The Growth Responses of Lolium perenne to the Weather During Winter and Spring at Various Altitudes in Mid-Wales

Abstract

The seasonal growth patterns of micro-swards of a single genotype of L. perenne cv. S.23 were studied at 4 sites at various altitudes in mid-Wales [United Kingdom] from Oct. 1973-July 1974. Upland sites were 1.5-2.5.degree. C cooler and received 2-16% less insolation than lowland sites. The seasonal patterns of leaf dry matter production by single vegetative tillers at the 4 sites was largely controlled by temperature. Leaf extension at all sites was consistently related to soil temperature. Leaf extension at a given temperature was faster in the spring than in the autumn. Leaf appearance rate at a given temperature was greater in the spring than in the autumn and was greater in upland than in lowland sites. Even in winter there was a considerable turnover of leaf material because as new leaves appeared old ones were lost. Tillering rates were generally greatest at lowland sites and were greatest during early April to early May. Tillering rate was low or negative in winter. If the final autumn cut was made in Oct., as opposed to Sept., leaf extension, leaf length and leaf weight were reduced by about 1/5 over the following 6 mo., and tillering in the autumn was reduced, though tillering in the following spring was increased.