Irrigation possibilities of the soils from the Northern agricultural region of the Republic of Moldova located in the river basin of the Prut

Currently, irrigation is considered one of the main factors for regulating and improving the soil moisture regime, but the establishment of soil irrigation systems for fruit trees in some agricultural areas of the Republic of Moldova is problematic and deficient.Researching soil cover within the river basins, evaluating the suitability of lands and soils for irrigation, highlighting the ecological problems that may occur, simultaneously with evaluating the quality of various water types suitable for irrigation represent current and important issues for all agricultural areas of the Republic of Moldova. The problem becomes even more pressing in connection with the adoption of the „Regulation on the use of groundwater for drip irrigation of agricultural land occupied by horticultural crops” (GD RM 635/2020 of 19.08.2020). Previously, the irrigated land in the Republic of Moldova included mostly typical and carbonate chernozems and some alluvial soils. The paper aims to avoid and minimize the impact of anthropogenic degradation of soils affected by intensive agriculture, under different crops, including fruit plantations and consequently not compromising long-term investments, such as establishing horticultural plantations, given that groundwater is unacceptable for irrigation, therefore the soils, depending on their suitability, can create ecological irrigation problems. Soil cover and water quality in various localities of the 2nd ecopedological district of the Republic of Moldova were investigated. The soil type of Moșeni village, administrative district Râșcani, consists of cambic chernozems in proportion of 75%. Here, over 100 ha of intensive orchards were established and the water suitable for irrigation is missing

INDEX OF UNDERGROUND WATER POLLUTION WITH NITRATES: SPRINGS AND PUMPS IN THE NISTRU BASIN

Assessing the springs and pumps water quality (in the Nistru basin) it was found that in most of the districts there are sources of unpolluted water (8-58%), poorly polluted (10-56%) and moderately polluted (4-42%) waters with nitrates. Springs with significantly polluted water were found in Causeni district (33%) and with very significant pollution were identified in Ialoveni districts (26%), Anenii Noi (20%), Criuleni (15%), Rezina (14%) and Soldanesti (12%) districts, demonstrating the impact of the landfills on the accumulation of nitrates in the groundwater.</p

DEPOSITION OF SULPHUR AND NITROGEN VIA RAINWATER (CASE STUDY - the administrative territory of the Hincesti district)

Deposition of Sulphur and Nitrogen from rainwater (case study – the administrative territory of the Hincesti district)*. The quantitative estimation of rainfall and determination of their chemical composition (samples collected in open area and under the canopy) lead to periodic assessment of the annual flow of ions and mineral deposits of sulfur and nitrogen oxide in the atmosphere. In accordance with agreed European Scale for assessing levels of atmospheric deposition it can be appreciated that the study area (Hincesti, central part of Moldova) in 2006-2010 corresponds to the class of large sulfur deposits, varying from 14.9 kg/ha/year (2009) to 24.8 kg/ha/year (2010). Quantities referring to study area recorded intermediate values – 16.8 kg/ha/year and 22.4 kg/ha/year respectively for the years 2007 and 2008.A comparison between annual average values of sulfur deposition recorded in open area at European level in the period 2006-2010 lies in the study area comparable to the central-eastern Europe region, exceeding 60% of the average. In relation to this scale deposition of total nitrogen (from nitrate ion and ammonium ion) are small-sized deposits in the area, with averages ranging from 2.2 to 4.3 kg/ha/year N-NO3- and 7.2-9.3 kg/ha/year for N-NH4+. There are slight oscillations of annual averages from year to year that do not exceed 0.6 kg/ha/year

THE WATER SPRINGS - SOURCES FOR WATER SUPPLY AND IRRIGATION IN THE NISTRU RIVER BASIN

The present study estimates chemical composition and status of the groundwater from the Dniester river basin. Research includes defining of springs/fountains location, evaluating physicochemical features of water, highlighting of main pollutants and pollution sources, establishing of water type and quality. The research was achieved within the State Program "Scientific research and water quality management"

ECOLOGICAL POTENTIAL OF SURFACE WATERS IN NATURAL SCIENTIFIC RESERVE “LOWER PRUT”

The research results have marked a low value of the self-purification capacity for Beleu Lake water, between 0.12 and 0.19, which is of 1.2-2 times smaller than the one from Prut River (0.25), correlating positively with the values of BOD5, COD-Cr and the time of biochemical oxidation of ammonium ions. The evolution of stage NH4+(NH3) → NO2- in the process of nitrification in lake water in November 2014 takes place about 25 days and the process NO2- → NO3- - more than 35 days, the duration about 2 times higher than in lake water stages from 2015 and 2.8-3.0 times higher than that of the model with water from Prut River