Calcium and magnesium requirements of soybeans as related to the degree of base saturation of the soil
1950
Welch, C.D. | Nelson, W.L.
The effects of rates and source of lime were studied for 3 years at each of three locations. Hydrated calcitic and dolomitic lime were applied to produce, theoretically, 30, 60, and 90% base saturations on the Craven and Bladen soil series and 20, 40, and 80% on the Hyde series. Calcium sulfate was added to supply calcium equivalent to the intermediate base saturation. The colloidal fraction of the Hyde is predominantly organic, the Craven largely kaolinitic, and the Bladen an organic-montmorillonitic mixture. These soils were located in the soybean producing area of eastern North Carolina. Ogden soybeans were grown on the same plots in 1945, 1946, and 1947. Calcitic lime increased yields at all locations. The first increment was generally sufficient. This resulted in calcium saturations of 19, 31, and 27% in the Hyde, Craven, and Bladen series, respectively. The responses to dolomitic lime were much the same as with calcitic. There was some indication, however, that a higher base saturation was required with the dolomitic limestone and this was closely related to the amount of calcium supplied. Applications of nitrogen increased yields on the most acid soil where no lime was applied and also in the calcium sulfate treatment (pH 4.2). Yield increases were obtained from manganese sulfate in the treatment receiving the high rate of calcitic lime. Both lime and nitrogen increased the nitrogen content of the leaves. There was no effect on the oil and nitrogen content of the seed, however.
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