The role of time of emergence in determining the growth of individual plants in swards of subterranean clover (Trifolium subterraneum L.)

1963 ◽  
Vol 14 (5) ◽  
pp. 628 ◽  
Author(s):  
JN Black ◽  
GN Wilkinson
Keyword(s):  
Growth Rate ◽  
Agricultural Research ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Competitive Environment ◽  
Subsequent Growth ◽  
Competitive Effects ◽  
Emergence Patterns ◽  
Final Yield

An experiment was carried out which enabled a separate assessment to be made of the influence of, firstly, pre-emergence growth rate, and secondly, the competitive environment at emergence on the subsequent growth of individual plants of subterranean clover. Swards of the Bacchus Marsh variety were grown in large seed boxes at the Waite Agricultural Research Institute, Adelaide. Four different sowing treatments were applied whereby the sowing of alternate plants in a checkerboard grid was delayed by 0, 2, 4, and 8 days. Emergence date and final dry weight were recorded individually for each plant in the experimental swards. There was considerable overlap in emergence times between the earlier and the later-sown plants. Consequently by a comparison of the separate regressions for earlier and later-sown plants of yield per plant on day of emergence for each treatment, it could be demonstrated that plants with very different pre-emergence growth rates but emerging on the same day in the same sward, and hence into the same competitive environment, gave essentially the same subsequent growth. In other words, in the absence of differential competitive effects, there was no detectable influence of pre-emergence growth rate on subsequent growth. On the other hand, the final dry weights of individual plants were very strongly related to day of emergence. A delay in emergence of 5 days brought about a reduction in final yield of about 50%, and a delay of 8 or 9 days of at least 75%. In view of the negligible influence of pre-emergence growth rate, per se, this reduction is attributable solely to the increased severity of competition from plants already emerged. In spite of the wide variation in emergence patterns, the total yields of all swards were very similar, indicating an almost complete compensation between plants in the utilization of available growth factors.

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.

scholarly journals The Interaction of Light and Temperature in Determining the Growth Rate of Subterranean Clover (Trifolium Subterraneum l.)

1955 ◽  
Vol 8 (3) ◽  
pp. 330 ◽  
Author(s):  
JN Black
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Agricultural Research ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Vegetative Stage ◽  
Agricultural Research Institute ◽  
Waite Agricultural Research Institute ◽  
Pot Culture

An experiment is described in which the growth of subterranean clover (Trifolium subterraneum L.) in the early vegetative stage was measured over 52 consecutive weekly periods. To eliminate possible trends of growth rates with age, plants of comparable morphological stage were used for each period. The variety Bacchus Marsh was grown in pot culture in the open at the Waite Agricultural Research Institute, Adelaide, South Australia.

The early vegetative growth of three strains of subterranean clover (Trifolium subterraneum L.) in relation to size of seed

1957 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
JN Black
Keyword(s):  
Size Distribution ◽  
Agricultural Research ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Leaf Production ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Waite Agricultural Research Institute ◽  
Early Production

Three strains of subterranean clover (Bacchus Marsh, Clare, and Mount Barker) were grown in pot culture at the Waite Agricultural Research Institute; for each strain, seed of four widely separated sizes mere sown. Dry weight a t any one time in the early vegetative stage was linearly related to embryo weight, but was independent of strain. Hence differences in early growth noted under uniform environmental conditions between strains are the result not of differing relative growth rates, but of differences in the size distribution within the seed populations; evidence is presented suggesting that there may well be little difference in the size distribution of seed of Bacchus Marsh and Mt. Barker, but that Clare contains a higher proportion of large seed, and thus as a strain would be expected to give greater early production. Leaf area per plant was also linearly related to embryo weight but independent of strain; but for a common embryo weight, Clare was found to have fewer leaves than the other two strains. Examination of the areas of successive leaves showed that the maintenance of similar total leaf areas depended on a balance of rate of leaf production and size of individual leaves; in relation to Bacchus Marsh and Mt. Barker, Clare has fewer but large1 leaves.

The influence of temperature and density on the growth of communities of subterranean clover (Trifolium subterraneum L. cv. Mount Barker)

1973 ◽  
Vol 24 (4) ◽  
pp. 479 ◽  
Author(s):  
PS Cocks
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Plant Size ◽  
Area Index ◽  
Influence Of Temperature ◽  
Total Dry Weight ◽  
Increasing Temperature

