John Winings¹, Xinhua Yin¹, Agyin-Birikorang Sampson², and Upendra Singh²

¹ The University of Tennessee

² International Fertilizer Development Center

Environmentally and economically sustainable agriculture calls for reduced fertilizer consumption and increased nutrient use efficiency. Organically enhanced biofertilizer Unity NPSFe manufactured from sterilized organic additives extracted from municipal wastewater biosolids and NPKZn briquettes of approximately 2.43 grams in weight per briquette were evaluated for grain yield and quality of non-irrigated corn relative to conventional N fertilizers ammonium sulfate and urea from 2011 to 2013 at Jackson and the Ames Plantation in Tennessee on silt loam soils. The following measurements were taken during the season: soil NH₄-N, NO₃-N, extractable P, K, S, and organic matter content; viable biomass, community structure, and metabolic activity of soil microbes; plant height, plant biomass, and grain yield; N, P, K, S, Zn, and Fe concentrations in plant biomass and grain; kernels/plant, mass/kernel, and ear length; and corn ear health quantified by physiological disorder, disease infection, and insect attack ratings. After harvest, briquettes produced the least amount of residual soil NO3-N followed by Unity biofertilizer.  Unity biofertilizer and briquettes did not significantly differ from ammonium sulfate or urea in grain yield across years and locations.  Grain nutrient concentrations differed significantly among the treatments for N, P, K, and S but not Fe.  Unity biofertilizer and urea produced the highest N corn grain concentration; whereas, the briquettes and ammonium sulfate produced the highest P and K corn grain concentrations, and Unity and ammonium sulfate produced the highest S corn grain concentrations.  Corn ear health only differed significantly among the treatment types under physiological disorder ratings and only within the 170 and 85 kg N ha^-1 treatment rates.  Under the 170 kg N ha^-1 treatment rate urea had 60 percent of the worst corn ear physiological disorder while Unity biofertilizer was the only treatment that had no corn ears in the worst two physiological disorder ratings.  Our results suggest that Unity biofertilizer could be a preferred fertilizer source because it produces comparable grain yields and quality with higher nutrient use efficiency than either urea or ammonium sulfate while supplying P in addition to N.

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