fluctuations and electrical conductivity (EC) changes of the wells affected by the artificial recharge project have been investigated spatially and temporally using trend analysis tests. The results showed that the studied observed wells in the plain have a decreasing trend in their ground water level, so that on average, during the studied period, the water level declined by 0.41 meters per year, and in general, the water level decreased by 11.7 meters. However, the effect of artificial recharge on the changes of the surrounding wells can be seen and at one point in time, it caused an increase and compensation of 9.6% of the tank drop, and also the EC level has reached from 4500 ds/m to 4000. But after two years, artificial recharge ponds have lost their effectiveness. This issue requires frequent monitoring and maintenance of the effectiveness of artificial recharge plans.

A Groundwater resource is one of the most important sources that provide agriculture, domestic and industrial demand. The aim of this study is trend analysis of quantity – quantity groundwater fluctuations in the Minab plain from Hormozgan province. In order to assessment quantity and quality fluctuations was used Groundwater Resource Index (GRI) in the time period 1968- 2015 and EC, pH, SAR, TH in the time period 2008-2015, respectively. IDW method was used to map zoning of quality characteristics in ArcMap software. Mann- Kendal trend test used to analyze groundwater level oscillation. Result showed that groundwater level have decreasingly trend in the seasonal and annual time scale. As, Mann- Kendal Statistic is strong in the East and Southern plain. Iso- hyetal groundwater quality map showed that much of area (0.63%) has suitable water quality and the central of plain (0.37%) has unsuitable water quality.