Vertical rhizome disking to reduce Elymus repens (quackgrass) abundance in grass-clover leys

Elymus repens is a problematic perennial weed in annual crops, grasslands and leys. Rhizome fragmentation by vertical disking can potentially reduce E. abundance with minimal tillage, but data are lacking on its efficiency forage production. In two-year study (2017–2018, 2018–2019) conducted two grass-clover leys that were mostly weed-free except for large populations, this examined effects yield, botanical composition, rhizome biomass of at significant growth initiation spring (early fragmentation, ERF) and/or when conditions allowed after the first cut (late LRF). Cold, wet springs hard, dry soil summer delayed treatment both years, to late (ERF) summer/early autumn (LRF). year, ERF reduced first-cut yield 44% compared no while LRF decreased second- third-cut 24% 53%, respectively. year treatment, increased total average 10%, had effect. Over combined was 11% 4% LRF. Both treatments biomass, inconsistently (ERF 25% one only, sites). incidence 10% effect following year. Thus, leys, inconsistent be impaired, especially swards much repens. Moreover, hampered conditions.