Border and orientation effects and their elimination in experimental swards of subterranean clover (Trifolium subterraneum L.)

1961 ◽  
Vol 12 (2) ◽  
pp. 203 ◽  
Author(s):  
JN Black
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Light Energy ◽  
Border Effect ◽  
Orientation Effects

Two experiments were carried out in swards of subterranean clover, of the variety Bacchus Marsh, to determine the width of the border required firstly at the edge of swards and secondly between harvest areas. Peripheral growth was restricted by (a) root panels, (b) leaf panels, and (c) root and leaf panels; a fourth treatment with no lateral restrictions was also used. The results showed that in a sward growing without restrictions, a border at the edge of only 2 in. was required before homogeneous dry weights were reached. This border effect could be eliminated by using leaf- or leaf- and root-restricting panels, but not by root panels alone. The data for borders between harvest areas were more difficult to interpret, but growing swards without panels while allowing for a 3 in. border, both at the periphery and between defoliated areas, is recommended as the simplest procedure. From a consideration of marginal growth under the different peripheral restriction regimes it was concluded that water and nutrients were non-limiting, but that sward growth was limited by the amount of light energy intercepted.

Competition between two varieites of subterranean clover (Trifolium subterraneum L.) as related to the proportions of seed sown

1961 ◽  
Vol 12 (5) ◽  
pp. 810 ◽  
Author(s):  
JN Black
Keyword(s):  
Vegetative Growth ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Light Energy ◽  
Sampling Occasion ◽  
Large Seed ◽  
Light Intensities ◽  
Petiole Elongation

The Yarloop and Tallaroolr varieties of subterranean clover (Trifolium subterraneum L.) xvere grown in swards in six mixtures, varying from 100% Yarloop/0%, Tallarook to 0% Yarloop/100% Tallarook, to find out whether the suppression of Tallarook by Yarloop consequent upon the greater petiole elongation of yarloop would still occur when only a few Yarloop plants were present. The swards were grown in large seed boxes and were sampled on four occasions during vegetative growth. Leaf areas for each 2 cm layer of the swards were determined separately for the two strains, and light intensities at each layer were measured at each sampling occasion. It was shown that Yarloop plants suppressed Tallarook in all mixtures. The relative amounts of light energy available to the two strains in the mixed swards left no doubt that the suppression of Tallarook was the result of shading by the taller-growing Yarloop plants.

Defoliation as a factor in the growth of varieties of subterranean clover (Trifolium subterraneum L) when grown in pure and mixed swards

1963 ◽  
Vol 14 (2) ◽  
pp. 206 ◽  
Author(s):  
JN Black
Keyword(s):  
Agricultural Research ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Light Energy ◽  
Weight Changes ◽  
Agricultural Research Institute ◽  
Large Seed ◽  
Waite Agricultural Research Institute ◽  
High Yielding Varieties

This paper describes two experiments analysing the recovery from defoliation of subterranean clover varieties grown in swards in large seed boxes at the Waite Agricultural Research Institute, Adelaide. The first experiment examined the way in which the six common commercial varieties recovered from a single severe defoliation, and showed that under these conditions they can be placed in three groups: Yarloop and Clare are tall, high-yielding varieties with few, large leaves, recovering slowly from defoliation; Tallarook and Dwalganup are prostrate varieties, lower-yielding, with many small leaves, recovering rapidly after defoliation; Bacchus Marsh and Mount Barker are intermediate in all respects. In the second experiment mixed swards of equal numbers of Yarloop and Tallarook plants were grown under three treatments: A, no defoliation; B, defoliated twice at a height which removed the higher Yarloop canopy but left the lower Tallarook plants untouched; C, defoliated twice at a height which removed the canopies of both varieties. Measurement of dry weight on four occasions after each defoliation showed that in the undefoliated treatment, all Tallarook plants died by the end of the experiment. In the defoliated treatments, the removal of the Yarloop canopy resulted in only a temporary improvement in the illuniination in which the Tallarook plants grew, and their dry weight and plant numbers progressively declined. Dry weight changes in the Tallarook component were shown to be dependent on the light energy available to it, which was in turn determined by the light-absorbing capacity of the superior Yarloop canopy. In mixed swards, the ability of Yarloop to re-establish quickly a leaf canopy above that of Tallarook appeared to explain its success when defoliated.

