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The reclamation of bracken‐dominated pastures in Bulgaria using asulam and fertilizers
Author(s) -
Petrov P.,
Marrs R. H.
Publication year - 2001
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1046/j.1365-2494.2001.00258.x
Subject(s) - agronomy , bracken , dactylis glomerata , holcus lanatus , pteridium aquilinum , festuca rubra , poa pratensis , perennial plant , fertilizer , phosphorus , grassland , lolium perenne , weed , biology , environmental science , chemistry , botany , poaceae , fern , organic chemistry
Bracken ( Pteridium aquilinum ) is a major weed of considerable economic concern in upland pastures in Bulgaria and elsewhere in Europe. Between 1993 and 1998, a field experiment was carried out to test methods for restoring productive meadows. Initially, spraying asulam (4·8 kg a.i. ha −1 ) was used to control the bracken on the site; this was achieved in terms of reduced frond densities and a higher level of grassland establishment. This grassland was dominated by Vicia cassubica and the perennial grasses Agrostis vulgaris , Dactylis glomerata , Festuca rubra , Holcus lanatus and Poa pratensis . After 2 years, a fertilizer addition experiment was started with four treatments (no fertilizer; addition of phosphorus; addition of nitrogen and phosphorus; addition of nitrogen, phosphorus and potassium. The phosphorus and potassium fertilizers were applied annually in the early spring at 80 kg of P ha −1 year −1 and 50 kg of K ha −1 year −1 , and nitrogen was added at the start of grass growth at 60 kg of N ha −1 year −1 . At the same time, a twice‐yearly hay‐cutting regime was implemented. Fertilizer addition increased both the quantity and the quality of the resulting grassland. The herbage dry matter was increased by at least a factor of two depending on fertilizer combination, and there was an increase in grass and legume cover and a decrease in both weed cover and bracken recovery. However, although bracken recovery was inversely related to grassland production, there was a consistent increase in bracken density across all treatments between 1997 and 1998, suggesting that increasing herbage biomass merely delays bracken recovery. The implications of these findings are discussed.