Affiliation:
1. Slovak University of Agriculture in Nitra, Faculty of Horticulture and Landscape engineering, Institute of Landscape Engineering
Abstract
Using remote sensing functional aspects of the landscape such as energy exchange between vegetation and the atmosphere, surface reflectance or vegetation heat flux can be monitored and evaluated in detail. Multispectral imagery is used to obtain information on the condition of the vegetation and plant growth, as it allows us to obtain information on possible nutrient deficiencies, pest damage or other manifestations of abiotic stress on the plants. Each surface reflects and emits radiation at different wavelengths, making it possible to create spectral curves for each surface. The waveforms of spectral curves differ based on vegetation type or physiological state, they exhibit similar basic features. Vegetation indices are used to process the measured data. In our research we focused on the changes in the values of selected vegetation indices depending on soil moisture. Spectrometer measurements were only made in 2021 on walnut in the irrigated and non-irrigated variants. The Normalized Difference Vegetation Index (NDVI) index is influenced by the chlorophyll content of the leaves. The NDVI value increased after application of irrigation dose. In the non-irrigated variant, the values decreased with decreasing rainfall and at the beginning of August. Measurements of vegetation indices show better canopy physiology in irrigated trees that responded to changes in soil moisture. Leaf physiological condition in the nonirrigated variant was more variable. As a result of the rainfall between 12 July and 27 July, when a total of 18.7 mm of rainfall fell, the condition of the non-irrigated trees began to improve.