The Relationship Between Forms of Soil Phosphorus and Uptake of Phosphorus by Barley

The present investigation was suggested by the evidence that results obtained from some fertilizer experiments in the northern half of South Dakota related poorly to the soil test values. The yield increases from added phosphorus on fallowed land have not been as well correlated with soil tests as on non-fallowed land. A greater yield increase due to added phosphorus was obtained on fallowed soils having a high phosphorus test than on those having a medium test. Continued study was needed to determine the relationship between crop response to applied phosphorus uptake by plants, and the phosphorus fertility status of these soils as revealed by chemical methods. The availability of soil phosphorus to plants during the growing season may be a function of the solubility and amounts of all or certain forms of the phosphorus present in the soil. Variation in the tests between different groups of soils might also be due to the variation in the forms of phosphorus present in these soils. The objective of this investigation, therefore, was to study the relationship between crop response to applied phosphorus, phosphorus uptake by plants, and the phosphorus fertility status of these soils as revealed by chemical methods. The availability of soil phosphorus to plants during the growing season may be a function of the solubility and amounts of all or certain forms of the phosphorus present in the soil. Variation in the tests between different groups of soils might also be due to the variation in the forms of phosphorus present in these soils. The objective of this investigation, therefore, was to study the relationship between the various forms of soil phosphorus and plant-available phosphorus. Taken up by barley plants grown on these soils in the greenhouse. It was hoped that by separately determining the amounts of the different forms of soil phosphorus and relating each of them to plant phosphorus availability a more rational basis for future development or selection of a soil test might be provided