Effect of soil characteristics and fertilization on potatoes as regards yield and tissue composition

The application of 125 pounds of superphosphate (43% P205) per acre on 12 potato fields in the Red River Valley early in 1941 did not materially affect tuber yield. The application of 200 pounds of muriate of potash in addition to the phosphate produced increases of economic value. Rates of fertilization used did not induce marked changes in the concentrations of five elements (P, K, Ca, Mg, and Cl) in the four portions of the potato plant studied. The application of muriate of potash to the soil greatly increased chlorine concentrations in the tissues. Soil type influenced tuber yields with larger crops being produced on the finer textured soils. Higher fertility combined with greater water-holding capacity of the finer textured soils is probably responsible for the larger yields. Larger tuber yields were associated with increased concentrations of potassium in the plant tissues with an accompanying depression of calcium and of magnesium concentrations. Soils of varying carbonate content differed in their response to applied commercial fertilizer, with larger yield increases being observed in the fertilized low-carbonate soil group. Fixation of fertilizer may be more pronounced in the high-carbonate soils. Soil carbonate concentrations had little effect on potassium concentrations in the plant tissues, but depressed the phosphorus and increased the absorption of calcium and magnesium. Soluble sulfates present in the soil had no marked effect on tuber yield, response to fertilizer, or on tissue concentrations of K, P, Ca, and Mg. Larger amounts of sulfates were present in the tissues of the plants grown on sulfate soils, this factor tending to depress the excess absorption of chlorine. The grouping of the potato fields in four levels of apparent fertility showed increasing concentrations of potassium present in the tissues of the higher yielding plants. The concentrations of five other elements in the plant tissues studied showed no such consistent trends.