Competition between plants of different initial seed sizes in swards of subterranean clover (Trifolium subterraneum L.) with particular reference to leaf area and the light microclimate

1958 ◽  
Vol 9 (3) ◽  
pp. 299 ◽  
Author(s):  
JN Black
Keyword(s):  
Leaf Area ◽  
Incident Light ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Light Energy ◽  
Light Extinction ◽  
Unexpected Finding ◽  
Sampling Occasion ◽  
Area Index ◽  
Initial Seed

A study was made of the development and fate of individual plants growing from contrasting seed sizes in swards of subterranean clover (var. Bacchus Marsh). Three sets of swards were grown in boxes, from large, small, and mixed (large and small) seeds respectively, all sown at the same number of plants per unit area; the swards were harvested on five occasions. Leaf area in each 2 cm layer of the sward was determined separately and measurements of the light intensity reaching each layer were obtained at each harvest. Counts of the plants on each occasion revealed a steady drop of about 30 per cent. over the whole period; in the "mixed" swards, only plants from small seed sizes died, the number of large-seeded plants remaining unchanged. The data of leaf area and numbers in each layer showed that leaf area is concentrated in a relatively shallow band at the top of the sward, the area attained by individual leaves increasing with height in the sward and with time. Leaves are not retained in the canopy at heights below that at which light extinction occurs. An unexpected finding was that, as the sward developed, the leaf area index (the ratio of leaf area to ground covered) required for the absorption of all incident light energy increases, and it is suggested that this is due to changes in leaf morphology. The importance of the position at which leaves of individual plants are held in the canopy is stressed; although at the first sampling occasion, the small-seeded plants had 25 per cent. of the leaf area of the mixed sward, they were so located as to absorb only 10 per cent. of the incident light energy; at the last sampling occasion, the values were 10 and 2 per cent. respectively. It is concluded that the disappearance of the small-seeded plants from the mixed swards was due to shading from the large-seeded plants.

Competition among seedlings of perennial grasses, subterranean clover, white clover, and annual ryegrass in replacement series mixtures

2000 ◽  
Vol 51 (3) ◽  
pp. 377 ◽  
Author(s):  
G. M. Lodge
Keyword(s):  
White Clover ◽  
Plant Competition ◽  
Perennial Grass ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Perennial Grasses ◽  
Maximum Likelihood Estimates ◽  
Annual Ryegrass ◽  
Replacement Series ◽  
Successful Establishment

Seedlings of 3 perennial grasses, Danthonia linkii Kunthcv. Bunderra, D. richardsonii Cashmore cv. Taranna(wallaby grasses), and Phalaris aquatica L. cv. Sirosa,were each grown in replacement series mixtures with seedlings ofTrifolium repens L. (white clover),Trifolium subterraneum L. var. brachycalycinum (Katzn.et Morley) Zorahy & Heller cv. Clare (subterraneanclover), and Lolium rigidum L. (annual ryegrass). Plantswere sown 5 cm apart in boxes (45 by 29 by 20 cm) at a density of 307plants/m2. Maximum likelihood estimates were usedto derive parameters of a non-linear competition model using the dry matterweights of perennial grasses and competitors at 3 harvests, approximately 168,216, and 271 days after sowing. Intra-plant competition was examined inmonocultures of each species, grown at plant spacings of 2, 5, and 8 cm apartwith plants harvested at the above times.Competition occurred in all perennial grass–competitor mixtures, exceptin those of each perennial grass with white clover and thephalaris–subterranean clover mixture (Harvest 1) and those withD. richardsonii and phalaris grown with white clover(Harvest 2). For D. richardsonii (Harvests 1 and 2) andD. linkii (Harvest 1 only) grown with white clover andthe phalaris–subterranean clover (Harvest 1), the two species in themixture were not competing. In the phalaris–white clover mixture, eachspecies was equally competitive (Harvests 1 and 2). These differences incompetition and aggressiveness reflected differences in individual plantweights in monocultures where there was an effect (P < 0.05) of species ondry matter weight per box, but no significant effect of plant spacing.These data indicated that for successful establishment,D. richardsonii and D. linkiishould not be sown in swards with either subterranean clover or white clover,or where populations of annual ryegrass seedlings are likely to be high.Phalaris was more compatible with both white clover and subterranean clover,but aggressively competed with by annual ryegrass.

