Assessing seed priming, sowing date and mulch film to improve the germination and survival of direct sown Miscanthus sinensis in the UK

Direct sowing of Miscanthus seed could lower crop establishment costs, increase the rate of grower uptake and biomass supply for the emerging bio‐economy. A replicated field trial was conducted at two contrasting UK sites: Aberystwyth (ABR) in mid‐Wales and Blankney (BLK) in Lincolnshire. These sites encompass the West‐East meteorological gradient in the UK where the growing season at ABR is cooler and wetter whilst BLK is warmer and drier. Primed and unprimed M. sinensis seeds were sown directly onto the soil surface with and without a clear bio‐degradable mulch film, at nine dates interspersed from May to October. Average daily mean soil surface temperatures measured over the first two months after sowing under the mulch film were higher than control plots (2.7°C ABR and 4.2°C BLK). At both sites the film covering also affected soil volumetric moisture relative to uncovered control plots (‐3% ABR and 8% BLK) demonstrating the negative impact of mulch film when sowing on dry soil. Over nine sowings, seed germination at ABR under film varied between ‐28% to +18% of germination under control conditions. Seedlings from the first three sowings at both sites under film had sufficient physiological maturity to survive the first winter period. At BLK, mulch film significantly increased tiller count and height in both the first and second year after sowing. At ABR, where temperatures were lower, film covering significantly increased tiller height but not count. Water priming had no significant effect on seed viability or germination in the field tests. Base temperatures for germination of primed and unprimed seed on a thermal gradient plate were 7.0°C and 5.7°C respectively with a ±1.7°C confidence interval. Based on our results for M. sinensis in the UK we recommend the sowing of unprimed seed in May under film and only when the soil is moist