The effect of grazing versus cutting on dry matter production of multispecies and perennial ryegrass‐only swards

Abstract

Dry matter (DM) production of multispecies swards compared to perennial ryegrass (Lolium perenne; PRG) swards under intensive grazing warrants investigation as it is relatively unknown. A 5 × 2 factorial experiment, with five sward types and two defoliation methods, was used to investigate the effect of grazing versus cutting on dry matter (DM) production of multispecies and PRG‐only swards. Five sward types were established namely: a PRG‐only sward, receiving 250 kg N ha−1 year−1 (PRG250), and a PRG‐only sward (PRG90), a two‐species sward with PRG and white clover (Trifolium repens; PRGWC), a six‐species sward (6S) and a nine‐species sward (9S), each receiving 90 kg N ha−1 year−1. Cutting plots measured 1.95 × 10 m and grazing plots measured 10 × 10 m. All plots were harvested concurrently every 21–30 days from April‐November for two years (2015 and 2016). A strip from the grazing plots was cut for DM yield determination prior to turning in cattle for grazing. There was an interaction between sward type and defoliation method (p < .01), whereby there was no effect of defoliation method on the PRG‐only swards, however, the annual DM production of PRGWC, 6S and 9S swards reduced under grazing compared to cutting (p < .001; on average 1,929 kg DM/ha lower). Multispecies swards had lower DM production under grazing compared to cutting, while the DM yield of PRG‐only swards was unaffected by defoliation method.

Dry‐matter production and botanical composition of multispecies and perennial ryegrass swards under varying defoliation management

“…Higher DM production was achieved from MSS at lower chemical N inputs compared to LP and at the same level of chemical N input as LP‐TR, most notably when managed on a 28‐day rotation as opposed to a 21‐day rotation. This response agrees with similar plot scale studies (Finn et al, 2013; Grace et al, 2019) reflecting multispecies swards' capacity to produce more herbage DM than less functionally diverse swards. Given the environmental and economic benefits associated with lower use of fertilizer N, the greater herbage DM production from MSS receiving 90 kg N ha −1 compared to LP receiving 250 kg N ha −1 indicates the potential of multispecies swards as a more sustainable alternative to L. perenne ‐based production systems.…”

Grassland Management Impact on Soil Degradation and Herbage Nutritional Value in a Temperate Humid Environment

“…The observed high variability in chemical composition and digestibility (Table 5) is the main characteristic of grasslands due to herbage community composition, season, soil composition, fertilisation level, growth stage and grassland management [23,28,73]. The average nutrient contents and digestibilities are within the range of values reported in the INRA dataset [74] for permanent lowland pastures in July.…”

“…Grassland management in terms of defoliation regime affects biomass production and plant biodiversity [23,24], with grazing promoting the dominance of grasses and mowing promoting the dominance of non-leguminous forbs [25]. Although changes in plant biodiversity imply changes in chemical composition, the nutritional value of herbage in grazed and mowed grasslands has not often been compared in previous studies.…”

An assessment of herbage mass, ryegrass cultivar and red clover inclusion on sward productivity, quality and morphology under a cutting protocol

“…Each treatment combination was replicated four times, meaning there were 48 plots in total with each measuring 1.1 m × 7 m (7.7 m 2 ). Plots were arranged in a completely randomized block design as per Grace et al (2019). Plots were sown on 19th September 2017 using a plot seeder (Wintersteiger, Ried im Innkreis, Austria) and the monoculture seeding rate for each of the ryegrass cultivars used was as follows: DIP = 34.6 kg/ha, TET = 39.5 kg/ha and HY = 35.0 kg/ha.…”