The So‐Called Solonetz Soils of California and Their Relation to Alkali Soils

During the past decade or two the Russian term "solonetz", and the contrasting term "solonchak", have come into rather general use among soil scientists the world over, as, of course, is well known to the members of this audience. However, these words are not always used in precisely the same sense. It seems appropriate, therefore, to introduce this discussion with a few remarks concerning the meaning of these words. It is obvious, it would seem, that there must be agreement as to the meaning of a given word; before it is possible to convey a definite idea by its use. The author has made some inquiry concerning the origin of the terms "solonetz" and "solonchak." The results have not been entirely satisfactory. It is clear, however, that the word solonetz is used by soil scientists, especially in Europe, in two senses; namely, morphologically and chemically. The root icl, common to both solonetz and solonchak, denotes salt. The ending, corresponding to the etz of solonetz, is probably an ancient form used to denote the diminutive. It would seem reasonable to conclude then, that the word solonetz, as applied to soil, literally denotes soil containing relatively little salt. This interpretation is harmonious with the generally accepted meaning of the contrasting term solonchak, which is used to mean soil containing relatively much salt. It is highly probable that the words solonetz and solonchak originated among the peasants of southeastern Russia centuries ago. Just when, and how the term solonetz came to have the morphological significance, now given to it by soil morphologists, is unknown to the writer. According to Vilensky (11), the presence of columnar horizons in alkali soils was first pointed out by P. A. Zemiatchensky in 1894. Briefly, we may say that various Russian soil morphologists have used the term solonetz to denote alkali soil the profile of which presents a certain type of morphology, and they use the term solonchak to mean saline soil without characteristic structure. On the other hand, Gedroiz and his followerers define solonetz as alkali soil containing only a small amount of soluble salts and significant amounts of absorbed or replaceable sodium; and they use the term solonchak to mean simply saline soil. Gedroiz repeatedly emphasized the point that solonetz is alkaline chemically, and although he commonly neglected to specify which soil horizon he was discussing, it is probable that he meant the columnar horizon. Gedroiz (1, 2, 4) developed an elaborate hypothesis by which he explained the properties, both chemical and physical, of solonetz. The gist of this hypothesis is that solonetz is derived tfrom sodium saline Boil through leaching. During the saline period the soil acquires absorbed sodium by base exchange. Later, when leaching conditions are established, the soluble salts become leached down into the lower horizons of the soil, whereupon the clay and humus of the soil, being more or less saturated with sodium, owing to base exchange during the saline period, become highly dispersed and alkaline due to hydrolysis of the sodium absorption complexes. The result of this dispersion is the gradual elutriation downward of clay and humus with the consequent development of dense subsoils. Gedroiz's publications show quite clearly that his interest was primarily centered on explaining the socalled solonetz properties of the soil, their origin and formation; whereas the soil morphologists of Russia have for several decades been concerned mainly with giving descriptions of the profile of such soil, with only a minimum of attempt to explain why or how their properties have arisen.