scholarly journals Host plant recognition by the root feeding clover weevil, Sitona lepidus (Coleoptera: Curculionidae)

2004 ◽  
Vol 94 (5) ◽  
pp. 433-439 ◽  
Author(s):  
S.N. Johnson ◽  
P.J. Gregory ◽  
P.J. Murray ◽  
X Zhang ◽  
I.M. Young
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Plant Roots ◽  
Grass Species ◽  
Movement Rates ◽  
Sitona Lepidus ◽  
Macro Scale ◽  
Significant Difference ◽  
Invasive Techniques ◽  
Root Feeding

AbstractThis study investigated the ability of neonatal larvae of the root-feeding weevil, Sitona lepidus Gyllenhal, to locate white clover Trifolium repens L. (Fabaceae) roots growing in soil and to distinguish them from the roots of other species of clover and a co-occurring grass species. Choice experiments used a combination of invasive techniques and the novel technique of high resolution X-ray microtomography to non-invasively track larval movement in the soil towards plant roots. Burrowing distances towards roots of different plant species were also examined. Newly hatched S. lepidus recognized T. repens roots and moved preferentially towards them when given a choice of roots of subterranean clover, Trifolium subterraneum L. (Fabaceae), strawberry clover Trifolium fragiferum L. (Fabaceae), or perennial ryegrass Lolium perenneL. (Poaceae). Larvae recognized T. repens roots, whether released in groups of five or singly, when released 25 mm (meso-scale recognition) or 60 mm (macro-scale recognition) away from plant roots. There was no statistically significant difference in movement rates of larvae.

The influence of seed size and depth of sowing on pre-emergence and early vegetative growth of subterranean clover (Trifolium subterraneum L.)

1956 ◽  
Vol 7 (2) ◽  
pp. 98 ◽  
Author(s):  
JN Black
Keyword(s):  
Leaf Area ◽  
Seed Size ◽  
Vegetative Growth ◽  
Dry Matter ◽  
Relative Rate ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Total Leaf Area ◽  
Pot Culture

Changes in the pre-emergence distribution of dry matter in subterranean clover (Trifolium subterraneum L.) variety Bacchus Marsh were followed at 21°C, using three sizes of seed and three depths of sowing, ½, 1¼, and 2 in. Decreasing seed size and increasing depth of sowing both reduce the weight of the cotyledons a t emergence. Seed of the three sizes were sown a t three depths in pot culture a t staggered intervals so that emergence was simultaneous. Dry weight in the early vegetative stage was proportional to seed size, and total leaf area and leaf numbers showed similar trends. Plants of each seed size grew at the same relative rate. No effect of depth of sowing could be detected, and this was shown to be due to the cotyledon area a t emergence being constant for any given seed size, regardless of varying depth of sowing and hence of cotyledon weight. It was concluded that seed size in a plant having epigeal germination and without endosperm is of importance: firstly, in limiting the maximum hypocotyl elongation and hence depth of sowing, and secondly, in determining cotyledon area. Cotyledon area in turn influences seedling growth, which is not affected by cotyledon weight. Once emergence has taken place, cotyledonary reserves are of no further significance in the growth of the plants.

