Study of the spring growth of perennial ryegrass cultivars in relation to heat sums.

摘要

In 1991-92, biomass production, growth rate and heat sums from 1 February were determined in swards of 6 perennial ryegrass [Lolium perenne] cultivars growing in the Belgian Ardennes. There was a significant difference in growth rate between 3 early-maturing and 3 late-maturing cultivars, with average growth rates ranging from 9.5 to 12.7 kg dry matter (DM) day-1 ha-1 and from 6.2 to 6.6 kg DM in 1991 and 1992, respectively. Harvestable biomass of 1.50 t/ha was given by the earliest cultivar, Bastion, after 434 and 482 degree-days in the 2 years compared, with 580 degree-days in the latest cultivar, Barenzia; this was equivalent to 10-15 days at an average temperature of 10degC.