The use of remote sensing images in the monitoring of drought is a great advantage in detecting the effects of drought on vegetation, since it enables measurement and observation in the time series. The growth and development of selected crop, maize, was monitored with the high-resolution satellite imagery Sentinel-2. Selected research area were agricultural lands in Murska Sobota between years 2016 and 2017. By calculating the NDVI vegetation index, we wanted to find out, whether we can observe the changes in maize crop that was exposed to various biotic and abiotic stress. At the same time, we wanted to determine if the visual condition of the crop differs from that of the estimated satellite imagery. The study includes fields covered with maize on both heavy and light soils. One part of the fields was irrigated, while the second part was exposed to natural precipitation. The results showed that the NDVI index has detected when vegetation is in water stress. In reality, this is expressed as yellowing and drying of leaves. In the initial signs of water scarcity, the condition of plants in the field is different from the satellite imagery. At the peak of the growing season the NDVI index on irrigated soils is statistically higher than on non-irrigated. Thus, the irrigation has an impact on increasing the index, which reflects vegetation in better condition. Compared to the impact of the soil texture on the index values, heavy soils can retain water for longer periods of time. This results in better vegetation during the accelerated growth and leaf development phase. At the end of the vegetation period, the statistical analysis shows larger index for light soils compared to the heavy ones, which coincides with the highest yields on irrigated light soils.
|
