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The agronomic performance of Caucasian clover in high country grasslands was the subject of two experiments at Lake Heron Station, Canterbury. In the first experiment, Caucasian clover was direct drilled into an undeveloped pasture (soil pH = 5.5; Olsen P = 7 mg/ litre) with fertilisers containing similar P and S but ± 20 kg/ha of N, in December 2011. After 11 months, shoots of Caucasian clover were small (3 mg), indicating an inoculation failure, and effects of fertilisers were not biologically meaningful. Therefore, the influence of rhizobia inoculant, superphosphate and lime on early growth of Caucasian clover was assessed using the same soil in a glasshouse. Un-inoculated plants were 13-24% the size of inoculated plants and this lack of vigour was not overcome by fertilisers. In the second field experiment, an established Caucasian clover/ browntop pasture (soil pH = 5.5; Olsen P = 5 mg/litre) received 0, 100, 200 and 400 kg/ha of superphosphate with 0 or 5 t/ha of lime in February 2012. Despite the high inputs, spring pasture yields 9 and 21 months after fertiliser application were low (1260-2400 kg DM/ ha), but the contribution of Caucasian clover was high (66-76%). Keywords: high country, nitrogen, phosphorus, Trifolium ambiguum

Dry matter (DM) yields, botanical composition, liveweight production and pasture quality of six grazed dryland pastures established in 2002 at Lincoln University, Canterbury, are reported for Years 6 (2007/08) and 7 (2008/09). Lucerne (Medicago sativa) yielded 14.0 t DM/ha/yr and sheep liveweight (LW) production totalled 903 (2007/08) and 1 141 kg/ha/yr (2008/09). Metabolisable energy (ME) on offer (~134 GJ/ha/yr) and N yield (>500 kg/ha/yr) from the lucerne exceeded those of grass-based pastures. Yields (9.8- 11.2 t DM/ha/yr) and liveweight production (814-912 kg/ha/yr) from cocksfoot (Dactylis glomerata) pastures established with subterranean (Trifolium subterraneum) clover were greater than all other grass-based pastures. Annual ME was 79-96 GJ/ha and N yield was 269- 316 kg/ha from the cocksfoot, subterranean clover and volunteer white clover (T. repens) components. For Year 7, the contribution of unsown weeds and grasses in cocksfoot-based pastures was ~28% of total annual yield compared with 55% in ryegrass (Lolium perenne)/ white clover pastures. Consequently, the ME and N yields from sown pasture components in ryegrass/white clover pastures were lower than those from cocksfootbased pastures. These results indicate dryland farms with lucerne and/or cocksfoot/sub clover pastures can produce higher DM yields from more persistent pasture species. Persistence led to more ME and N on offer to grazing livestock, which resulted in higher liveweight production than from the ryegrass pastures. Keywords: balansa clover, Caucasian clover, growth rates, pasture quality, T. ambiguum, T. michelianum

The water use efficiencies (WUE) of a range of temperate pasture species were calculated from measurements on several different dryland and irrigated pastures in Canterbury. The annual WUE ranged from 6.7 kg DM/ ha/mm for a dryland cocksfoot pasture to 40 kg DM/ha/ mm for a dryland lucerne crop grown on a Wakanui silt loam soil. Keywords: Cichorium intybus, Dactylis glomerata, Lolium perenne, Medicago sativa, Trifolium ambiguum, T. michelianum, T. pratense, T. repens, T. subterraneum

