Vodno fizička svojstva karbonatnog černozema u uslovima navodnjavanja povrća / Water physical properties of calcic chernozem in vegetable production under irrigation

Land and water are important natural resources, which are substantially altered by its use. Land is a nonrenewable resource, whose anthropogenization often leads to degradation. Improper or unconscious use of irrigation usually leads to detrimental effects on soil. In Vojvodina there are soil and climate prerequisites that can cause soil salinization in irrigation systems, especially irrigation water is saline. Correct (rational) irrigation means good understanding of soil and climatic conditions of the area and the biological characteristics of cultivated plants. Direct impact of water and irrigation on soil should be distinguished from the effects of agricultural technology and other factors and conditions. The aim of this study was to determine whether long-term irrigation, in intensive vegetable production, caused the change of morphological, hydro physical and chemical properties of carbonate chernozem. If rational irrigation is applied, in respect to hydropedological soil properties and biological characteristics of cultivated plants, the assumption is that the investigated chernozem soil will not show signs of degradation. Investigations were carried out at the Experimental Field of the Institute of Field and Vegetable Crops, Novi Sad, in the Department of Vegetable Crops. For the purpose of analysis eight soil profiles were dug up to two meters deep, four on land that is irrigated by sprinkling continuously since 1946 and four on land that has never been irrigated. Water for irrigation was from the wells. For the purposes of laboratory tests, disturbed and undisturbed soil samples were taken from the mid-determined genetic horizons, as well as irrigation water samples. Physical, water physical and chemical soil properties and chemical properties of irrigation water were analyzed by standard methods that are used for this type of research, as well as the modern world-recognized methods. Data were analyzed using analysis of variance and Duncan's LSD test for significance level of 5%. In order to objectively determine the impact of irrigation on water physical and chemical properties of soil, multivariate numerical (claster) method for the simultaneous analysis of large number of data was also used. The results showed that there was deterioration in water physical properties of chernozem, which, however is not the result of irrigation, but other anthropogenic and natural factors. It was also found slight deterioration of chemical properties of the soil as a result of the irrigation with saline water. It was found an increase in soil pH, higher content of calcium carbonate due irrigation and lower humus content due to increased microbial activity and faster mineralization of organic matter in favorable conditions of soil moisture. The increase of salt amount was also found. Although there was a slight increase in salinity, total amount of salt and ECe values are below the threshold for indicating the soil as saline. The results indicate a mild trend of deterioration of chemical properties of soil under irrigation. Therefore, periodic quality control is suggested, not only for irrigation water, but also for the soil. The results and conclusions are the basis for taking the necessary measures in order to preserve the soil quality.