Results of 75 years of continuous fertilization experiments in skierniewice as a contribution to modification of fertilization

Abstract

Long‐term static experiments have been carried out since 1923 at the Experimental Field in Skierniewice, belongs to Warsaw Agricultural University. The soil of the Experimental Field belongs to the type of lessive of the very good ryeland complex. The content of silt and clay (particles < 0,02 mm) in particular genetic horizons is as follow: 15–17 % in Ap (0–25 cm), 10–12 % in Eet (25–45 cm) and 25 % in Bt and C (below 45 cm). Organic C content in the arable layer varies within 0,6–0,9 %. The precipitation is relatively low (520 mm) and its distribution ist rather unfavourable for cereals. Mean annual temperature amounts to 7,9 °C and average growth period is 215 days (air temperature above 5 °C). Farmyard manure lead, as compared to mineral fertilization to an increase of humus content, and available K. Humification coeffizient of C‐FYM is 6–8 %. To maintain for many years the pH values of soil at the level of 5,5–6,5, application of 1,6 t CaO/ha every 4 years is satisfactory. Much higher yield of plants was obtained on the fields with crop rotation with FYM and legumes than on the fields without either FYM or legumes. Rye grown seventy years in monoculture gives only slightly lower (by 10–15 %) yields than that cultivated in arbitrary crop rotation. At the similar N, P, K rates brought into soil with farmyard manure and mineral fertilizers, higher yields of rye and potato in monoculture are obtained with mineral fertilizers. Content of total org. C and N during last 33 years is equal in treatments without either mineral or organic fertilizers, a little increased with the mineral fertilization and at highest in the FYM+mineral fertilizers treatments. Losses of nitrogen from top soil layer are higher from FYM than from mineral fertilizers.