A small‐plot experiment was carried out with grass‐lotus (Lotus spp.) swards on a lowland (185 m) clay‐soil site in S‐W England. Two species of lotus (Lotus corniculatus cv. Leo and L. pedunculatus, syn, L. uliginosus, cv. Maku) were each sown at 10 kg seed ha−1 with lour grass species each at two grass‐seed rates: Festuca pratensis at 6 or 3 kg ha−1 and Phleum pratense, Agrostis capillaris and Poa pratensis at 4 or 2 kg ha−1. Assessments were made over three harvest years (1992–94). during which no fertilizers were applied. Mean total herbage dry matter (DM) harvested from cv. Leo swards was 90 t ha−1 in year 1, 8–9 t ha−1 in year 2 and 4 0 t ha−1 in year 3. and from cv. Maku swards 6–6 t ha−1 in year 1. 8–9 t ha−1 in year 2 and 3–9 t ha−1 in year 3. Highest three‐year mean total yields were with F. pratensis as the companion grass (7–4 t ha−1 year−1), followed by Phleum pratense (7–0 t ha−1), A. capillaris (6–9 t ha−1) and Poa pratensis (6–2 t ha−1). The lower grass‐seed rate resulted in a greater proportion of lotus in the total harvested DM in year I. The higher grass‐seed rate resulted in higher yields from F. pratensis swards in year 1, but there were no significant effects for other species or in subsequent years. Lotus as a proportion of harvested DM declined from about 70% in year 1 to about 20% in year 3. The mean DM yield of lotus herbage in years 1, 2 and 3, respectively, was 5–5, 2–8 and 0–8 t ha−1 from cv. Leo swards, and 4–0, 3–3 and 0–8 t ha−1 from cv. Maku swards. Lotus herbage was of higher digestibility from cv. Leo [digestible organic matter (DOM) of 661 g kg−1 of lotus DM] compared with cv. Maku (551 g kg−1 DM). Mean N content of lotus herbage was 35 g N kg−1 DM. Digestibility of companion grass herbage was highest for Phleum pratense (557 g kg−1 DM) and lowest for A. capillaris (493 g kg−1 DM). It is concluded that lotus may be an alternative legume to white clover for low‐input, low‐fertility situations. However, further research is needed to evaluate its performance on different sites and under different management regimes, particularly grazing, and to overcome the apparent problems of its persistence.

Two experiments, each lasting approximately 12 months, were carried out at North Wyke, Devon, in 1982-83 (A) and 1983-84 (B), to investigate various sward managements following oversowing of white clover {Trifolium repens, cv.

The effects of cutting frequency on dry matter yield, crop persistence and herbage quality of representative diploid and tetraploid varieties of broad red clover (Trifolium pratense) were investigated in two trials at Hurley in the period 1975-79.Pure-sown swards of broad red clover varieties were used in the first trial (A), while both puresown swards and those sown with a perennial ryegrass companion grass were included in the second trial (B).Trial A was cut three or six times per annum, trial B three, four or five times per annum. In both trials, the change from normal management of three cuts per annum to six (trial A) or five (trial B) cuts per annum reduced output, whether in terms of dry matter yield (trial A by 31%; trial B by 33%), N yield (trials A and B by 15%) or metabolizable energy (trial A by 24%; trial B by 28%), and in trial A also led to more rapid reduction in clover plant density. More frequent cutting also raised mean D-value (trial A by 5-3 units; trial B by 3-4 units) and N concentration (trial A by 6 4 g kg dry matter"'; trial B by 70 g kg dry matter"')• Tetraploid (4x) red clover varieties generally out-yielded diploid (2x) varieties, except in trial A in 1976 when, under drought conditions, Granta and Kuhn (both 2x) equalled the yield of Wensum (4x) and out-yielded Norseman and Maris Leda (both 4x).The companion grasses included in trial B formed a sequence from early to late flowering (Aberystwyth S24, Barlenna, Endura), and their inclusion raised dry matter yields and D-value, though it lowered N concentration in the mixed herbage. Highest annual dry matter yields in this trial, which received supplementary irrigation, were 16 41 ha~' from a pure-sown crop (Hungaropoly) and 20 5 t ha~' from a mixture (Wensum/ Aberystwyth S24), from three cuts in the first harvest year. Aberystwyth S24 had the greatest effect in raising yields; though least effect on improving digestibility. Endura was the converse, and it was concluded that an intermediate-maturity variety such as Barlenna was the most satisfactory companion.Both trials A and B suggested that in south-east England, broad red clover can be considered only as a 2-year crop and that ways must be found to prolong its productive life. Strategies to increase the digestibility and hence the economic value of the crop by cutting more frequently than three times per year are unattractive because of the large fall in yield and relatively small improvement in digestibility and hence metabolizable energy concentration.

A small-plot cutting trial was carried out 1983-85 at North Wyke Research Station, Devon to compare the dry matter (DM) production and response to nitrogen (N) of a naturally occurring Agrostis stoloniferadominant sward, developed under low fertility conditions on a poorly structured soil, and a sward of Lotium perenne cv. Melle, directdrilled in 1982 at the same site. All plots received standard inputs of P, and graded inputs of K, related to the four annual N treatments (0, 200, 400 and 800 kg ha"', in seven equal applications). All plots were cut six times each year, except in 1983; DM yield, herbage digestibility, herbage N concentration, response to applied N, apparent recovery of applied N, and botanical composition of the swards were recorded.On average, A. stolonifera gave 69% of the DM yield of L. perenne. A. stolonifera did not out-yield L. perenne at the low N levels (0 or 200 kg N ha"' a"'), or in mid-season, and yielded significantly (P<0-001) less in drought conditions in 1984 (4-4 t DM ha"' and 6-9 t DM ha" ', s.e.d.±0-22). Average digestibility of A. stolonifera was 3 units of D-value lower (P<0-001) than L. perenne, but N concentrations were higher (3-Ol<7o and 2-53'?'o, s.e.d. ±0-074). However, total yields of N froni A. stolonifera were lower. Responses in DM production per kg N applied were lower in

Plots of a 2-year-old sward of Merlinda perennial ryegrass received a routine dressing of 100 kg N ha^' as compound fertilizer in March 1991, followed by further dressings of 100 kg N ha"' after cuts 1,2 and 3 in a simulated four-cut silage system, either the same day as cutting or with a delay of 3, 7, 10 or 14 d. Partial irrigation ensured that fertilizer could be taken up immediately. Annual total dry matter yield, the dry matter yield for the experimental cuts 2-4 and their apparent response to N showed no effect of delays of O-IO d in reapplication of fertilizer, but a significant {P < 0-01) reduction for 14 d delay. Significantly {P = 0-001) higher apparent recovery of N in the cut herbage was recorded where reapplication of fertilizer had been delayed by 7 or 10 d (93% and 91% respectively) in comparison with either smaller (0 delay, 78%; 3 d delay. 87%) or greater delay (14 d, 86%). It is suggested that lower recoveries at 0 and 3 d result from the sward's reduced NOj uptake following defoliation and that, while in practical situations the conditions may not be as rigorous as those imposed in this experiment, further experiments to determine the fate of N not recovered in the herbage are warranted, so defining management circumstances in which immediate reapplication of N might not be advisable.