Autumn sowing on 4 February (SD1) and 31 March (SD2) 2000 was used to compare the establishment success of white and caucasian clovers sown with 0, 3, 6 or 12 kg seed/ha of perennial ryegrass. Total dry matter (DM) production from sowing to 3 October 2000 averaged 5770 and 3470 kg DM/ha for the two sowing dates, respectively. Clover species did not affect herbage production in monocultures which averaged 2610 kg DM/ha. The total DM increase from the addition of ryegrass was 87, 109 and 114% for 3, 6 and 12 kg/ha, respectively. On 3 October 2000, white clover content averaged 15% when sown with 3-12 kg/ha ryegrass on SD1 but less than 2% for SD2. Caucasian clover never exceeded 9% in either sowing and weed content was 2% when ryegrass was included for SD1 but 18% for SD2. A complimentary controlled environment study examined seedling development and growth of the three species. For each species the leaf appearance interval (phyllochron) in days differed across temperatures but was constant in thermal time at 94ºCd for white clover, 109ºCd for caucasian clover and 101ºCd for ryegrass. Axillary leaves and tillers of ryegrass first appeared after 375ºCd compared with 439ºCd for axillary leaves of white clover and 532ºCd for stolon initials. No secondary leaf development or rhizome initiation was detected in caucasian clover up to 774ºCd. At this time ryegrass seedling shoots were 635 mg/plant compared with 167 and 184 mg/plant for white and caucasian clovers, respectively. Thus, the success of ryegrass seedlings during autumn pasture establishment was explained by its high relative growth rate, and rapid onset of axillary leaf and tiller development compared with white and particularly caucasian clovers. Successful caucasian clover establishment is most likely to occur in the absence of either ryegrass or white clover. Keywords: axillary shoots, Lolium perenne, pasture establishment, phyllochron, sowing date, sowing rate, thermal time, Trifolium ambiguum, Trifolium repens

The N2 fixation ability of caucasian clover was compared with that of white clover in irrigated ryegrass pastures over years 2 and 3 of a grazing experiment, using the 15N enrichment technique. 'Endura' caucasian clover was inoculated with the specific Rhizobium strain ICC148. The N concentration in clover herbage and the proportion of clover N derived from N2 fixation (PN) were similar for both clovers at averages of 4.6%N and 50-60% respectively over the 2 years. The amount of N2 fixed per hectare was directly related to the amount of clover dry matter (DM) produced by the two clover species. Caucasian clover produced four times the DM yield of white clover in year 2 (5400 cf. 1450 kg DM/ha) and four times the amount of N2 fixed in herbage (136 cf. 36 kg N/ ha). In year 3, caucasian clover produced 50% more clover DM (3450 cf. 2370 kg DM/ha) and N2 fixed (98 cf. 66 kg N/ha) than white clover. The increased N input from caucasian clover increased grass %N and N uptake from soil in caucasian clover pastures resulting in higher total pasture production compared with white clover pastures (15.7 cf. 14.2 t DM/ha) by year 3. In this study, caucasian clover demonstrated greater potential than white clover to meet the N demands of high-yielding perennial ryegrass in an intensive pastoral system. Keywords: clover content, Lolium perenne, nitrogen fixation, pasture production, Trifolium ambiguum, T. repens

Slow-establishing, high quality, pasture species are frequently added to standard ryegrass-white clover seed mixtures in an effort to improve pasture nutritive value. However, intense competition during establishment can suppress these species. Four alternative sowing strategies (Treatment 1: temporal separation of species (clovers sown in November 1998 before ryegrass direct-drilled at 10 kg/ha in March 1999); Treatment 2: substitution of ryegrass with slower-establishing timothy; Treatments 3 and 4: physical separation (alternate drill rows) of slower-establishing species from lower than average ryegrass seeding rates (3.5 kg/ ha or 8 kg/ha)) were used on a commercial North Otago dairy farm. Total dry matter (DM) production after 16 months was greater from pastures initially sown with ryegrass (19.1 t DM/ ha) (Treatments 3 and 4) than when ryegrass sowing was delayed or substituted with timothy (15.2 t DM/ha) (Treatments 1 and 2). The percentage of red plus white clover was similar in all pastures at 16 months of age and averaged 54%, compared with less than 1% for caucasian clover. Timothy sown without ryegrass contributed 42% of production (Treatment 2), compared with 7% when sown with ryegrass (Treatments 3 and 4). Ryegrass composition was similar (43%) regardless of sowing rate (Treatments 3 and 4) and sowing date (Treatment 1). This on-farm study demonstrated successful establishment of red and white clover in all four treatments but timothy and caucasian clover were suppressed by the inclusion of low rates of ryegrass. Keywords: botanical composition, competition, dry matter production, Lolium perenne, Phleum pratense, seeding rates, Trifolium ambiguum, T. pratense, T. repens

