Peter Kováčik

Carbon sequestration and its dynamics in water-stable aggregates

Abstract Sequestration of organic carbon in soils is an effective strategy to mitigate global climate change. Carbon sequestration leads to an increase in carbon stocks in soil, thereby reducing greenhouse gas emissions while improving soil quality and crop production. There are several published articles containing information in which the authors explain carbon sequestration in different soil types under different climatic conditions or farming systems, but on the other hand there is less information about carbon sequestration in water-stable aggregates. In field experiment, the manner in which different soil management practices influence carbon sequestration and its dynamics in water-stable aggregates was studied. We evaluated the soil samples taken from Haplic Luvisol (Dolná Malanta - Slovakia) from all treatments of tillage (conventional, minimal and grassland) and fertilisation (without fertilisation, crop residues together with NPK fertilisers and only NPK fertilisers). The maintenance of carbon concentration within soil under conventional tillage and in native grassland was due to an enhanced incorporation of new organic matter from the coarse fraction of particulate organic matter to macro-aggregates and in treatment with ploughed crop residue together with NPK fertilisers, there was besides of this caused by the reduction of carbon mineralisation from the fine fraction. Soil management practices have a significant effect on the re-distribution of soil organic matter in water-stable aggregates. In conventional and minimal tillage, very important sources of carbon sequestration are agronomical favourable size fractions of water-stable macro-aggregates and in native grassland, as well as in all fertiliser treatments, the most important source of carbon sequestration is water-stable micro-aggregates.

THE IMPACT OF FRESH SAWDUST AND DRY PIG MANURE PRODUCED ON SAWDUST BEDDING APPLICATION ON THE NUTRIENTS MOBILITY IN SOIL AND SUGAR BEET YIELD

The objective of the pot trial carried out at the area of the Slovak University of Agriculture in Nitra was to determine the impact of dry pig manure produced on the sawdust bedding and sawdust litter on the level of nutrients’ mobility in the soil and sugar beet yield. The achieved results showed that one month after the sawdust and manure application to the soil, the contents of mobile nutrients (N an , P, K, Ca, Mg) in soil were lower than in the control unfertilized treatment. The sawdust litter immobilized nutrients more considerably than manure. Four months after the manure application into soil, its immobilization effect was not evident. On the contrary, the manure increased the mobile nutrients content in soil. In the second year of experiment the immobilization effect of sawdust litter was proved even four months after its application into soil. The application of manure increased considerably the beet root yield. The maximum root yield was determined in the treatment where the highest dose of manure was applied. The minimum root yield was detected in the treatment where the highest dose of sawdust litter was applied.

THE EFFECT OF DIFFERENT DOSES OF N FERTILIZATION ON THE PARAMETERS OF SOIL ORGANIC MATTER AND SOIL SORPTION COMPLEX

Mineral N fertilizer application may have an effect on soil organic matter and other soil parameters. Therefore, we studied the effects of different doses of N fertilization on soil organic matter and chemical properties of Haplic Luvisol in the locality of Dolná Malanta (Slovakia) during 2014–2016. Soil samples were collected from the plots exposed to the following treatments: 1. N0 – no N fertilization as control during 2014–2016, 2. N40 – N fertilizer at the rate of 40 kg N ha–1 in 2014 and 2016, 3. N80 – N fertilizer at the rate of 80 kg N ha–1 in 2014 and 2016, 4. N160 – N fertilizer at the rate of 160 kg N ha–1 in 2015, and 5. N240 – N fertilizer at the rate of 240 kg N ha–1 in 2015. The results showed that in N80 the soil organic carbon (SOC) content increased by 32% in comparison to N0. The addition of 80 kg ha-1 of N significantly decreased the humic substances (HS) content in the soil by 16% compared to N0. The higher doses of N fertilization 80 rather than 40 kg ha-1 as well as 240 rather than 160 kg ha-1 significantly decreased humus stability. The addition of N fertilization decreased the average values of soil pH. Values of hydrolytic acidity (Ha) increased by 41% and 46% in N40 and N80, respectively than N0, but on the other hand, this one decreased by 36% and 27% in N160 and N240, respectively in comparison to N0. Positive statistically significant correlations were determined between soil pH and SOC in N40 and N80 treatments. The increase of soil pH was connected with higher humus quality in N160 and N240. Negative correlations between humic acids (HA) and sum of basic cations (SBC) and cation exchange capacity (CEC) were observed in N80 < N160 < N240 treatments. Higher values of fulvic acids corresponded with lesser CEC in N80 and N160 treatments. In N160, with increased humus quality, CEC significantly decreased. The same effect was observed in N240. In addition, in N240, we also observed that with increased HA:FA ratio SBC and base saturation significantly decreased.

