The effects of clover variety, cutting interval and nitrogen application on herbage yields, proportions and heights in perennial ryegrass‐white clover swards

Abstract

Six varieties of white clover, each grown with perennial ryegrass, four intervals between cuts and two levels of applied nitrogen in all combinations, were compared in a field experiment during the first 27 months after sowing.Increasing the interval between harvests from 3 or 4 to 8-12 weeks increased the yield of white clover and generally did not reduce the proportion of clover in total herbage. Increasing the interval between harvests reduced the number of grass tillers but increased grass yield and the size of grass leaves and increased grass height more than clover height; it also increased the proportion of petiole relative to leaflet in the clover. Differences between varieties in response to interval between harvests were small but supported the view that medium large-leaved varieties can with advantage be defoliated rather less frequently than small-leaved ones. The adverse effect of applied N on clover appeared almost equally great with all four intervals between harvests and further research on this topic is suggested. Applied N increased grass height more than clover height and increased the number of grass tillers, the size of grass leaves and grass yield. The medium large-leaved varieties seemed more tolerant of applied N than the smaller varieties.

Digestion kinetics of leaf, stem and inflorescence from five species of mature grasses

“…19 The changing proportions of ryegrass leaf, stem and flower and their nutritive value have been reported previously. 20 Stem DM increased to over 60% of the DM, whereas green leaf declined to very low levels. The in vitro digestibility of leaf declined by a small amount as grass matured (from 64 to 58%) whereas stem was 49% digestible when mature.…”

The effects of variety, cutting interval and nitrogen application on the morphology and development of stolons and leaves of white clover

“…The experimental treatments, many of the procedures and the weather have been described previously (Wilman and Asiegbu, 1982). The experimental treatments comprised all combinations of six varieties of white clover, four intervals between harvests and two levels of applied N. A randomized-block design was used, with two blocks each of forty-eight plots.…”

“…The number of clover leaves harvested was counted in the herbage samples taken for separation into botanical fractions (Wilman and Asiegbu, 1982). The number of leaves harvested as a percentage of the number in the sward in Table 8 was derived from the total number harvested from each plot in 1977 and the total number counted on each plot in that year.…”

“…In an earlier paper (Wilman and Asiegbu, 1982) we have considered the effect of white clover variety, interval between harvests and N application on yields of white clover {Trifolium repens) and total herbage, the proportion of crop fractions in clover and the heights of clover and grass in a field experiment. In the same experiment we recorded stolon length and diameter, petiole length and numbers, weights, emergence and death of leaves in order to better understand the response of the clover to the various treatments and to changing weather.…”

“…Information about yields, crop fractions, heights and ryegrass tillers has been presented in an earlier paper (Wilman and Asiegbu, 1982). The present paper is concerned with the more detailed studies of white clover, which help to explain the yield results and contribute to the understanding of the response of this species to management when grown in competition with grass.…”