Assessment of irrigation water quality at the territory of Vojvodina Province (Serbia)

Intensive crop cultivation systems require continuous monitoring of irrigation water quality as well as the control of physical and chemical soil properties. In view of the ongoing climate change and a dramatic decrease in soil organic matter content, the use of low quality irrigation water and its adverse effects on soil, cultivated plants and irrigation equipment must not be overlooked. The aim of this paper was to evaluate general quality of irrigation water from the different water intake sources in the Vojvodina Province. The paper presents the results of irrigation water quality, collected during 2018 and 2019. The research included 140 irrigation water samples obtained from three different intake structures which collect water from wells, canals or reservoirs. Water quality was assessed using the following parameters: pH value, electrical conductivity (EC), total dissolved solids (TDS), ionic balance, sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) value. Water quality diagram given by the US Salinity Laboratory (USSL) and FAO guidelines for interpretation water quality for irrigation was used. Additionally, the Nejgebauer classification for irrigation water, developed specifically for the area of Vojvodina, was used as a third classification. Based on the results of mineralization of the irrigation water, the following values of the observed parameters were determined: average pH of the analyzed water samples were 7.89, ranged from 7.14 to 9.01, while electrical conductivity values ranged from 0.10 to 3.50 dS/m, with an average of 0.85 dS/m. TDS analysis resulted in a wide range of values, from 112 mg/l to 2,384 mg/l, with an average of 529,22 mg/l. SAR values varied between 0.04-16.52 with a satisfactory average of 1.97. The USSL water classification produced similar results as FAO classification and RSC index <0, indicating that 57% of investigating samples are without concerns for irrigation use, whereas Nejgebauers classification and RSC index 0-1.25 show that over 75% of analyzed samples are suitable and safe for irrigation and soil properties. Since the quality of irrigation water significantly affects plant productivity, as it determines the chemical and physical properties of agricultural land, monitoring of water quality for irrigation is of high importance.