Abstract
Reduction of CO2 emissions is needed to address global warming. Miscanthus, a perennial C4 grass grown for bioenergy can contribute to carbon mitigation. For the UK, it is estimated that 1.4 million hectares of land are of sub-optimal quality for food production. If 50 % of this land was made available for Miscanthus, it would increase the current planted area of ~7000 hectares, to ~700,000 hectares. This upscaling requires innovation. This thesis explores innovations in the agronomy of clonal and seed crop establishment systems which can be upscaled to meet future demand (~30 k ha-1 y-1).Key findings:
Nodal propagation increases the multiplication factor of interspecies hybrids from 20 with rhizomes, to 120. While nodal production is useful in certain circumstances, the large expansion rates required is only possible with seed propagation, where multiplication rates range from 2000 to 3000.
Upscaling with seed-based hybrids currently requires seed-to-plug and plug-to-field establishment agronomies. Trials showed direct sowing Miscanthus seed is highly risky and wasteful of limited seed stocks. Degradable transparent plastic mulch films promoted establishment percentages of germinated seedlings and plugs but could not be used to guarantee germination in direct sown seed when sowing on dry soils.
In combination with mulch film technology, a pre-emergence herbicide mixture of Stomp AquaTM and CallistoTM efficiently controlled weeds during establishment, without damage to Miscanthus.
The yield advantage for Miscanthus covered with mulch films during the first six weeks after planting persisted in three successive spring biomass harvests. Dry matter yield in year 3 of Miscanthus covered with mulch film after planting was on average 10% higher than uncovered Miscanthus.
Evaluation of novel hybrids using multi-location trials established by plug planting proved that new intra-species hybrids produced similar yields to Miscanthus x giganteus (Mxg) (Greef, 1993) in growing seasons without significant drought periods. In locations with dry summers, where Mxg failed to produce high yields, some novel hybrids could more than double the spring harvestable yield from 4 t dm ha-1 yr-1 (tonnes dry matter per hectare per year) to 11 t dm ha-1 yr-1.
| Date of Award | 2018 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Susan Youell (Supervisor) |
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