Distribution of Phosphorus in Some Genetically Related Loess-Derived Soils1
- Curtis L. Godfrey and
- F. F. Riecken2
The total and organic phosphorus were determined in five virgin-like loess-derived soil profiles occurring along a traverse from southwestern Iowa to northern Missouri. The soils studied were representatives of the Prairie (Brunizem)3, Wiesenboden, and Planosol great soil groups. The time of soil weathering was assumed to have been the major soil formation variable affecting the soils investigated. The degree of soil profile development in southwestern Iowa had been found previously to increase maximally in a southeasternly direction from the major source of loessial material at the Missouri River.
The total phosphorus was found to decrease in the profiles along the traverse in relation to the degree of profile development, and the vertical distribution was found to vary in a systematic manner also. The action of soil weathering was found to have reduced the amount of phosphorus in the A horizons of the soils in relation to the amount found in the C horizons. The phosphorus measured on the B horizons was less than in the A or C horizons and decreased along the traverse to a minimum in the Haig profile (maximal Wiesenboden) and then increased slightly in the Planosol soils.
The organic phosphorus was found to decrease also in relation to the degree of soil profile development along the traverse and to decline vertically in the profiles at a progressively greater rate with each succeeding more strongly developed profile.
The data indicate a definite relationship between the amount and distribution of phosphorus and the stage of soil development exhibited in each of the profiles studied.
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