THE EFFECT OF AUTUMN MANAGEMENT ON WINTER DAMAGE AND SUBSEQUENT SPRING PRODUCTION OF SIX VARIETIES OF LOLIUM PERENNE GROWN AT CAMBRIDGE

Six perennial ryegrass varieties which were known to differ in winter hardiness were subjected to ten managements comprising two N rates and fire autumn cutting treatments. Autumn yields and soluble carbohydrate contents were measured, also the amount of winter damage in February and subsequent spring yields. The winter was mild, herbage damage was slight and no plant deaths were recorded, but significant differences were found between cutting treatments and varieties. The amount of winter damage increased with the length of the autumn rest period and with the degree of winter dormancy of individual varieties, indicating that natural senescence was a more important causative agent than frost action. Spring yields were affected by the amount of winter damage but there were considerable interactions between varieties and environments. The results are discussed in relation to autumn management practices, choice of variety for different locations and measurements of winter hardiness. The induction of winter dormancy by day length or low temperature reactions is considered in the breeding of varieties for maximum production in different parts of the country.