Principles governing the reclamation of alkali soils

Abstract

does not appear. First page follows. Our present understanding of alkali soils is based on two lines of investigation. Hilgard(14) was chiefly responsible for the first of these. He showed that the peculiar properties of alkali soils are caused by excessive concentrations of soluble salts; and that while high concentrations of soluble calcium, magnesium, and potassium salts are often found, sodium salts usually predominate. The other phase of the subject, developed during the past twenty years by a considerable number of investigators, is concerned with the principles of base exchange. It has been found that soluble sodium salts, upon accumulating in the soil, react by base exchange with certain constituents of the soil, thus altering the ratio of its replaceable bases. The importance of this discovery inheres in the fact that the replacement by sodium of the bases which normally occur in soils profoundly affects the chemical, physical, and crop-producing powers of the soil. Generally speaking calcium is the dominant replaceable base of normal soils. Alkali soils, on the other hand, often contain much replaceable sodium. This fact has a very important bearing on the reclamation of alkali soils.