Željka Zgorelec, Gordana Pehnec, Ferdo Bašić, Ivica Kisić, Milan Mesić, Silva Žužul, Aleksandra Jurišić, Ivana Šestak, Vladimira Vađić and Mirjana Čačković
Central gas station of the natural gas borehole system Podravina is located near the village Molve. It delivers more than a quarter of total energy used in Croatia to its consumers. Over the years, adapting technology to increasingly demanding and rigorous standards in environmental protection has become paramount. Yet, despite all the industry has undertaken to address the risk of harmful substances entering the food chain, a multidisciplinary research team of independent scientists monitors the content of specifi c substances in all components of the ecosystem. This paper presents measurements of total sulphur contents in soil surface [(0 to 3) cm] and subsurface [(3 to 8) cm] layers (study period: autumn 2006 - spring 2010) and in plants (study period: spring 2000 - spring 2010), and the concentration of gaseous sulphur compounds in the air. Concentrations of hydrogen sulphide (H2S) and mercaptans (RSH) were measured from the summer of 2002 until the autumn of 2010, while concentrations of sulphur dioxide (SO2) were measured from the spring of 2008 until the autumn of 2010. The paper also shows total annual atmospheric sulphur (S-SO4) deposition at Bilogora measuring station (study period: 2001 - 2010). Average monthly concentrations of H2S in air varied between 0.2 μg m-3 and 2.0 μg m-3, RSH between 0.1 μg m-3 and 24.5 μg m-3, and SO2 between 0.4 μg m-3 and 2.8 μg m-3 depending on the location and the season of sampling. Mean values of total sulphur in soil and in Plantago lanceolata plant ranged between 610 mg kg-1 and 1,599 mg kg-1 and between 3,614 mg kg-1 and 4,342 mg kg-1, respectively, depending on the soil type, location, and sampling depth. Average values of total sulphur mass ratio for all examined single soil samples (n=80) were 1,080 mg kg-1 for both studied layers, and 4,108 mg kg-1 for all analysed plant samples (n=85). Average total annual atmospheric sulphur deposition at Bilogora measuring station was 6.3 kg of S-SO4 per hectar.
Ivka Kvaternjak, Ivica Kisić, Marta Birkás, Andrija Špoljar and Dejan Marenčić
At the experiment station of the Krizevci College of Agriculture, yield and yield components of maize (Zea mays L.) and soybean (Glycine max) grown in rotation under five different methods of tillage were investigated. The aim of this study was to determine the effect of different tillage methods on yield and yield components of maize and soybean. The results and the determined number of plants per hectare of maize and soybean show that more favorable conditions for germination are in variants where ploughing performed in the autumn (variants C, D and E). During a four-year study, the minimum number of plants per hectare of maize and soybean was found in variant A. The dry season in panicle stage of maize in 2006 has lowered yields compared to 2008, and the drought in 2007 during the seed-filling period reduced the yield and the 1000 kernel weight of soybean compared with 2009 in all variants of tillage methods. The highest grain yield of maize was recorded in variant B. During 2006, with the unfavorable weather conditions, the lowest grain yield of maize was recorded in variant E with intensive tillage treatment. The highest yield of soybean was recorded in variant E, but there were no statistically significant differences compared to variants with the reduction of additional tillage interventions (variant B, C and D). With respect to maize grain and soybean seed yield, variant A was the lowest. Considering the achieved yields of maize grain, there is a possibility of reducing additional tillage interventions, whilst for achieving higher yield of soybean seed intensive tillage is recommended.
Spoljar A., Kisic I., Peremin Volf, T., Kamenjak D., Kaucic D.: Influence of climate change on soil water regime in Koprivnica-Krizevci County. Ekológia (Bratislava), Vol. 33, No. 2, p. 178-187, 2014.
The influence of climate change on soil water regime was investigated in the area of Koprivnica- -Krizevci County (Republic of Croatia). Water balance calculations were done for three climatic stations using Thornthwaite and Palmer water balance methods. In the 18-year period (from 1991 to 2008), compared with the previously observed 30-year period (from 1961 to 1990), the increase in average mean annual temperature was 1°C. Regarding the global warming, there was an increase in plant water potential during the investigated period. Compared with the previous period and according to Thornthwaite and Palmer methods, there was an increase in water deficit. Negative linear trend in precipitation was detected for all climate stations in the investigated area (p > 0.05) as well as positive linear trend in mean annual temperature (p < 0.05). The calculation of linear trend in water deficit in soil, according to Thornthwaite method, shows that by the year 2020 there could be an increase in water deficit by an average of 13 mm (p > 0.05), whereas according to the Palmer method there could be an increase by an average of 9 mm (p < 0.05 only for the climate station in Krizevci).