Spring Barley Yield Parameters after Lignite, Sodium Humate and Nitrogen Utilization

Abstract The existence of a small number of publications dealing with the impact of solid sodium humate and lignite on the quantity and quality of grown crops was the reason for establishing the field experiment. The objective of this experiment was to detect the impact of solid lignite and solid sodium humate on the quantity and quality of spring barley yield. These substances were applied into the soil either independently or along with nitrogen fertiliser. The next objective was to determine the impact of foliar application of sodium humate water solution applied either independently or along with nitrogen fertiliser on the quality and quantity of spring barley yield. The achieved results showed that the autumn application of solid lignite and the presowing application of solid sodium humate into the soil tended to decrease the yield of both grain and straw of spring barley, crude protein content in grain, proportion of the first-class grains and volume weight of grain, whereas the impact of humate was more negative. Lignite and sodium humate in the solid form should be used along with nitrogen fertiliser. The application of sodium humate in liquid form during the growth season of barley tended to increase the yield of both grain and straw. The joint application of nitrogen and liquid sodium humate during the growth season of barley increased the grain yield of barley significantly. A lower dose of nitrogen, applied during the growth season of barley (growth season BBCH 23), increased the grain yield of barley considerably more than a higher N dose, applied into the soil before barley sowing.

IMPACT OF VERMICOMPOST EXTRACT APPLICATION INTO SOIL AND ON PLANT LEAVES ON MAIZE PHYTOMASS FORMATION

Nowadays in scientific literature many opposing data are presented of the impacts of vermicompost extract on the quantity and quality of crop production. Therefore, the principal objective of two independent experiments was to study the effects of vermiextracts, which were applied before maize sowing into soil and during the growing season on the maize leaves, on its phytomass formation. The first, field experiment consisted of 9 variants. Variant 1 was the control one without the extract application. We studied the effect of the rising doses (90, 130, 170, 210 dm3·ha-1) of vermi-extract applied into soil before the maize sowing in the variants E1, E2, E3, E4. In the variants E1+E, E2+E, E3+E, E4+E along with the rising doses of vermi-extract was also applied the uniform dose of vermi-extract (40 dm3·ha-1) at the growth stage BBCH 15. The second, pot experiment was pursued in the vegetation cage and comprised 3 variants: variant 1 was the control, in the variants 2 and 3 the foliar application of vermi-extract was used. The vermi-extract was applied once (growth stage BBCH 12) in the variant 2 and in the variant 3 it was used twice (at growth stages BBCH 12 and BBCH 16). The achieved results show that the vermi-extract applied in the presowing period increased the yield of maize grains if the application doses were 130–170 dm3·ha-1. The positive or negative impact of the foliar application by vermi-extract on the yield of maize grains depended on the period of application and the grown cultivar. In order to increase the starch content in grains it was more suitable to carry out the presowing vermi-extract application than during the growing season. The presowing application and the foliar application of vermi-extract tended to decrease the nitrogen content in grain. The foliar application of vermi-extract had the positive impact on the plant height and stalk thickness of the maize plants only in short term. The information obtained from the first half of maize growing season related to the plant height and stalk thickness was not the appropriate indicator for the assessment of maize grain yields.

GROWTH AND YIELD STIMULATION OF WINTER OILSEED RAPE (BRASSSICA NAPUS L.) BY MG-TITANIT FERTILISER

Abstract The effort to achieve higher yields at the required qualitative level has led to the intensive studying the problems of the rational usage of the titanium containing fertilisers by the agricultural research in the course the previous thirty years. Therefore, the objective of the experiment was to evaluate the impact of two doses of Mg-Titanit (0.2 l/ha and 0.4 l/ha) on the formation of the aboveground and underground phytomass, also on the total chlorophyll in leaves, on the titanium and nitrogen content in the seeds and straw, on the quantity and quality of winter rape yield. The doses were applied two or three times on the leaves of winter rape (BBCH 50-52, BBCH 59, BBCH 66-67). The experiment was realized on the Haplic Chernozem (48°42´ N, 17°70´ E - Western Slovakia) during two farming years (2009/2010 and 2010/2011). The results showed that all three applications of Mg-Titanit in both doses stimulated the formation of aboveground and underground phytomass of winter rape. The highest growth of phytomass was detected after the second application. The application of Mg-Titanit in the growth phases BBCH 50-52 and BBCH 59 increased the contents of both chlorophylls (a and b), where the growth of chlorophyll b content was more considerable than the growth of chlorophyll a content. The third spraying by Mg-Titanit decreased the content of the total chlorophyll. The application of Mg-Titanit had the positive impact on the yield of seeds, straw and fat content in the winter oilseed rape seeds.

Effect of a polyamine biosynthesis inhibitor on the quality of grape and red wine

BACKGROUND The quality of berries and red wines is influenced by the cultivar. The aim of this study was to determine the effect of a polyamine biosynthesis (PA) inhibitor on some red grapevine cultivars with a genetically lower quality of grapes and wines. O-Phosphoethanolamine was used as a PA inhibitor because of its positive effect on the quality of some small berries. RESULTS The PA inhibitor at a foliar dose treatment of 7.0 g ha(-1) significantly increased the peroxidation inhibition of berries (1.16- to 1.56-fold), the color density (from 1.66% to 69.14%) and the sensory quality of the wines with a lower genetically programmed color quality (André, Saint Laurent and Zweigeltrebe), but not the higher-quality Alibernet variety. The PA inhibitor predominantly decreased the total phenolic and anthocyanin contents (from 37.0% to 27.5%), and it significantly decreased the contents of free polyamines in all varieties-very dramatically in Saint Laurent grapes (17.16- to 1.58-fold). CONCLUSIONS Foliar treatment of red grapevine varieties of a low quality, using O-phosphoethanolamine, can help produce higher-quality wines.