The phenological development of three ryegrass clones and the influence of initial silage cut on regrowth under silage management

摘要

Due to its plasticity, perennial ryegrass (Lolium perenne L.) is suitable for both silage and grazing management in the diverse ruminant livestock systems of the UK and Ireland. Plant maturity influences the temporal change in quality of forage grasses when grown under different management systems, therefore, accurate identification of the growth stages of a grass sward is critical to many forage breeding and management decisions. The decision on harvest dates in breeder, official testing systems andon-farm is largely a visual estimation of the general phenological stage of the grass crop. This two-year study evaluates the effects of five harvest dates and three clonal swards of early, intermediate and late maturating perennial ryegrass on the primary and secondary re-growth under a 3-cut silage management. Delayed harvest increased the number of developmental stages recorded during primary growth but varied for the subsequent regrowth periods. Over years analysis showed that the mean developmental stage in the clones increased duringprimary growth. The initial cut date resulted in different response curves for four growth stage classes among the clones, only at silage cuts 1 and 2.