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Lotus uliginosus Schkur. |
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Leguminosae
Synonyms Lotus pedunculatus Cav. |
Author: Dr. John Frame |
| Common names.
Greater lotus, big trefoil, marsh birdsfoot trefoil. Description. Glabrous to pubescent, long-lived perennial plant with upright or scrambling growth habit early in the season but procumbent later. Leaves are characteristically pentafoliate with two of the leaflets at the base of petiole resembling stipules. The leaves are darker green and broader than those of birdsfoot trefoil. Inflorescences are umbel-like cymes with 8-14 florets per flower head (fewer, 4-8 in birdsfoot trefoil, L. corniculatus). The calyx is a dentate tube and the yellow five-petalled corolla is often tinged with red. The plant is is outcrossing and pollination is mainly by honey bees. The seed pods which contain about 20 seeds, change colour from green to brown as they ripen. The seeds are round or spherical, much smaller than birdsfoot trefoil seed, and coloured from greenish yellow to dark brown. The plant is tap-rooted but later root growth is by rhizomes, initiated from the basal crown; seasonal regrowth and adventitious roots are initiated from rhizomes. Distribution. Primary distribution in western Europe and mediterranean coast of north Africa; secondarily in New Zealand, coastal south-east Australia, and to a lesser extent in north-west USA and South America. Characteristics. Perennial with mainly procumbent growth habit. Adapted to wetter conditions than birdsfoot trefoil but less winter hardy and less drought resistant. Has weak seedling emergence and slow establishment. Intermittent flowering and seed set during the season. Season of growth. Spring to autumn but peak growth in summer. Frost tolerance and regrowth. Tolerant of low winter temperatures though less than birdsfoot trefoil; regrowth slower than white clover. Temperature. Optimal temperature for summer growth circa 240C. Germination rate and percentage of tetraploid greater lotus is reduced by low temperature (50C) and fluctuating temperatures (5/l00C) compared with several other common legume species (Hampton et al., l987). Light. Long-day plant which needs a daylength of over l6 hours for profuse flowering. Has a degree of shade tolerance and is sown as ground cover in pine (Pinus radiata) plantations in New Zealand (Gadgil, et al., l986). Drought tolerance. Low; less than birdsfoot trefoil. Tolerance of flooding. Tolerates periods of waterlogging better than most forage legumes on account of root suberisation, the production of adventitious roots, the thickening of submerged stems and the transpiration of higher quantities of water (Shiferaw et al., l992). Soil requirements. Adapted to wet, acidic soils and low soil fertility, but its agronomic performance responds favourably to improved soil pH and fertility. Application of P and K to infertile soils benefits yield. In very acid soils has a high tolerance to Al (Wheeler et al., l992) and to Mn (Wheeler and Dodd, l995). Rhizobial relationships. Rhizobial inoculation of seed by effective, specific Rhizobium is needed when sowing, especially on land where it has not been grown before. It requires a different strain of Rhizobium from birdsfoot trefoil; higher rates of N-fixation under acid conditions were recorded from slow-growing Bradyrhizobium strains than faster-growing strains of Rhizobium lotii (Vance et al., l987). Ability to spread naturally. The main perennating organs are rhizomes which allow the plant to spread and develop in a similar way to white clover. Spread also assisted by natural reseeding and build-up of seed banks. In south-east Australia, the seed bank was positively associated with latitude, latitudes of over 320S being needed and negatively associated with monthly maximum temperatures in summer (Blumenthal and Harris, l993). Land preparation for sowing. well cultivated, uniform seed bed is required for best results since the very small seeds require shallow sowing. Sowing methods. The seed are normally broadcast or drilled after conventional cultivations. Seed can also be oversown into existing grassland following stock trampling pre-sowing to create bare soil spaces and then trampling again post-sowing to encourage soil-seed contact. Sowing depth and cover. The optimum depth is l0-l5 mm with a light but firm soil cover. Sowing time and rate. Best sown in spring unless the climate is warm temperate, when it can be sown in spring or autumn. If sown in autumn in cold temperate climes, diploid cultivars are sown at l-3 kg/ha and tetraploids at l-5 kg/ha, the higher rates being used for difficult conditions or when surface-seeded (Charlton, l992). Number of seeds per kg. Circa 2 000 000 for diploids and 1 250 000 for tetraploids. Percentage hard seeds. May reach 50% or more but germination of hard seeds can be high (Hampton et al., l987). Seed treatment before sowing. Scarification or soaking the seeds in a gypsum solution reduces the percentage hard seed. Commercial seed scarifiers are available (Hare and Rolston, l985). Nutrient requirements. Although adapted to low soil fertility, improvement of fertility by P and K application, and lime as required to raise soil pH, enhance yield. Compatibility with grasses and other legumes. Compatible with non-aggressive grasses such as timothy (Phleum pratense) or meadow fescue (Festuca