The influence of temperature on the growth of high and low density communities of subterranean clover (Trifolium subterraneum L. cv. Mount Barker) was studied at four temperatures ranging from 12�C day/7�C night to 27�C day/22�C night. The response to temperature depended on leaf area index (LAI). When the LAI was low (0.2), growth rate increased with increasing temperature to a maximum at 22� day/ 17�C night. This agreed with the temperature response of single plants of the same species previously reported. However, when the LAI was 3 the growth rate was not influenced by temperature within the range tested. At a still higher value of LAI (5.5), the response in growth became negative with increasing temperature, communities at the highest temperature growing at only half the rate of those at the lowest. The frequency distribution of plant size in the dense communities was measured, at eight times during the experiment. The distribution was influenced by both temperature and the total dry weight of the community. At low temperature it was approximately symmetrical, but at high temperature it rapidly became asymmetric as total dry weight increased, the amount of skewness being greatest at the highest temperature and dry weight. Plant death was greatest at the high temperature. The communities were divided into five equally populated groups of ascending plant size. At high temperature the largest plants increased in size throughout the experiment, but each of the groups of smaller plants reached a maximum size, subsequently losing weight. At lower temperatures only the groups of smaller size lost weight, the number of groups losing weight depending on temperature. The distribution data were used to try to explain the interaction between temperature and LAI. It was proposed that community growth rate was best when canopy cover was complete and the distribution of plant weight was not strongly skewed.

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.

The significance of petiole length, leaf area, and light interception in competition between strains of subterrranean clover (Trifolium subterraneum L.) grown in swards

1960 ◽  
Vol 11 (3) ◽  
pp. 277 ◽  
Author(s):  
JN Black
Keyword(s):  
Leaf Area ◽  
Leaf Development ◽  
Plant Competition ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Sampling Period ◽  
Dry Weight ◽  
Petiole Length ◽  
Petiole Elongation ◽  
Light Profiles

Three strains of subterranean clover differing in leaf development were grown in pure swards and in all combinations in mixtures. The strain Yarloop has relatively few large leaves held on long petioles; Tallarook has many small leaves and short petioles; Bacchus Marsh is intermediate in all these respects. The swards were grown in boxes and were sampled on four occasions during the period of vegetative growth. Leaf area in each 2 cm layer of the sward was determined separately, and for both strains in the mixed swards, and measurements of the light intensity reaching each layer were obtained. Root weights were determined for all swards and separately for each component of the mixed swards. Examination of the dry weights showed that the growth of the strain having the lesser petiole elongation was suppressed. In the extreme instance Tallarook was so suppressed when grown with Yarloop that in the final inter-sampling period it grew completely in the dark, and lost about half its dry weight. Bacchus Marsh also suppressed Tallarook, but to a lesser extent, while Bacchus Marsh was itself suppressed in competition with Yarloop. The amount of light energy intercepted by the two components of the mixed swards was calculated from the leaf area and light profiles, and confirmed the importance of the spatial distribution of leaves in plant competition. It was concluded that, in the absence of defoliation, the success of a strain under competition was associated with its potential petiole elongation.

Subterranean clover mottle virus infection of subterranean clover: widespread occurrence in pastures and effects on productivity

1992 ◽  
Vol 43 (7) ◽  
pp. 1597 ◽  
Author(s):  
JM Wroth ◽  
RAC Jones
Keyword(s):  
Systemic Infection ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Seed Transmission ◽  
Dry Weight ◽  
Widespread Occurrence ◽  
Transmission Rates ◽  
Type Isolate ◽  
Growing Seasons ◽  
South West

In 1989 and 1990, infection with subterranean clover mottle sobemovirus (SCMV) was widespread in subterranean clover ( Trifolium subterraneum L.) pastures in the south-west of Western Australia. The virus was detected in 61% of the pastures sampled and incidences of infection ranged from 1 to 50%. The virus was more common in old pastures than in pastures resown with newer cultivars during the preceeding 5 year period. When 12 isolates of SCMV were inoculated to subterranean clover plants grown in the glasshouse, symptoms varied from mild to severe. SCMV isolates P23 and F4 decreased the herbage dry weight of cw. Daliak and Woogenellup grown in plots as spaced plants by 81-88% while the Type isolate caused losses of 92%. By contrast, losses were 37-49% with cv. Karridale, a cultivar in which systemic infection was either delayed or prevented during winter. Infection decreased seed yield by c. 90% in cvv. Karridale and Woogenellup with all three isolates; seed weight was decreased 21-55%. A small proportion of cv. Woogenellup transplants outgrew the infection in new shoots during late spring to produce abundant healthy foliage. SCMV seed transmission rates in seed collected from infected transplants of cv. Woogenellup were 0.06, 0.07 and 0.43% for the Type, P23 and F4 isolates respectively. It was concluded that SCMV was present in most pastures, but at low incidences, and that it persists in them from year to year. Extended growing seasons and hard grazing are likely to increase its incidence.

