Vízügyi Közlemények, 1948 (30. évfolyam)

2. szám - VII. Szakirodalom

(58) DATA TO THE REGULATION OF WATER CONDITIONS IN HUNGARY IN VIEW OF CROP PRODUCTION. By L. KREYBIG, D. Eng. (See the map on page 205 in the Hungarian original.) D. C. 631.4 : 626.8 (439.1) The regulation of water conditions adapted to the requirements of soils and cultivated plants all over the country is a problem of vital importance to the security of a successful agricultural production in Hungary. •The predominating droughty periods of our specifically dry climate make it necessary that the soils should absorb and reserve, during the period from autumn to spring, the water needed by the vegetation as an addition to the usual small amount of precipitation to be expected in the following growing season. The smaller the quantity of humidity retained in the soil during the winter season, the greater are the drought damages throughout the growing season; on the other hand the greater the losses caused by run-off water from soils lying at somewhat higher elevations, the more water damages occur in soil expressions where the run-off water accumulates. The annual average precipitation in Hungary amounts to 500—600 mm plentifully sufficient for high crop yielding results, providing that this amount of rainfall is favourably distributed and the water management of soils is satisfactory. But the seemingly abundant precipitation shows divergent effects dependent upon its distribution in time and area, physical character and water management of soils, humidity requisite of cultivated plants, furthermore, methods applied to crop production, such as soil cultivation, manuring etc. This circumstance is considered to be the fundamental cause of drought damages in our country, and chiefly responsible for the differences in crop yields. This may also explain the fact that in various regions as well as within a relatively small area one plot is damaged by drought and the adjoining one by excess water. It is apparent that drought is not a menace of general features, as we have soils in the country which under equal conditions never suffer from so called catastrophic dryness while on others drought occurs year by year. We have to point out that in great many cases drought damages are not exclusively due to our unfavourable soil and climatic conditions but moreover to the culture-technical methods applied inadequately in crop production. These facts undubitably prove that the prevention and control of drought and water damages is in first rate a problem of civil-engineering that might be solved successfully by carrying out soil improving procedures, cultivation and manuring in perfect scheme to actual crop production accordingly. Spectacular results, however, may be reckoned on if civil-engineering operations are performed in accordance with soil and climatic conditions suited to crop production, and the farmer himself accomplishes reasonable soil management. A prime reejuisite of successful water regulation is a proper control of damages causeel bv excess water, anel furthermore, the lessening of drought damages. Drought damages occur under our specific climatic conditions when the soil has not the ability to retain sufficient rainfall amount during the period from autumn to spring, when the evaporation and run-off losses are to a great extent, anel finally, when the precipitation is not satisfactory throughout the growing season. The unfavourable characteristics of soil, its water management respectively, may be more or less improved, or at least counterbalanced with certain chemical soil meliorating procedures, specific tillage methods, adequate manuring and proper soil management, that means a reasonable selection of crops on their water requirements accordingly. There is a possibility to reduce the rate of losses caused by run-off waters applying farm terracing and special culturetechnical methods. Excess water damages are chiefly clue to the inundating water of flood area, the accumulation of topsoil water, and further, to the outburst of subsoil water. Nowadays inundation occurs in exceptional cases as our important rivers have undergone proper