Organic Matter Composition of Manure and Its Potential Impact on Plant Growth

Abstract

Since the advent of flush toilet systems, the aquatic environment has received a massive contaminant flow. Furthermore, the perception of human feces has changed from a useful nutrient source for agriculture to a harmful contaminant. In this study, we compared the nutritional quality of five samples: (1) human manure (HM), (2) human manure from a family mainly eating organic food (HMO), (3) cow manure (CM), (4) poultry manure (PM), and (5) commercial nursery media (CNM). Samples were analyzed in terms of organic and inorganic nutrient contents, molecular composition, seed germination, and chlorophyll concentration. Pyrolysis gas chromatography/mass spectrometry (GC/MS) was used to describe the differences in molecular composition. Three-dimensional excitation and emission matrix fluorescence spectroscopy characterized the organic composition of water extracts. From the results, CNM, PM, and HMO showed humic- and fluvic-like substance peaks, the highest values of potassium and sulfate ions, and of C/N ratios, indicating greater plant growth potential. This was confirmed by their higher chlorophyll concentrations and germination index values. These results contribute knowledge about the positive effects of manure, changing the negative perception of human excreta from waste to resource. This work provides a reference for reducing the wastewater loading rate in society.