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In this work are presented the results of investigations related to total and sulphate sulphur contents in humus horizon of arable soils of 15 Poznań province and their soil reaction. On the basis of obtained results it was found that analysed soils of municipalities contained from 9.0 to 182.0 mg total S/100 g of soil. The data follows that the content of total sulphur was differentiated not only between soils of researched municipalities but also in limit of each other. The quantitative differences of sulphate sulphur, which one content range from 0.03 to 19.7 mg S-SO₄/100g of soil corresponded with the differentiation of total sulphur. Soil reaction of the researched soils like sulphur was differentiated and ranged from pH 3.8 to 7.9.
Biological processes which shape soil fertility are affected by microorganisms and enzymes they produce as well as the rate of biogeochemical transformations in the cycling ofelements. One of the enzymes is arylsulphatase (EC 3.1.6.1.), which hydrolyses sulphate esters with aromatic radical, releasing sulphate ions according to the equation: R-C-O-SO3- + H2O  R-C-OH + SO42- + H+. The enzyme plays an essential role in the sulphur cycle in soil and it can be an indicator of sulphur mineralization in soil. For his study, soil was sampled from a field under potato fertilized with different doses of farmyard manure (0, 20, 40, 60 and 80 t·ha-1) and mineral nitrogen (0, 45, 90, 135 kg N·ha-1). The activity of arylsulphatase was assayed according to Tabatabai and Bremner, while sulphate (VI) sulphur was determined as described by Bardsley and Lancaster. The content of organic carbon in the soil ranged from 8.168 to 10.96 g·kg-1 and depended on FYM fertilization, while the content of total nitrogen ranged from 0.889 to 1.012 g·kg-1 with an average of 0.960 g·kg-1 for FYM and mineral nitrogen doses. The effect of fertilisation on changes in the amount of sulphate sulphur and the activity of arylsulphatase in the soil was noted. The content of sulphate sulphur throughout the research ranged from 21.49 to 24.83 g·kg-1. The higher the FYM doses, the higher the content of the fraction of sulphur available to plants. The soil provided a good supply of sulphur to plants. The activity of the enzyme ranged from 0.010 to 0.024 µM pNP g-1 ·h-1. Its highest activity (an average 0.018 pM pNP g-1·h-1) was recorded in the samples fertilised with nitrogen at the amount of 45 kg·ha-1. Both parameters changed during the potato vegetation period.
A three-year field experiment was conducted in Byszwałd near Lubawa in 2000-2002. The aim of this study has been to determine the influence of increasing rates of sulphur on the dynamics of available phosphorus in soil at two horizons: 0-40 and 40-80 cm. The trial was set up on acid brown soil of the granulometric composition of heavy loamy sand. The initial soil had the following properties: pH(KCl) = 5.30, mineral nitrogen 24.0, sulphate sulphur 4.10, available phosphorus 34.5 and potassium 110.0 mg kg-1 of soil. Three levels of sulphur fertilization were applied: 40, 80 and 120 kg⋅ha-1 in the sulphate form (S-SO4) and as elementary sulphur (S-S0). During the whole duration of the field trials, the results demonstrating the effect of fertilization with different forms and rates of sulphur on the content and transfer of available phosphorus in soil were inconsistent. Only the dose of 120 kg⋅ha-1 S-SO4 caused a significant increase in the concentration of available sulphur in soil in the 0-40 and 40-80 cm layers. All the rates of elementary sulphur as well as 40 and 80 kg⋅ha-1 sulphate sulphur caused little less but an increasing tendency in the content of phosphorus in soil. The effect of elementary sulphur became apparent as late as the third year of the trials. The effect of the doses of 40 and 80 kg⋅ha-1 of sulphur on properties of soil depended on the form of sulphur, duration of the experiment.
The assessment of fertilization impact on selected soil properties was made in a pot experiment in 2003-2005. The research was conducted on loamy sand, sandy silt loam and medium silt loam. Two sewage sludges from municipal mechanical-biological sewage treatment plants and compost produced of plant wastes were used for the experiment. Mineral fertilization caused the greatest changes of soil reaction. Smaller doses of organic materials reduced soil acidification. The value of electroconductivity raised most in effect of applied fertilization (after the first year of investigations) in the soil with the lightest texture. Greater diversification in the soils from organic treatments resulted rather from the applied dose than from the kind of fertilizer. Fertilization did not cause any major changes in the soil soprtion capacity. Organic carbon content in soils did not change significantly following the application of sewage sludges and compost in comparison with farmyard manure treatment. The content of zinc and manganese mobile forms increased in all treatments after three years. No similar changes were found for cadmium; its contents were similar after the first and third year. A considerable sulphur load supplied to the soils through organic treatment, particularly with sewage sludges and farmyard manure was reflected in the increased content of sulphate sulphur in the soils. After three-year period of investigations the tendency for the highest concentrations of sulphate sulphur in soils (particularly in light and heavy ones) fertilized with sewage sludges was maintained. The increase in this component content in soil after farmyard manure fertilization proved short lived.
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