Effects of herbicide application to control sward composition in different management variants.

Herbicide application on permanent grassland to reduce weeds and improve forage quality is common agricultural practice. However, it still remains unclear how long it takes for the herbicide-disturbed swards to recover in terms of yield and forage quality. In a removal experiment in the Solling Uplands (Germany), the sward composition of permanent grassland had been manipulated by herbicides in order to obtain either relatively pure grass swards or swards with comparatively large amounts of forbs and legumes, in addition to untreated control swards. The short-term resilience of these sward types was examined under a gradient of management intensity regulated by both cutting regime and fertilizer supply. In the next growing season, the yield did not differ among any of the three sward types regardless of the management regime. All disturbed swards showed a complete recovery in terms of biomass. Yield was only influenced by functional sward characteristics across all disturbance treatments; the growth form of the dominant species determined the yield in fertilized plots. For the variation in forage quality (crude protein, water-soluble carbohydrates and fibre content), the functional group identity of the remaining vegetation was important, but management had a much larger influence than vegetation. [ABSTRACT FROM PUBLISHER]