The potential of caucasian clover to improve the legume content of lowland New Zealand pastures should result in enhanced animal performance. Liveweight gains from eight flocks of ewe lambs rotationally grazing irrigated ryegrass pasture with caucasian or white clover at two levels of soil fertility (Olsen P values 10 or 22) were compared during years 2 (1998/1999) and 3 (1999/2000) of an ongoing grazing experiment in a lowland environment. Clovers were sown in December 1996 and ryegrass in March 1997 into the pure clover swards. Lamb liveweight gains were similar in year 2 (1130 kg/ha/yr), but in year 3, gains were greater on pastures sown with caucasian than on those sown with white clover (1290 vs. 1110 kg/ ha/yr). Spring liveweight gains per head per day averaged 170 g/hd/d in year 2, and in year 3 were greater from caucasian than white clover pasture (180 vs. 160 g/hd/d). Caucasian clover pastures had more legume on offer than pastures sown with white clover in year 2 (26% vs. 17%) and year 3 (19% vs. 12%). In year 3, 39% of the total legume on offer in caucasian clover pastures was volunteer white clover. Soil fertility had little influence on results. Early years of this grazing experiment showed that caucasian clover can establish as well as white clover if sown alone, and that sowing caucasian clover can result in lowland pastures with an increased total legume content which may improve liveweight gains. Keywords: legume content, Lolium perenne, pasture production, sheep liveweight gain, Trifolium ambiguum, T. repens

Seedlings of KZ2 caucasian clover (Trifolium ambiguum) were grown at 4 sites within New Zealand (Kerikeri 36°S, Palmerston North 40°S, Lincoln 43°S and Gore 46°S) where they received natural daylight and temperatures during 1997. Northernmost plants produced more vegetative primary crown shoot buds than southernmost. In the first growing season numbers of flowering shoots formed per plant were: K 17.9, P 10.0, L 10.2 and G 5.7. In spring of the second growing season, mean numbers of primary crown flowering shoots per plant at peak flowering in December 1997 were: K 19, P 30, L 55, G 20. Fewer flowering shoots formed at upturned rhizome tips. Daylength was not the major factor controlling flowering, the results instead supporting the hypothesis that low temperatures provided the main flowering stimulus. Lincoln was the best of the four locations overall for flowering shoot production. Fewer flowering shoots at Gore probably resulted from slower growth in cooler conditions. Poorer flowering at Kerikeri in the second season might have resulted from the warmer northern winter or been linked to the overproduction of vegetative buds in the first season. Stronger flowering at Kerikeri during the first season raises the possibility, though, of growing caucasian clover as an annual crop for seed production in Northland if sown early in spring. Keywords: caucasian clover, daylength, flowering, low temperature, seed production, Trifolium ambiguum

Hexaploid caucasian clover (Trifolium ambiguum) was one of the components of a 25-species pasture mixture overdrilled into hieracium-infested fescue tussock grassland. The mixture was subjected to 60 different annual sulphur and phosphate fertiliser rate, stocking rate, and stocking method treatments for 16 years. Caucasian clover was slow to establish but increased to become the dominant species in the pastures under high fertiliser inputs after a decade, but only a minor species at lower inputs. Keywords: fertiliser, grazing management, high country, Trifolium ambiguum

Caucasian clover (Trifolium ambiguum M. Bieb.) is an alternative legume for areas where white clover (T. repens L.) growth is limited. However, slow establishment has been a problem when caucasian clover has been oversown. Results from two tussock grassland sites have demonstrated the importance of the initial establishment of caucasian clover. Caucasian clover dry matter production after 6 years was still related to original seedling establishment. This result was obtained in ungrazed swards, conditions likely to maximise the ability of caucasian clover to spread by rhizomes and natural reseeding. The results indicate that caucasian clover may make little contribution to legume yield in these environments for at least 6 years unless satisfactory numbers of plants are established initially. Maintenance fertiliser application, in early years at least, appears similar to that required by white clover. Yields of caucasian clover swards in the 6th year when maintenance fertiliser had been applied were 3-7 times those when fertiliser had been applied only at sowing. The paper also provides possible explanations for establishment failures that have already occurred, and provides information on correct management techniques to maximise establishment of oversown caucasian clover. Keywords: caucasian clover, establishment, fertiliser, hill country, inoculation, nodulation, oversowing, pasture, Trifolium ambiguum

