Economic balance of nitrogen, phosphorus, potassium, magnesium, and selected calcium items in Czech agriculture since 1986
1997
Vostal, J. (Ceska Zemedelska Univ., Prague-Suchdol (Czech Republic))
The economic balances made for the period 1986-1995 quantify as assets the amount of nitrogen, phosphorus, potassium and magnesium applied in manure fertilizers, regarding nitrogen, they include also the amount of symbiotic fixation. There is included the amount of nutrients exported by harvest of plants. Compared to the period 1986-1990 there are important changes. There occurred a decrease of nutrients input by fertilizers, especially by mineral fertilizers. These changes have resulted into the passive economic balance after 1990, which is especially obvious regarding phosphorus, potassium and magnesium. In the average of the years 1991-1995, the input of nitrogen per hectare of agricultural land was by 10.2 kg of N lower than the output, regarding phosphorus it was 13.6 kg of P205, for potassium 51.2 kg of K2O and for magnesium 7.6 kg of MgO. The main source of these nutrients, except nitrogen, became manure. The consumption of lime decreased substantially. In consequence of the decreased nutrients input, the yields of most plants grown on arable land lowered after 1990 by 5.9-16.3 % (except flax and sugar beet) and those of grasses decreased by 21.9-27.7 %.
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