Balance of potassium in two long-term field experiments with different fertilization treatments
2019
Balík, Jiří | Černý, Jindřich | Kulhánek, Martin | Sedlář, Ondřej | Suran, Pavel
Balance of potassium (K) was observed in long-term stationary field experiments (21 years) at two sites with different soil and climatic conditions (Luvisol, Cambisol). The following crops were rotated within the trial: potatoes- winter wheat-spring barley. All three crops were grown each year. The trial comprised 6 treatments: (1) no fertilization; (2) farmyard manure; (3) half dose of farmyard manure + nitrogen (N) in mineral nitrogen fertilizers; (4) mineral nitrogen fertilizers; (5) NPK in mineral fertilizers; (6) straw of spring barley + N in mineral nitrogen fertilizers. The recovery rate of potassium from farmyard manure by crops was 24–26%, from mineral fertilizers it was 27–52%. Different fertilization intensities were manifested by significant differences in the content of exchangeable K in soil. Changes in non-exchangeable K (K<sub>ne</sub>) were recorded only at the Luvisol site (850 mg K<sub>ne</sub>/kg), but not at the Cambisol site (3000 mg K<sub>ne</sub>/kg). The maximum negative balance (–2376 kg K/ha/21 years) was recorded at the mineral nitrogen fertilization treatment.
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