Yonca (Medicago sativa L.)’da Uzaktan Algılama Yöntemi İle Azot Düzeylerinin Tahmin Edilebilirliği

Abstract

The aim of this study was to obtain spectral reflectance values by using remote sensing method in alfalfa plant and to estimate nitrogen levels by using these values. The treatments were carried out in both field and greenhouse conditions. Different nitrogen, phosphorus and potassium doses were applied to plots in the field and pots in greenhouse. Spectral reflectance measurements were made at both the canopy (general) level and the single leaf level when the plants were in pre-flowering stage. Reflectance measurements were undertaken using a portable spectroradiometer measuring the wavelength range of 325-1075 nm of the electromagnetic spectrum. Plant probe with artificial light source and leaf clip were used for leaf measurements. Statistical analyses were conducted using stepwise regression analysis implemented in MINITAB-13 statistical program. As a result of the study, significant relationships (Field-canopy: 0.94, Field-leaf: 0.23, Greenhouse-canopy: 0.55, Greenhouse-leaf: 0.92) were determined between the nitrogen levels in the plant and the reflectance values. Also results showed that changes in nitrogen levels affect reflectance in the visible region (400-700 nm) of the spectrum. When the wavelengths were evaluated separately, it was observed that the wavelengths of the blue, red and near infrared regions, which are important for photosynthesis, can be used to estimate the nitrogen levels.