WEATHER FLUCTUATIONS AND DAILY RATE OF GROWTH OF PURE STANDS OF 3 GRASS SPECIES

Fluctuations in the growth rates of pure stands of perennial and short-rotation ryegrass and cocksfoot attributable to daily changes in weather factors were determined during five periods of the year. The technique of measurement included replication in time as well as space. Marked differences in seasonal growth rates obtained were attributable to seasonal changes in temperature, light, and rainfall. Significant correlations were also obtained between daily fluctuations in growth rate of the species and short-term (daily) changes in weather. Time-lag correlations of as much as 4 days were also shown for some of the weather factors. Fluctuations in growth rate attributable to components of the daily weather were generally of a greater magnitude than growth increments attributable to smoothly changing weather in each experimental period. The results are discussed in terms of the relative importance of the various weather factors on growth in this environment and of the length of the periods of adaptation required before changes in weather factors are expressed as changes in dry matter increments in the field. The technique of measurement is also assessed. © 1969 Taylor & Francis Group, LLC. All rights reserved.