جستجوی مقالات مرتبط با کلیدواژه "satellite imagery" در نشریات گروه "مکانیزاسیون کشاورزی"

Wind erosion is one of the most important desertification processes in arid and semi-arid regions. This process destroys lands, soil, water resources and more. Dust phenomenon is one of the most important consequences of wind erosion in Iran and worldwide and especially in the west and southwest of Iran. Therefore, the present study is based on a combination of field data, remote sensing, and climatology and physiography data, In order to identify internal dust generating centers in the western part of the country. Based on the statistical results, the maximum dust event was recorded for the study area during 2008, 2009 and 2012. On a monthly basis, May, June and July are the most dusty events. On an hourly scale, the maximum occurrence of dust occurs from 9 am to 6 pm local time. Tracing of inlet dust paths showed that during the warm period of the year most of the input dusts are in the northwest - southeast and west - east direction and in the cold period especially late in the south - north direction of the study area. Land use mapping and surveying changes indicate a decrease in water levels, vegetation cover, and land depletion in 2015 compared to 2000. These features, along with physiographic features such as high erosivity of the formations, presence of saline and marshy soils, low soil moisture, high variability of land use, identified potential areas and potential for dust generation in the target provinces.

Local information about tillage intensity and ground residue coverage is useful for policies in agricultural extension، tillage implement design and upgrading management methods. The current methods for assessing crop residue coverage and tillage intensity such as residue weighing methods، line-transect and photo comparison methods are tedious and time-consuming. The present study was devoted to investigate accurate methods for monitoring residue management and tillage practices. The satellite imagery technique was used as a rapid and spatially explicit method for delineating crop residue coverage and as an estimator of conservation tillage adoption and intensity. The potential of multispectral high-spatial resolution WorldView-2 local data was evaluated using the total of eleven satellite spectral indices and Linear Spectral Unmixing Analysis (LSUA). The total of ninety locations was selected for this study and for each location the residue coverage was measured by the image processing method and recorded as ground control. The output of indices and LSUA method were individually correlated to the control and the relevant R2 was calculated. Results indicated that crop residue cover was related to IPVI، RVI1، RVI2 and GNDVI spectral indices and satisfactory correlations were established (0. 74 - 0. 81). The crop residue coverage estimated from the LSUA approach was found to be correlated with the ground residue data (0. 75). Two effective indices named as Infrared Percentage Vegetation Index (IPVI) and Ratio Vegetation Index (RVI) with maximum R2 were considered for classification of tillage intensity. Results indicated that the classification accuracy with IPVI and RVI indices in different conditions varied from 78-100 percent and therefore in good agreement with ground measurement، observations and field records.