Effects of nitrogen fertilizer on growth and reflectance characteristics of winter wheat

摘要: A valuable input to crop growth and yield models would be estimates of current condition. If multispectral reflectance indicates condition, then remote sensing may provide an additional tool for assessment. Field experiments were conducted on a typic Argiaquoll at the Purdue Agronomy Farm, West Lafayette, IN determine effects nitrogen fertilization spectral agronomic characteristics winter wheat (Triticum aestivum L). The treatments consisted 0, 60, 120 kg N/ha, applied as urea in spring. Spectral was measured 11 times during 1979 growing season 10 1980 with spectroradiometer (Exotech 20C) 400–2400 nm wavelength region. Agronomic data included total leaf N concentration, chlorophyll stage development, area index, plant moisture, fresh dry phytomass. Relationships between variables developed using from tested 1980. reduced visible, increased near infrared, deceased middle infrared reflectance. These changes related lower levels nonfertilized plots. Green LAI, important descriptor canopies, could reliably estimated data. This study demonstrated that N-stressed distinguished healthy spectrally and, therefore, imagery useful monitoring