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Evaluation of Soil Degradation Based on High Resolution Remote Sensing Data
145-148Views:77Soil salinity is the main problem of soil degradation in the Grate Plain with cultivated area of 20% affected. Its influence is accelerated on the water managed and irrigated lands. Remote sensing can significantly contribute to detecting temporal changes of salt-related surface features. We have chosen a farm where intensive crop cultivation takes place as a test site as soil degradation can be intensive as a result of land use and irrigation. In order to evaluate soil salt content and biomass analysis, we gathered detailed data from an 100x250 m area. We analyzed the salinity property of the samples. In our research we used a TETRACAM ADC multispectral camera to take high resolution images (0,2-0,5 m) of low altitude (300-500 m). A Normalized Vegetation Index was computed from near infrared (750-950 nm) and red (620-750 nm) bands. This data was compared with the samples of investigated area. Analyzing the images, we evaluated image reliability, and the connection between the bands and the soil properties (pH, salt content). A strong correlation observed between NDVI and soil salinity (EC) makes the multispectral images suitable for construction of salinity map. A further strong correlation was determined between NDVI and yield.
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Usage of Different Spectral Bands in Agricultural Environmental Protection
123-126Views:82Hyper and multispectral imaging systems are widely used in agricultural and environmental protection. Remote sensing techniques are suitable for evaluating environmental protection hazarsd, as well as for agriculture resource exploration. In our research we compared aerial hyper and multispectral images, as well as multispectral digital camera images with the background data from the test site. Hyperspectral records were obtained using a new 80-channeled aerial spectrometer (Digital Airborne Imaging Spectrometer /DAIS 7915/. We have chosen two farms where intensive crop cultivation takes place, as test sites, so soil degradation and spreading of weeds can be intensive as a result of land use and irrigation. We took additional images of air and ground with a TETRACAM ADC wide band multispectral camera, which can sense blue, green and near infrared bands. We had detailed GIS database about the test site. Weed and vegetation map of the area in the spring and the summer was made in 2002. For soil salt content analysis, we gathered detailed data frome an 80x100 m area. When analyzing the images, we evaluated image reliability, and the connection between the bands and the soil type, pH and salt content, and weed mapping. In the case of hyperspectral images, our aim was to choose and analyze the appropriate band combinations. With a TETRACAM ADC camera, we made images at different times, and we calculated canopy, NDVI and SAVI indexes. Using the background data mentioned above, the aim of our study was to develop a spectral library, which can be used to analyze the environmental effects of agricultural land use.
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Applicability of precision weed detection technologies
163-168Views:157In an agricultural field or horticultural plantation, weeds compete with cultivated plants for water and nutrients. The transpirated water by the weeds is needed to be replaced, which saddles surplus costs on the farmer, which could reduce the profitability of crop production. The aim of the precision plant protection system is to protect cultivated plants by applying site-specific technologies and optimized herbicides combination and methods, without environmental damage. The first step of precision weed control is the scouting for weeds. Traditional and modern (passive and active remote sensing) weed surveying technologies are available to detect weeds. The examination was carried out in an intensive apple orchard with drip irrigation system, protected by hail net of the Study and Regional Research Farm of the University of Debrecen near Pallag. The spectral-based weed detection was worked out by the Tetracam ADC broadband multispectral camera and the GreenSeeker 505 vegetation indexmeter. A strong correlation observed between vegetation indices and weed coverage. Based on the collected data, weed maps are created in appropriate software environment, thus the spatial distributions of the weeds are determined. The species level discrimination and the recognition of weed structural parameters were executed based on the 3D point cloud data by Leica ScanStation C10 laser scanner.