Rola wybranych czynników agrotechnicznych w kształtowaniu substancji organicznej w glebie pod sadem

The studies were conducted in 28 years' old apple orchard in Łyczyn, situated on the lessives soil developed from light boulder clay. The influence of liming and nitrogen fertilization on applied the strips of fallow and grass, pH of the soil, content of organic carbon, carbon of humic acids and fulvic acids and carbon of humins was examined. Three levels of nitrogen fertilization were used: 40,140 and 240 kg N/ha, while the nonfertilized fields was the control. The soil samples for the studies were taken with use of Egner rod of 0-20 cm layer. The effect of the studied agrotechnical factors was different in the strips of grass and fallow land. Nitrogen fertilization and liming of the fallow land had influenced the content of carbon and also carbon of humins. In the case of the grassland, nitrogen fertilization and liming was favourable for accumulation of humic acids. The increasing doses of nitrogen fertilization caused the drop in pH of the soil, being especially high on the non-limed fallow land. The content of carbon of fulvic acids was affected mainly by the method of cultivation and nitrogen fertilization. In the soil under the fallow land, the content of carbon of fulvic acids was, in average, higher by 22.5%, as compared to that one under the grass.