EVALUATION OF A LIQUID POTASSIUM BICARBONATE AMINO-ACID CO-PRODUCT ASA SOURCE OF POTASSIUM, NITROGEN, AND SULFUR

Potassium bicarbonate (KHCO3), methionine, alanine, and other organic sulfur (S) compounds are present in a liquid co-product (DPF for Degus sa's Potassium Fertilizer) resulting from the manufacture of methionin e as a poultry feed supplement. DPF contains approximately 20, 97, and up to 30 g/kg of nitrogen (N), potassium (K), and S, respectively. Fi eld, greenhouse, and incubation studies were conducted to evaluate cro p response to N and K in DPF as compared to ammonium nitrate (NH4NO3) and potassium chloride (KCl), to determine mineralization of N and S i n DPF and to determine any potentially phytotoxic effects of high rate s of DPF in sandy soils of the Gulf Coastal Plain. In both field and g reenhouse 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 3 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 ma tter yield of sorghum-sudangrass [(Sorghum srndanense (Piper) Stapf] i n greenhouse studies, apparently as a result of excessive salts in the soil.