Nitrogen turnover of chernozem meadow soil in a long-term mineral fertilisation trial
2010
Izsáki, Z.
The elaboration and introduction of an environment-friendly N fertilisation system requires studies on the soil N regime, and on NO <sub>3</sub> -N accumulation and leaching under field conditions. The present work aimed to provide data on the soil N balance and on the depth distribution and leaching of NO <sub>3</sub> -N in chernozem meadow soil, based on the results of an 18-year long-term mineral fertilisation experiment. The soil contained 3.0–3.2% humus and had good N-supplying ability. Averaged over 18 years, the plant N uptake on plots without N fertilisation was 126 kg ha <sup>−1</sup> year <sup>−1</sup> . At the 80 kg ha <sup>−1</sup> N rate the soil N balance was negative, with a mean plant N uptake of 170 kg ha <sup>−1</sup> year <sup>−1</sup> and a low rate of NO <sub>3</sub> -N leaching was observed. At 160 kg ha <sup>−1</sup> N the accumulated N balance was only slightly negative. In 7 of the 18 years plant N uptake was below 160 kg ha <sup>−1</sup> . Under the given experimental conditions, considering the natural N-supplying capacity of the soil, the 160 kg ha <sup>−1</sup> N fertiliser rate proved to be excessive, surpassing the N requirements of the potential crop yield in most years and resulting in NO <sub>3</sub> -N leaching. The N regime data indicated that the 240 kg ha <sup>−1</sup> N rate represented over-fertilisation in the given location.
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