Vízügyi Közlemények, 1947 (29. évfolyam)

1-4. szám - VI. Szakirodalom

(33) mical and physical characteristics of the soil in the plant cultivation and the nutrious conditions and features of the soil. The soil features and the soil composition — at least as deep as the plant root will reach — and the depths of the subsoil water level are shown in the notes which are part of the attached explanatory pamphlets in detail while the numbers appearing in the map denote such features approximatively. The chemical characteristics (conditions of calcium content) as well as the physical characteritics (conditions of water-economy) are denoted in the maps by colours respectively by strips and points. These conditions are established through data derived by precise laboratory soil examinations, a summary of which appears also in the notes of the basic and detailed examination. The method of the soil examination and the cartographing make it possible at present to know precisely the soil features and characteristics almost all over the land. This soil survey embraces the entire territory of the country. The book informs us in five chapters of the natural features and of the factors and rules which assert themselves in the vegetation culture, i. e. it gives those directives for a rational plant culture which must be observed by using the data and maps at our disposal. Chapter I shows the climatic and meteorological features and their effect on the soil features and on the development of these. Chapter II treats the soil features and the characteristics which assert themselves in the plant cultivation. It explains the methods of the survey of the soil, the determination of the soil layers and the role of the subsoil water level in plant culture. It treats exhaustively the chemical peculiarity, the chemical effect, the measure of the saturation, the soluble salt content and the carbonic acid contents and their roles, furthermore, the peculiarities of the absorbing complex and the claims of the different plants in connection with these. With respect to the physicial peculiarities the capillary, absorbing and pervious capacities, the capability of swelling and of shrinking, the volume of voids, evaporating conditions, further the profitable water storing capability are treated with particular explanations, all of which play the most important roles in Hungarian plant culture. Chapter III informs us of the water economy on the soil and the plants. Dr. Kreybig takes pains in this chapter in explaining that the plant development is dependent on the possibility of precipation assertion in the soil peculiarities rather than on the amount of p ecipitation. There are soils which will return an excellent crop at a 300 mm precipitation while there are others which are unproductive even at a 600 mm rainfall even if such rainfall comes down to earth in favorable distribution. The profitable water storing capacity in the Hungarian soil at a depth of 150 cm varies in a favorable water content of the soil between 0 and 350 mm. The soils with a profitable storing capacity of 350 mm water are our most productive soils. The roles of the roots of the plants and of the methods in the cultivation are also treated in this chapter. Chapter IV treats the economy of nutritious food. On the basis of the latest biological findings it reviews the fertilizing factors and the feeding of the plants by the soil. Dr. Kreybig endeavors to prove by numerous soil research and precise outdoor experiments at large that the receptive capacities of the soil may undergo a great change in comparatively short time with respect of its nutritious substances both in a positive and negative direction. The researches and experimentations covering many decades have yielded the opportunity of establishing a new method which is based on the decaying process of the former crops, the stubble field, the remnants of the roots and the qualitative pecularities of the humus contained in the soil. So, for instance, it may be established that all soils in which the wheat crop is not satisfactory after the production of corn, beets or any other crop unfavorable to wheat, are positively craving for nitrogen even if the soil is rich in nitrogen substances. Unfavorable is the substituting of phosphoric and alkaline substances also in soils in which phosphoric or alkaline fertilizers are increasingly effective after fabacious plants. Dr. Kreybig established and has proven by experiments that for instance, phosphoric fertilizer in soils craving for nitrogen may in many cases unfavorably influence the crop and discusses this phenomenon. 3