Field Evaluation of Acid-Base Fertilizers on Spring Wheat

This study was initiated to evaluate acid-base fertilizers on highly calcareous soils in the Red River Valley area of Minnesota and North Dakota. These soils represent an environment where acid-base materials might provide additional flexibility in soil fertility programs because of their proposed ability to produce an acid environment in the zone of application. Two field experiments were conducted during the 1981,1982, and 1983 growing seasons to make this evaluation. One experiment utilized seed placements (band) and the other broadcast placements (surface). All experiments were conducted with spring wheat (Triticum aestivum L.) as the test crop on a Hegne silty clay soil (fine, frigid Typic Calciaquoll). Urea phosphate (UP), diammonium phosphate (DAP), UP combined with urea-ammonium nitrate solution (UAN), and ammonium polyphosphate (AP) combined with UAN were utilized in the seed placement experiment, each at two rates (22 to 26 kg N ha⁻¹ and 25 kg P ha⁻¹ at the low rate and 44 to 52 kg N ha⁻¹ and 50 kg P ha⁻¹ at the high rate). A no fertilizer treatment (check) was also included. Cogranulated urea-urea phosphate (UUP), urea-ammonium polyphosphate (UAP), UP, and UP combined with UAN were utilized in the broadcast experiment at two rates (34 and 68 kg N ha⁻¹). Triple superphosphate (0-20-0) was used to equalize applied P at 80 kg ha⁻¹ in the broadcast experiment. A treatment with 80 kg P ha⁻¹ applied (check) was also included. Evaluations of the treatments in each experiment were made utilizing plant population at emergence, nutrient concentrations in the plant at tillering and maturity, and final yields of aboveground dry matter and grain. These comparisons indicated all materials had little if any effect on plant population at emergence, were equally effective at supplying nutrients to the plant, and increased yields in both seed placement and broadcast experiments. Although acid-base materials were not shown to be superior to current materials, they may provide additional alternatives in soil fertility programs in similar environments.