The Use of Hyperspectral Proximal Sensing to Determine Moisture and Nutrient Content of Dung Pats in the Field.

The estimation of nutrient return to grazed ecosystems is of great importance in modeling the movement of carbon, moisture, and nutrients in the system. However, nutrient and moisture content of as-deposited dung pats varies widely between individual animals and can be influenced by forage type, forage quality, time of season and weather. Physical sampling and laboratory analysis of large numbers of dung pats is unrealistic due to the time and costs involved. This study evaluated the use of a backpack-mounted hyperspectral sensor for predicting age of dung, moisture content, and nutrient content of unaltered dung pats in the field. Results showed good correlation with spectral response and nitrogen and phosphorus contents, moisture, and age of dung. There was poor correlation between spectral reflectance and total organic carbon, nitrate, and ammonium. Hyperspectral spectroscopy shows promise as a non-destructive method to evaluate nutrient content of dung and to help model nutrient movement from dung through the environment over time.