External factors and their impacts on soil features
1995
Bielek, P. (Soil Fertility Research Inst., Bratislava (Slovak Republic))
High levels of external impacts on soils is a typical phenomenon of developed and advanced agriculture. In Slovakia from 1945-1985 the total soil acreage was reduced by 307 thousand ha. Almost 450 thousand ha of agricultural soil (18 %) are drained, and more than 310 thousand ha (12 %) are irrigated. Mineral fertilizer consumption was increased from 14 N, 10 P2O5, 17 K2O kg per ha (1955) to 103 N, 83 P2O5, 80 K2O kg per ha and 31 N, 7 P2O5, 6 K2O kg/ha (1994), respectively. The soil changes arising from this are discussed. Figures illustrate soil nutrient stores, the effects of nitrogen fertilizer rates on yields of rape, sugar beet and maize, average contents of NO3 in ground waters of Slovakia, and intensities of soil mineral nitrogen accumulation in relation to yield potential. Tables show nitrogen, phosphate (P2O5) and potassium (K2O) balances from 1955-1994, and average nitrogen oxides released yearly from plant soil into the air in the Slovak Republic
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