REGIONAL CLIMATE CHANGES IN NORTH-EASTERN POLAND AND THEIR IMPACT ON MAIZE CROPS

Aim of the study. Indication of changes in maize yield for grain and silage in connection with the observed climate changes. Material and methods.Data from field experiments of the experimental station of the University of Warmia and Mazury since 1972 as well as meteorological data (air temperatures and precipitation). Calculations using the trend analysis of original variables and determined indexes (GDD, SPI, Sielianinov index), weather-yield linear models and elements of spectral analysis. Results and conclusions. Changes in thermal conditions were demonstrated based on average air temperatures and the GDD index. There were no significant changes in atmospheric precipitation, showing a small periodicity of ten years, and no changes in monthly frequency with a deficit of precipitation (SPI analysis). It was demonstrated that changes in thermal conditions as well as the introduction of new maize varieties over fifty years significantly improved plant maturation, which resulted in a significant increase in grain weight. However, this did not affect the yield of maize for silage, neither in crop rotation nor in the monoculture system.

ASSESSING WATER QUALITY OF BOYALI DAM LAKE (SINOP, TURKEY) BY USING ECOLOGICAL AND STATISTICAL INDICATORS

Aim of the study: In the present study, the spatial – temporal variations of water quality in Boyalı Pond were analyzed. Water Quality Index (WQI) based on the World Health Organization's standards specified for drinking water, and Water Quality Control Regulations in Turkey (WQCR), as well as certain multi-statistical methods, were used in analyzing the water quality. Material and methods: Water samples were collected from 5 stations selected in the lake on monthly basis in 2019 and 30 water quality parameters were measured in total. Water Quality Index (WQI), Factor Analysis (FA), and Cluster Analysis (CA) were used in order to determine the differences between the spatial and temporal quality levels and to classify the investigated locations. Results and conclusions: According to data observed, Boyalı Dam Lake was found to have Class I and Class II water quality in general the WQI results obtained suggested that, although the water quality was found to significantly decrease in summer months, the reservoir was found to have an "A Grade – Excellent" water quality (<50) in all the months and stations analyzed here. WQI values recorded in the dam lake ranged between 16.4 and 27.8 and the detected limnologic parameters did not exceed the standards specified for drinking water in any of the investigated months and stations (<50 for WQI). As a result of FA, 3 factors explained 88.9% of total variances and as a result of CA, 2 statistical clusters were formed.

ASSESSMENT OF CHANGES IN THE QUALITY OF GROUNDWATERIN THE REGION OF THE MUNICIPAL LANDFILL IN WOJKOWICE

Aim of the study. Landfilling is an activity, which may threaten the destruction or contamination of the soil and water environment. Pollution can be generated both by leachate and by landfill gas. Legal conditions impose on landfill managers to monitor groundwater around the landfills. The impacted soils and groundwater show high chlorides, sulphates, heavy metal concentrations especially as compared to natural hydrochemical background values. Monitoring results can be analyzed using pollution indicators. The objective of this study was to determine the quality of groundwater in a landfill in Wojkowice (southern Poland) using the Backman index. Material and methods. The novelty of the paper results from the use of a different range of parameters than initially included in the formula. The results of water quality monitoring for three piezometers from 2013–2020 were considered. The contamination index was calculated separately for each of the analysed water samples, taking into account the electrolytic conductivity and the concentration of total organic carbon (TOC), Cd, Pb, Zn, Cu, Cr and the sum of N-NO3, N-NO2 and N-NH4. Results and conclusions. The Backman index values range in the groundwater samples were –5.3 to 603. The value of the Backman index increases with the increase in the concentration of individual parameters in groundwater. In the case of heavily transformed areas, the water pollution index has high values, exceeding 3. The results of this index indicated that the quality of the groundwater around the landfill is bad. In the future, it is planned to expand the range of parameters for calculating the index.

ATMOSPHERIC DROUGHT IN THE POLISH TATRAS AND THEIRFORELAND IN THE YEARS 1951–2017

Aim of the study. The aim of this study is to assess the variability of the lowest monthly totals of precipitation, and to evaluate the impact of atmospheric circulation on the occurrence of months with a deficit of precipitation. Material and methods. Material: The monthly totals of atmospheric precipitation for the years 1951–2017 from 19 meteorological stations located in the Polish Tatra Mountains and in their foreland. and the calendar of atmospheric circulation types for southern Poland, which was developed by Niedźwiedź (1981; 2018). Methods: Standardized Precipitation Index (SPI), the Mann-Kendall test Results and conclusions. No statistically significant trend at a significance level of 0.05 was noted in the course of the lowest monthly precipitation totals at any of the meteorological stations. In the 67-year period, all the measuring stations saw a total of 499 (3.3%) dry months with varying drought severity. The largest number of extremely dry months occurred in August and April, respectively. In the case of months when the lowest totals of precipitation occurred in the same month at all or almost all of the meteorological stations, three types of anticyclonic circulation dominated, i.e. eastern, south-eastern, southern, and the anticyclonic wedge.

PHYTOTOXIC ACTIVITY OF BIOACTIVE COMPOUNDS FROM FOUR PLANTS AGAINST SELECTED WEEDS IN AGRICULTURE

Aim of the Study. Heavy doses of synthetic weed control chemicals have caused herbicide resistance in weeds. Natural com pounds produced by living organisms constitute a wide field for ecologically safe herbicides. The experiments were designed to test allelopathic potential of hexane extracts of selected plants against common weeds in agriculture viz. Euphorbia helioscopia, Rumex dentatus, Phalaris minor, Avena fatua and Chenopodium album. Materials and methods. Allelopathic potential of Carica papaya, Rhazya stricta, Lantana camara and Pinus roxburghii hexane extracts against weeds was determined at 100%, 75% and 50% concentration on soil, filter paper and agar. Parameters adopted for assessing allelopathic potential were the germination (%) and the length of seedling (cm). Data analysis was performed using the Statistica 9 software. Results and Conclusion. The results indicated that R. stricta, C. papaya, L. camara and P. roxburghii hexane extracts possesses suppression effects against weeds among which L. camara had the most conspicuous inhibition effects on selected weeds. The inhibitory effects of germination and seedling growth were in order R. stricta > L. camara > C. papaya > P. roxburghii. Field analysis to assess the phytotoxic ability of these species to be used as herbicide is recommended.