Effects of short-term fertilizing cessation on permanent grassland
1999
Jancovic, J. | Holubek, R. (Slovenska Polnohospodarska Univ., Nitra (Slovak Republic))
After 1-year stoppage in fertilizing a long-term fertilized grassland (1986-1993), the dominancy of flora groups was found to have changed in the variants fertilized by the use of increasing nitrogen doses and a periodical alternation of rates of nitrogen as well. Legumes were regenerated and the percentage of other herbs increased, too. After 8 years of previous fertilization, minimum changes in the stand composition were only observed in the grassland where a rate of 240 kg N/ha was applied. After fertilization was stopped, dry matter production decreased by 14 to 31% in the variants with increased rates of nitrogen, while in those using an alternative nitrogen application it increased by 19 to 30%, as compared to the inital year of a trial. As for the chemical composition, the grasslands with increased nitrogen application showed a significant reduction in the nitrogen concentration (68%) and an increase in the contents of P (107%), K (112%) and particularly Na (133%). Ca and Mg were affected to a lower degree. In the alternative N-fertilization, no decrease under 90% was detected in the concentration of all observed elements in comparison with 1993
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