Seed development of red clover in mixed-sown meadows: model predictions

Abstract

It is important to understand the effects of meadow management on the demography of red clover ( Trifolium pratense L.) for the sustainable yield of forage in permanent mixed-sown meadows. To clarify the reproduction probability of red clover in meadows for herbage cutting, the seed development of this legume is predicted using a model, the components of which are flowering rate, seed set proportion and seed ripening proportion. These rate and proportions are determined by monitoring the numbers of florets and seeds in mature plants transplanted from a mixed-sown meadow and cut at the same time in the meadow. The predictions are as follows: red clover would produce viable seeds from late July to late August, 28% of the florets would become viable seeds, the setting of viable hard seeds would be delayed by 1 week compared with that of viable permeable seeds, and there would be a peak in the number of permeable seeds in mid-August when the ratio of the number of permeable seeds to that of hard seeds would be 1:1. The predictions are partly validated with a seed trap experiment: many red clover seeds were captured immediately after the second haymaking in mid-August when the ratio of the density of permeable seeds to that of hard seeds was approximately 1:1. The model suggests that the time of the second haymaking affects the numbers of deposited permeable seeds and hard seeds of red clover. Permeable seeds and hard seeds are expected to emerge as seedlings in the autumn of the present year and in the spring of the succeeding year, respectively, in the meadow.