Nitrogen balance and mineral nitrogen content in the soil in a long experiment with maize under different systems of N fertilization
2003
Balik, J. | Cerny, J. | Tlustos, P. | Zitkova, M. (Ceska Zemedelska Univ., Prague (Czech Republic))
The effect of different systems of N fertilization on N balance and N transformation in the soil was studied in long-term stationary experiments (1991-2002) with successive growing of maize. Average dry matter yield was by 2-2.9 t less without fertilization vs. fertilization treatments. Significant differences between the control and fertilization treatments were determined for the first time in the 4th experimental year. Average N uptake by the aboveground biomass was 116 kg N/ha for the control, 162-170 kg N/ha for fertilization treatments. All experimental treatments had a negative balance of N inputs and outputs. The content of total C and N was lower in the topsoil treated with mineral fertilizers than in those treated with organic fertilizers and control topsoils. Concerning the content of mineral N and extractable N and C (extractions with 0.01M CaCl2), the control topsoil was the most stable followed by that treated with farmyard manure. Soil lysimeters installed in the depth of 60 cm (size 0.2 square m) showed that the amount of N-NO3-/ha in lysimetric waters after eight years (1994-2002) was 11.78 kg N-NO3-/ha in the control soil and 21.0-58.2 kg N-NO3-/ha in experimental soils. Nitrate concentrations in lysimetric waters were reduced by straw application.
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