Determination of Plant Phosphorus Nutritional Status Using Spectral Response

Abstract

Sensor - based methods of determining the phosphorus (P) status of plants have not been developed. The objective of this research was to determine the feasibility of measuring in-situ P levels in winter wheat (Triticum aestivum L.) using spectral data. Spectral irradiance measurements were taken and investigated from wheat that was grown with different nitrogen (N) and P rates on a soil low in soil test P. Total P in wheat plant tissue and forage P uptake were correlated with various wavelengths but not always consistent across growth stages or years. However, there was some consistency for correlation between P tissue concentration and spectral irradiance from wavelengths 705 - 725 (numerators) to 505 - 515 (denominators). Grain yield was correlated with spectral irradiance readings near 755 nm using the UV light at night for both years from Feekes growth stages 4 through 7. Improvements in data collection and data processing need to be addressed for further research.