Copper nutrition of subterranean clover (Trifolium subterraneum L. cv. Seaton Park). I. Effects of copper supply on growth and development

1981 ◽  
Vol 32 (2) ◽  
pp. 257 ◽  
Author(s):  
DJ Reuter ◽  
AD Robson ◽  
JF Loneragan ◽  
DJ Tranthim-Fryer
Keyword(s):  
Root Growth ◽  
Growth And Development ◽  
Copper Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Growing Season ◽  
Internode Elongation ◽  
Plant Parts ◽  
Lateral Branches

Effects of severe and moderate copper deficiency on the development of leaves and lateral branches, on the distribution of dry weight within the plant, and on seed yield of Seaton Park subterranean clover were assessed as part of three glasshouse experiments. Copper deficiency markedly depressed top and root growth without producing any distinctive symptoms. It retarded phasic development by delaying development of leaves and lateral branches, senescence of plant parts, and flowering: it also depressed the proportion of stem plus petiole in plant tops and decreased internode elongation, pollen fertility and the number of burrs and seeds formed. As a result of its effect in delaying flowering, copper deficiency would depress seed production particularly strongly when low soil water supply shortens the growing season. The need for suitable procedures for diagnosing copper deficiency is emphasized by the lack of specific plant symptoms in this species.

Effect of management system and stocking rate on the performance of ewes and lambs

1976 ◽  
Vol 16 (83) ◽  
pp. 810 ◽  
Author(s):  
BD Hill ◽  
DG Saville
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Management System ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Body ◽  
Stocking Rate ◽  
Wool Production ◽  
South Wales ◽  
Lamb Growth

A grazing experiment was conducted at Cowra, on the western slopes of New South Wales, on a pasture consisting of lucerne (Medicago sativa) and annual species including capeweed (Arctotheca calendula), barley grass (Hordeum leporinum). wimmera ryegrass (Lolium rigidum) and subterranean clover (Trifolium subterraneum) . The performance of Border Leicesterx Merino ewes mated to Dorset Horn rams and the growth of their progeny was compared under rotational and set stocked grazing management systems, with and without a 20 per cent area of lucerne saved for grazing when additional feed was required. There was one stocking rate (8.7 ewes ha-1) in 1966 and two (8.7 ewes ha-1 and 13.0 ewes ha-1) in 1967 to 1969. Rotational grazing decreased the lamb growth rate but increased the number of lambs born. The management system did not affect the body weight or wool production of the ewes. Lucerne was quickly eliminated from the set stocked areas and was greatly reduced in the rotational systems. Capeweed became dominant in the set stocked areas. Saving increased the number of lambs born at the high stocking rate in 1967 to 1969. In 1966 saving reduced lamb growth, ewe body weight and wool growth in the rotational system. The high stocking rate increased wool production per hectare, but decreased the number of lambs born and, in 1967, the lamb growth rate.

Zinc in subterranean clover (Trifolium subterraneum L. cv. Seaton Park). I. Effects of zinc supply on distribution of zinc and dry weight among plant parts

1982 ◽  
Vol 33 (6) ◽  
pp. 989 ◽  
Author(s):  
DJ Reuter ◽  
JF Loneragan ◽  
AD Robson ◽  
D Plaskett
Keyword(s):  
Zinc Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Physiological Age ◽  
Vegetative Development ◽  
Plant Parts ◽  
Zinc Concentrations ◽  
Complex Relationships ◽  
Lateral Branches

Effects of zinc supply on the distribution of zinc and dry weight among plant parts were examined during the first 55 days of vegetative development of Seaton Park subterranean clover grown in a zinc-deficient soil in a glasshouse. Symptoms of zinc deficiency first appeared in young trifoliate leaves. Zinc deficiency decreased the expansion of blades and petioles, delayed the development of leaves and lateral branches, depressed dry weights of roots and shoots, and increased the proportion of plant dry weight in roots and leaf blades. In each treatment and at each harvest, zinc concentrations varied widely amongst plant parts and with their physiological age. Plant parts also differed widely in the response of their dry matter and zinc concentrations to both zinc treatment and harvest time. It is suggested that these complex relationships explain why plant samples consisting of composite plant parts are not suitable for diagnosis of zinc deficiency. In the present experiment, zinc concentration in whole shoots was unsatisfactory for diagnosing zinc deficiency since concentrations were higher in young, zinc-deficient plants than in older, zinc-adequate plants. In young leaf blades of the same physiological age, zinc concentrations showed reasonably constant relationships with plant growth throughout the entire experiment. However, they varied two- to three-fold in leaves of different ages from the same plants. The results show the importance for diagnosis of zinc deficiency of selecting as a sample a single organ of defined physiological age. The youngest open leaf blade is recommended for diagnosis of zinc deficiency in subterranean clover.

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