Evaluation of a liquid potassium bicarbonate/amino acid co‐product as a source of potassium, nitrogen, and sulfur

Abstract

Potassium bicarbonate (KHCO₃), methionine, alanine, and other organic sulfur (S) compounds are present in a liquid co‐product (DPF for Degussa's Potassium Fertilizer) resulting from the manufacture of methionine as a poultry feed supplement. DPF contains approximately 20, 97, and up to 30 g/kg of nitrogen (N), potassium (K), and S, respectively. Field, greenhouse, and incubation studies were conducted to evaluate crop response to N and K in DPF as compared to ammonium nitrate (NH₄NO₃) and potassium chloride (KCl), to determine mineralization of N and S in DPF and to determine any potentially phytotoxic effects of high rates of DPF in sandy soils of the Gulf Coastal Plain. In both field and greenhouse studies using four different crops, plant dry matter, grain yield, and N and K uptake with DPF were equivalent to comparable rates of N and K as NH₄NO₃ and KCl. Nitrogen and S in DPF, methionine, and ground cotton (Gossypium hirsutum L.) leaves were mineralized by soil microorganisms at similar rates. Very high DPF rates (5700 kg/ha or 2.5 g/kg) had no adverse effect on crops in the field but reduced dry matter yield of sorghum‐sudangrass [(Sorghum srndanense (Piper) Stapf] in greenhouse studies, apparently as a result of excessive salts in the soil.