Caucasian clover (CC) and white clover (WC) pastures were established on a Bay of Plenty dairy farm in September 1994 and undersown with ryegrass (RG) in July 1995. Yields of mown RG- CC plots surpassed those of RG-WC plots from December to April in the second year after establishment (1995/96), producing 1362 kg (26%) extra DM/ha during this period. In 1996/97 yields of RG-CC plots surpassed those of RG-WC from October to April, producing 1531 kg (43%) extra DM/ha in December-April. In grazed RG-CC plots during December-May 1996/97, RG yields were slightly reduced (371 kg/ha, -12%) in comparison with RG-WC plots, and extra production resulted from greatly increased total legume yield (2155 kg/ha, 187%). Pasture legume content during summer-autumn averaged 24% for RG-WC and 54% for the RG-CC pastures. The superior performance of CC over WC appeared to relate to its protected underground growing points, and taproot retention, facilitating better pasture cover during summer, and greater tolerance of pests including grass grub and clover cyst nematode. Caucasian clover shows promise as a perennial legume which may offer improved availability of high quality forage at a time of year when clover growth is often insufficient for good animal performance. Caucasian clover clearly has potential in northern as well as southern regions of New Zealand. Keywords: dairy pasture, Lolium perenne, northern New Zealand, pasture pests, Trifolium ambiguum, Trifolium repens

Caucasian clover (Trifolium ambiguum M.Bieb) representing a range of 2x (diploid), 4x (tetraploid) and 6x (hexaploid) material together with ecotypes from the Caucasus region were established in a trial at Lincoln, Canterbury (43"38'S) in October 1993. Measurements were made from individual plants during summer 1994-95. The diploids were earliest to flower followed by the tetraploids and finally the hexaploids, which reached peak flowering in mid December. The hexaploids produced the most florets per inflorescence (115, 101, 96 from 6x, 4x, 2x respectively), the most inflorescences per plant (162, 101, 129 from 6x, 4x, 2x) and the highest seed yield(g) per plant (26, 9, 11 from 6x, 4x, 2x). There was large variation for all the seed production components within the three ploidy levels. For example, the hexaploid cultivar Endura consisted of plants that varied from 25-510 inflorescences per plant. The seed yield components of plants were associated with active spring growth. There was evidence of wide spreading plants producing lower numbers of -inflorescences-per-m2-andseed-yield-per-unit-area; The hexaploid material produced the greatest potential seed yields (1330,685, 1000 kg/ha from 6x, 4x, 2x respectively). There was a 5-fold difference between the lowest-yielding 6x cultivar, Prairie (570 kg/ha), and the highest-yielding KZ2 (2720 kg/ha), a selection from Monaro. Major gains are possible through selection but it is important to select for improved seed yield per plant (not just flowers) and to maintain a wide genetic base. Commercial crops yield approximately half that attained from research plots, whtch suggests a commercial yield of 900 kg/ha is possible from Endura. This compares favourably with other legumes but requires development of crop management practices that ensure consistently high seed yields. Keywords: Caucasian clover, genetic variation, Kura clover, seed components, seed yield, TrifIium ambiguum

Hexaploid Trifolium ambiguum M. Bieb. (Caucasian clover cv. Prairie) persisted and dominated in high country plots which received more than 100 kg P/ha at establishment. After 13 years the biomass of coarse roots (rhizomes and tap-roots) amounted to 20 t/ha. The contents of nutrients in the root fractions were approximately five times that in the herbage. This ability to retain nutrients in coarse roots may be a strategy that contributes to the dominance of Caucasian clover on this acid soil. Keywords: nutrients, phosphorus, roots, Trifolium ambiguum