pratensis). Can co-exist with white clover in warm temperate pastures, e.g. in southern Australia, but white clover is too competitive in cool temperate conditions. Ability to compete with weeds. Because of slow establishment ability, greater lotus does not compete well with broad-leaved weeds or aggressive volunteer grass weeds. Once established, becomes competitive unless overgrazed. Tolerance of herbicides. Tolerates the so-called ‘clover-safe’ herbicides, e.g. MCPB, 2,4-DB, benazolin types, but not the less-selective herbicides. Seedling vigour. Poor seeding vigour and therefore a clean seed bed is essential for good establishment. Vigour of growth and growth rhythm. Once established, is capable of vigorous growth when well fertilized. Grows slowly during early spring and peaks in summer. Nitrogen-fixing ability. Information scarce. On deep peat, fertilized with lime and P, N2-fixation was 35 kg/ha from a grass/greater lotus stand where the legume was 22% of the total yield (Laidlaw, l98l). Amounts of 40 to 60 kg/ha cited from improved upland pasture in Scotland (Wedderburn, l980). Response to defoliation. More tolerant of intensive grazing than birdsfoot trefoil. However, lax grazing is needed in late summer and autumn in order to encourage rhizome growth and spread, and hence aid stand persistence (Sheath, l980a, b). Grazing management. Some form of rotational grazing, lax rather than severe, favours plant persistence and yield. This is particularly important in late summer-early autumn to allow the spread of rhizomes (Wedderburn and Lowther, l985). Breeding system. Diploids have 2n=2x=12 chromosomes and tetraploids, 2n=4x=24. Plants are self-fertile and pollinated mainly by honey bees. Breeding objectives. Improvement in seedling vigour, competitiveness when sown in association with grass, regrowth following defoliation, drought resistance, yield and seed production. Dry matter yield. Yields vary depending upon growing conditions. Experimentally, yields between ll and l2 t DM/ha have been obtained. Suitability for hay and silage. Is a suitable species for conservation as hay or silage. Feeding value. Largely determined by stage of growth at time of utilization since feeding value falls with increasing maturity and associated stemminess. In the northern tablelands of eastern Australia the N content and in vitro dry matter digestibility (DMD) of the winter growth declined by 20-25% in comparison with no decline for white clover (Schiller and Ayers, l993). The presence of condensed tannins in the forage prevents bloating in ruminants and is nutritionally advantageous since thetannins protect plant proteins in the rumen from degradation to ammonium, thus allowing more protein to be utilized in the small intestine (Waghorn et al., l987). Voluntary intake and rumen digestion are adversely affected if there is a high concentration of condensed tannins in the forage fed (Barry and Duncan, l984). Acceptability. Highly acceptable whether at vegetative stage for grazing, or as conserved hay or silage. Seed harvesting methods. Seed production is concentrated in New Zealand. Low plant density, 20-30 plants/m2, encourages seed yields (Hare l984) and in older crops, chemicals, e.g. atrazine may be used to thin stands and encourage better inflorescence development and seed yields (Hare l987; Hare l992). Row cropping allows good weed control and crop management generally. The chemical growth regulator, cyclocel, increases seed yield by increasing the number of pods and seeds per pod (Tabora and Hill, l992). Cutting or grazing the crop before closing stands for seed cropping should be lax, leaving a stubble of l0 cm or so. Cutting and swathing the crop to dry it slowly, or the use of chemical desiccation before cutting, minimises pod shatter and loss of seeds. Seed yields. Average yields of 400 kg/ha for diploid cv. Grasslands Sunrise and 250 kg/ha for cv. Grasslands Maku are harvested in New Zealand. (Hare and Lucas, 1984). Seed quality standards. Certified seed require a minimum germination of 75%, and a maximum permissible hard seed content of 40%, both percentages by number of pure seeds in the sample. The required analytical purity is 95% by weight. The maximum permissible content of seeds of other species is l.8% by weight. Cultivars. Limited range of cultivars. Australasian examples are the diploids Grassland Sunrise and Sharna, and the tetraploid Grasslands Maku. American examples are the diploids Marshfield and Kaiser. Diseases. Information is sparse. Pests. In New Zealand, greater lotus is resistant to the grass grub (Costelybra Zealandica). A range of pests e.g. mirids (Calocoris norvegicus) can affect seed crops but effective insecticides are available. Main attributes. A pioneer, perennial legume adapted to wet, acid, infertile soil conditions but responds to improved fertility. Natural reseeding and spread by rhizomes aid its persistence. Tolerant of flooding. Highly acceptable forage. Does not cause bloat in cattle because of presence of of condensed tannins. Main shortcomings. Not a forage legume for high-fertility soils where it is outperformed by other major forage legumes. Has a slow germination and slow seedling growth. Limited range of cultivars. Difficult to obtain consistent, high yields of seeds. Performance. Excellent individual lamb performance reported (Ulyatt, l98l; Purchas and Keogh, l984). Links:
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