r genotypes is unclear. To address the possibility of identifying genotypes better suited to AD or exploiting natural diversity to breed new varieties, we sought to quantify soluble sugars and starch in a diverse range of germplasm.

*Miscanthus* is usually harvested at the very end of winter (January--March in the northern hemisphere) when it is fully senesced. By this time, carbohydrates and mineral nutrients accumulated over the growing season have been remobilized to the underground rhizome, and the stems are dry (Robson *et al*., [2012](#gcbb12419-bib-0040){ref-type="ref"}; Purdy *et al*., [2014](#gcbb12419-bib-0038){ref-type="ref"}). Therefore, if carbohydrates were to be captured, the crop would have to be harvested green. This then presents a number of dilemmas; a major attribute of *Miscanthus* is its low (usually nil) fertilizer demands owing to its efficient recycling system. If the stems are harvested before nutrient remobilization has taken place, the essential nutrient elements such as nitrogen (N), phosphate (P) and potassium (K) may also be removed and will require replacement with fertilizers to restore productivity. If *Miscanthus* is harvested green, it also needs to be stored to prevent nutrient losses necessary for the AD process. Studies have now shown that *Miscanthus* can ensile well‐producing good‐quality silage but quality depends upon harvest date (Klimiuk *et al*., [2010](#gcbb12419-bib-0024){ref-type="ref"}; Whittaker *et al*., [2016](#gcbb12419-bib-0047){ref-type="ref"}). It has previously been shown that in four genotypes of *Miscanthus*, rhizome NSC had been replenished to winter levels by September suggesting that harvesting after this month may not leave the rhizome depleted of carbohydrates (Purdy *et al*., [2014](#gcbb12419-bib-0038){ref-type="ref"}). To address the implications of early harvesting on elemental nutrients, we quantified N, P and K from samples harvested in July, November--December and January over 2 years.

If harvest date was to be shifted to capture 