CANTERBURY EXPERIENCE WITH SUBTERRANEAN CLOVER (Trifolium subterraneum)

1935 ◽  
pp. 64-68
Author(s):  
H. Neave ◽  
C.H. Hewlett
Keyword(s):  
Personal Experience ◽  
Subterranean Clover ◽  
Trifolium Subterraneum

The information contained in this paper is principally first-hand knowledge extending over a period of six years gained from personal experience from our own "Oakleigh" farm.

Varietal reactions of Trifolium subterraneum L. to Phaseolus virus 2 Pierce.

1954 ◽  
Vol 5 (4) ◽  
pp. 598 ◽  
Author(s):  
EM Hutton ◽  
JW Peak
Keyword(s):  
Trypan Blue ◽  
Continuous Distribution ◽  
Systemic Infection ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Epidermal Cells ◽  
Severe Strain ◽  
Resistant Varieties ◽  
Lethal Reaction ◽  
The Mean

A number of varieties of subterranean clover (Trifolium subterraneum L.) were tested with a severe strain of Phaseolus virus 2 Pierce. Northam First Early, Dwalganup, and Pink Flowered gave lethal necrotic reactions while the rest developed mottles and chlorosis of different degrees of intensity. Reductions in the mean fresh weights of plants of five subterranean clover varieties ranged from 26.1 to 76.7 per cent. Epidermal cells of mottled leaves contained irregular aggregates of viroplasts stained by treatment with phloxine-trypan blue. Viroplasts in young tip leaves did not stain if the plants were held at temperatures below 44.6°F while those in mature basal leaves were not so affected. The lethal-reactors Northam First Early, Dwalganup, and Pink Flowered were resistant in the field to Phaseolus virus 2. With hand inoculation in the glass-house an average of 10 per cent. of plants of these varieties remained free from systemic infection, whereas all the plants of mottle-reacting varieties became systemically infected. The virus had a discontinous distribution in plants of lethal-reactors, compared with a continuous distribution in those of mottle-reactors such as Mount Barker. The lethal reaction is heritable in a dominant fashion in most crosses, so that the development of desirable new virus- resistant varieties is possible.

scholarly journals Harvesting subterranean clover seed – current practices, technology and issues

2021 ◽  
Vol 72 (3) ◽  
pp. 223
Author(s):  
Wesley M. Moss ◽  
Andrew L. Guzzomi ◽  
Kevin J. Foster ◽  
Megan H. Ryan ◽  
Phillip G. H. Nichols
Keyword(s):  
Soil Erosion ◽  
Case Studies ◽  
Seed Production ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Root Cause ◽  
Pasture Plant ◽  
Clover Seed ◽  
Production Industry ◽  
Pasture Legume

Subterranean clover (Trifolium subterraneum L.) is Australia’s most widely sown annual pasture legume. Its widespread use as a pasture plant requires a well-functioning seed production industry, and Australia is the only significant producer of subterranean clover seed globally. However, the sustainability of this industry is under threat due to its reliance on ageing harvest equipment and the resultant environmental impacts. In order to evaluate seed harvesting practices, technology, and issues, we report on case studies, workshops, and a survey of seed producers across southern Australia. The Horwood Bagshaw Clover Harvester, designed in the 1950s, remains the most popular subterranean clover seed harvester. We discuss its use and modifications, and document several contemporary issues facing the seed production industry. Issues are primarily soil erosion and degradation; the expensive, slow and labour-intensive harvest process; and poor reliability and maintainability of harvesters that are now at least 30 years old. We conclude the root cause of these issues is the suction harvest technology utilised by the Horwood Bagshaw Clover Harvester. Analysis of the current harvest system is provided to support the development of new approaches to harvest subterranean clover seeds.

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