1. Impact of spatial heterogeneity of plant species on herbage productivity, herbage quality and ewe and lamb performance of continuously stocked, perennial ryegrass-white clover swards.
- Author
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Sharp, J. M., Edwards, G. R., and Jeger, M. J.
- Subjects
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PLANT species , *ENVIRONMENTAL impact analysis , *GRASSES , *RYEGRASSES , *WHITE clover , *EXPERIMENTAL agriculture - Abstract
The benefits of white clover ( Trifolium repens L.) in pastures are widely recognized. However, white clover is perceived as being unreliable due to its typically low content and spatial and temporal variability in mixed (grass-legume) pastures. One solution to increase the clover proportion and quality of herbage available to grazing animals may be to spatially separate clover from grass within the same field. In a field experiment, perennial ryegrass ( Lolium perenne L.) and white clover were sown as a mixture and compared with alternating strips of ryegrass and clover (at 1·5 and 3 m widths), or in adjacent monocultures (strips of 18 m width within a 36-m-wide field). Pastures were stocked by ewes and lambs for three 10-month grazing periods. Over the 3 years of the experiment, spatial separation of grass and clover, compared with a grass-clover mixture, increased clover herbage production, although its proportion in the sward declined through time (0·49-0·54 vs 0·34 in the mixture in the first year, 0·28-0·33 vs 0·15 in the second year and 0·03-0·18 vs 0·01 in the third year). Total herbage production in the growing season in the spatially separated treatments decreased from 11384 kg DM ha−1 in the first year to 8150 kg DM ha−1 in the third year. Crude protein concentration of clover and grass components in the 18-m adjacent monoculture treatment was greater than the mixture treatment for both clover (310 vs 280 g kg−1 DM) and grass (200 vs 180 g kg−1 DM). There was no clear benefit in liveweight gain beyond the first year in response to spatially separating grass and clover into monocultures within the same field. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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