Date of this Version
Thesis (M.S.)--University of Nebraska--Lincoln, 1959. Department of Agronomy.
The object of this study was to determine the relative availability of some of the phosphorus-bearing fertilizers sold in Nebraska. As one means of achieving this objective, a survey was made of the water-soluble phosphorus contained in mixed fertilizers sold on the Nebraska market. Water solubility was determined on several phosphatic fertilizer samples received by the State Department of Agriculture in its registration and inspection program.
A greenhouse experiment was conducted to evaluate the significance of water solubility in relation to residual fertilizer availability. Six dominant fertilizer mixes on the market, plus concentrated superphosphate and ammonium phosphate, were applied to four soils in a mixed and a banded placement. The soils ranged from very low to very high in phosphorus activity and from strongly acid to alkaline in soil reaction. Oats and subsequent crops of alfalfa were used as indicator crops.
A second experiment was conducted in the field to determine maximum application rates permissible with drill placement. The six mixed fertilizers, plus concentrated superphosphate, were drilled with winter wheat on the Agronomy Farm. Rates of 25, 50, 100 and 200 pounds per acre of available phosphorus were applied. Counts of the germination were determined and moisture samples of the soil were taken one and two weeks after planting.
Advisor: R. A. Olson.