The present study is focused on the correlation between varied long-term fertilization and changes in soil nitrogen concentrations. it was found that all fertilization systems significantly increased the levels of total, mineral and organic nitrogen in the soil profile. organic fertilizers (manure and slurry) contributed to a more considerable increase in the concentrations of total nitrogen and nitrogen undergoing hydrolysis in 6M HCl, compared to mineral fertilizers. ammonia nitrogen dominated over nitrate nitrogen among mineral nitrogen forms. organic fertilization contributed to nitrate nitrogen accumulation, while mineral fertilization to ammonia nitrogen storage. The highest accumulations of nitrate nitrogen and ammonia nitrogen were observed after the application of slurry and manure, respectively. Hydrolyzable nitrogen content and its proportion in total nitrogen generally decreased with soil depth. an increase in the levels of organic nitrogen forms, i.e. nitrogen contained in amino sugars and amino acids as well as ammonia nitrogen from decomposition of amides, amino sugars and amino acids, was conditioned primarily on the application of organic fertilizers, particularly manure. amino acid-n dominated among hydrolyzable nitrogen compounds (77%), while amino sugar-n accounted for 5.6% only.
Abstract:The objective of the study was to compare the impact of three systems of multiannual fertilization applied in two long-term fi eld experiments on the content of phenolic compounds in the soil. In the study, both natural (manure, slurry) and mineral (NPK) fertilizers were used, along with combined, organic-and-mineral fertilization. Experiment I was established in 1972 on grey brown podzolic soil; experiment II, in 1973 on brown soil. In both experiments crops were cultivated in a 7-year rotation, with a 75% share of cereals. The experimental samples were taken from the top layer of soil after 36 (experiment I) and 35 (experiment II) years following the establishment of the experiments. It was demonstrated that the presence of phenolic compounds in the soils was signifi cantly dependent on the contents of organic C and total N, type of soil and the type and dose of used fertilizers. In grey brown podzolic soil, the content of total phenolic compounds was at a lower level than the content found in brown soil. Multiannual fertilization contributed to an increase in the content of total phenolic compounds in relation to the values obtained in control objects, which was particularly refl ected in the soil originating from objects fertilized with slurry applied at a dose being equivalent to manure in terms of the amount of introduced organic carbon. The percentage of water-soluble phenols in the total content of these compounds in grey brown podzolic soil was at the level of 18.4%, while in brown soil it amounted to 29.1%.
A field experiment was established in 1972 on Luvisol. Three types of fertilizers – cattle manure (CM), cattle slurry (CS) and mineral fertilizers were used. CS was applied in the following doses: I – balanced with CM in terms of the amount of introduced total nitrogen and II – balanced with CM in terms of the amount of introduced total organic carbon (C<sub>tot</sub>). 39 years after the experiment was established, half of each experimental plot was limed and since then the experiment was carried in two series – non-limed and limed soils. The paper presents the results of soil analyses 41 years after the experiment was started. It was found that each fertilization system increased the C<sub>tot</sub> content in soil in relation to the unfertilized control plot. The increase of C<sub>tot</sub> fluctuated between 0.35–6.22 g/kg of dry matter. In both series, the highest C<sub>tot</sub> content was observed in the soil fertilized with CM and CM + PK. Limed compared to non-limed soil contained nearly 25% more carbon of humic acids than fulvic acids and nearly 20% lower content of low molecular humic bonds. Liming considerably widened the humic acids carbon:fulvic acids carbon (C<sub>HA</sub>:C<sub>FA</sub>) ratio of the fertilized soils, up to 1.32–1.87, while the corresponding objects of the non-limed series showed the C<sub>HA</sub>:C<sub>FA</sub> ratio between 0.75–0.97.
Paper production is among the industrial branches generating significant amounts of waste. Organic waste from paper manufacturing is mostly used in gardening and agriculture or converted for energy purposes, while inorganic waste, including green liquor dregs (GLD), is usually deposited on landfills. GLD has a highly alkaline reaction, suggestive of its possible utilization for land reclamation or for improvement of soil's physico‐chemical properties. The research results originate from a pot experiment with maize as the test plant. GLD was added to soil in doses 10–40 t ha−1. The trials consisted of two series: with and without tree bark (TB). GLD contributed to neutralization of the soil's acidic pH, enrichment of the sorption complex with alkaline cations, and to greater salinity of the soil. In the series with TB, it is demonstrated that GLD led to a decrease in the soil content of total organic carbon; while the content of total nitrogen increased, the C:N ratio is considerably narrowed. In response to GLD, the greenness of leaves significantly improves, but this does not translate into an increase in the yield of plants. Regarding the chemical composition of plants grown in soil treated with elevated GLD doses, the content of N and Na is demonstrably higher, although no such effect is discernible in the case of P and K. For the environment, safe doses of the applied waste, not causing significant deterioration of soil properties or depressing crop yields, are 10 and 20 t GLD ha−1.
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