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Andrija Špoljar, Damir Barčić, Tomislava Peremin Volf, Stjepan Husnjak and Martinović Ivica

Abstract

The experiment was set up in the forest ecosystem with diverse vegetation zones in the area of Istria and the Croatian Littoral. Research included the following systematic soil units: lithic lepto-sols, rendzic leptosols, rendzic leptosols - eroded, mollic leptosols, chromic cambisol and chromic luvisols. The average quantity of the forest litter in the studied systematic soil units reaches 13.36 t/ha (Tables 1-3). The “wealth” of organic matter in the studied soil units can be presented with the following series: chromic cambisols (CMx) > mollic leptosols (LPm), organogenic, rendzic leptosols (LPk) > lithic leptosols (LPq) > chromic cambisols (CMx) - Terra rossa, chromic luvi-sols (LVx) > rendzic leptosols (LPk) - eroded. As expected, the lowest value of total nitrogen was found in the lithic leptosols in relation to almost all the other soils, except when compared with chromic cambisol and rendzic leptosols (p ⋋ 0.05). The statistically justified higher values of the percentage share of P2O5 in the forest litter were found in chromic luvisols and rendzic leptosols - eroded in relation to the other studied soils. Significantly higher level of copper contamination was inside rendzic leptosols - eroded in relation to the other studied soils. The exception is rendzic leptosols (p ⋋ 0.05). A significantly higher zinc content was detected in the lithic leptosols in relation to the other soil units, except for chromic luvisols, while a justifiably higher total lead and cadmium content in the forest litter was observed in chromic luvisols in relation to the other compared soils (p ⋋ 0.05).

Open access

Andrija Spoljar, Ivica Kisic, Tomislava Peremin Volf, Dragutin Kamenjak and Drazen Kaucic

Abstract

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).

Open access

Ivka Kvaternjak, Ivica Kisić, Marta Birkás, Andrija Špoljar and Dejan Marenčić

Abstract

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.