Conversion of soil potash from the nonreplaceable to the replaceable form

Abel, F.A.E.; Magistad, O.C.

Conversion of soil potash from the nonreplaceable to the replaceable form

1935

Abel, F.A.E. | Magistad, O.C.

Two experiments were conducted in the greenhouse using eight pineapple soils all derived from basaltic lavas. In the first experiment successive crops of soybeans were grown on two soils, one well supplied and one deficient in replaceable potassium, each with and without lime. The soils in this experiment received no potassium as fertilizer but did receive nitrogen and phosphorus. A balance sheet of readily available potash was kept. In a second experiment similar to the first, six diverse soils were used, and two pots of each soil, limed and unlimed, were cropped with sorghum. One set of each soil remained fallow. The conclusions were that about 100 pounds of K2O per acre foot was made available from non-replaceable sources annually in the case of limed soils and about 75 pounds in the case of natural acid soils. The results were of the same order in the case of fallow soils, and with soils cropped with legumes on the one hand and nonlegumes on the other. Soils having a very low amount of replaceable potash at the beginning of the test were able to release potash from non-replaceable sources as readily as soils rich in replaceable potash.

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