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.

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.

scholarly journals Annual pasture legumes for farming systems in cool-temperate areas with summer soil moisture deficits

2003 ◽  
Vol 11 ◽  
pp. 149-154 ◽  
Author(s):  
P.M. Evans ◽  
X.Z. Zhang ◽  
P.A. Riffkin
Keyword(s):  
Crop Rotation ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Farming Systems ◽  
Seed Banks ◽  
Temperate Climate ◽  
Large Seed ◽  
Pasture Legumes ◽  
Rotation System ◽  
Cool Temperate

Seed softening rates of subterranean clover (Trifolium subterraneum) are lower in cool-temperate environments than in typical Mediterranean areas, allowing the accumulation of large seed banks. These large seed banks should enable a pasture to selfregenerate following a year of cropping in which the pasture has been removed. To test this hypothesis, a 1:1 pasture/crop rotation system was established at three sites in southern Victoria, Australia, with subterranean, balansa (T. michelianum), Persian (T. resupinatum) and arrowleaf (T. vesiculosum) clovers. At Hamilton, pure subterranean clover herbage yields of up to 10 t DM/ha were obtained under grazing. This was followed by wheat grain yields averaging 7 t/ha with 12.7% grain protein over three seasons. After a year of dryland cropping, the pastures selfregenerated with more than 3 000 clover seedlings/ m2. At Gnarwarre and Streatham, all four clover species were well adapted to the pasture/crop rotation in terms of their seed-seedling dynamics, with the highest regeneration after cropping at 8 000 seedlings/m2 in balansa clover and the highest seasonal herbage production of 12.8 t DM/ha in arrowleaf clover. No nitrogen fertiliser was applied in the system. Key words: annual legumes, cool-temperate climate, crops, seed softening rates

scholarly journals Influence of cover crop treatments on the performance of a vineyard in a humid region

2015 ◽  
Vol 13 (4) ◽  
pp. e0907 ◽  
Author(s):  
Emiliano Trigo-Córdoba ◽  
Yolanda Bouzas-Cid ◽  
Ignacio Orriols-Fernández ◽  
Emilia Díaz-Losada ◽  
Jose M. Mirás-Avalos
Keyword(s):  
Cover Crops ◽  
Vegetative Growth ◽  
Cover Crop ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Soil Tillage ◽  
Native Vegetation ◽  
Stem Water Potential ◽  
Berry Quality ◽  
Berry Composition

Vineyards are usually managed by tilling the inter-rows to avoid competition from other plants for soil water and nutrients. However, in humid and sub-humid climates, such as that of NW Spain, cover crops may be an advantage for controlling vine vegetative growth and improving berry composition, while reducing management costs. The current study was conducted over three consecutive growing seasons (2012-2014) to assess the effects of establishing three permanent cover crop treatments on water relations, vine physiology, yield and berry composition of a vineyard of the red cultivar ‘Mencía’ (<em>Vitis vinifera </em>L.) located in Leiro, Ourense. Treatments consisted of four different soil management systems: ST, soil tillage; NV, native vegetation; ER, English ryegrass (<em>Lolium perenne</em> L.); and SC, subterranean clover (<em>Trifolium subterraneum</em> L.). Midday stem water potential was more negative in the native vegetation treatment, causing significant reductions in leaf stomatal conductance on certain dates. Total vine leaf area and pruning weight was reduced in the cover crop treatments in the last year of the experiment. Yield was unaffected by the presence of a cover crop. No significant differences among treatments were observed for berry composition; however, wines were positively affected by the SC treatment (higher tannin content and colour intensity and lower malic acid concentration when compared with ST). Wines from the cover crop treatments were preferred by taste panelists. These results indicate that in humid climates cover crop treatments can be useful for reducing vine vegetative growth without compromising yield and berry quality.

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.

Translocation of Manganese in Subterranean Clover (Trifolium subterraneum L. Cv. Seaton Park) I. Redistribution During Vegetative Growth

1984 ◽  
Vol 11 (2) ◽  
pp. 101 ◽  
Author(s):  
RO Nable ◽  
JF Loneragan
Keyword(s):  
Vegetative Growth ◽  
Manganese Content ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Manganese Deficiency ◽  
No Net Loss ◽  
Deficiency Symptoms ◽  
Mature Leaves ◽  
Young Leaves ◽  
Nutrient Solutions

The mobility of manganese from old leaves and cotyledons during vegetative growth has been examined by following manganese content and radioactive manganese redistribution in parts of subterranean clover plants grown into manganese deficiency. In plants transferred from nutrient solutions with 1 �M Mn2+ to solutions without Mn2+, the amount of manganese in the roots decreased markedly. During the same period there was no net loss of manganese from cotyledons and old leaves, although plants developed severe manganese deficiency symptoms in young leaves. Old leaves of plants given an early supply of 54Mn lost no 54Mn when the plants were transferred to non-radioactive solutions without manganese for 14 days. Silicon, which is known to influence the distribution of manganese within leaves of some plants, had no effect on the loss of total manganese or 54Mn from old leaves. Detached green, mature leaves lost 40% of their manganese within 24 h when aerated in water. If leaching by rain removes substantial amounts of manganese from leaves of plants grown in the field, this may account for reports of manganese mobility in plant phloem. The present results establish that manganese is not mobile in the phloem of subterranean clover plants during vegetative growth.

Soil management for irrigated vegetable production. II. Possible causes for slow vegetative growth of lettuce associated with zero tillage

1993 ◽  
Vol 44 (4) ◽  
pp. 831 ◽  
Author(s):  
RJ Stirzaker ◽  
JB Passioura ◽  
BG Sutton ◽  
N Collis-George
Keyword(s):  
Vegetative Growth ◽  
Sandy Loam ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Vegetable Production ◽  
Zero Tillage ◽  
Evaporative Demand ◽  
Loam Soil ◽  
Hard Soil ◽  
Tillage Treatment

This work explores the consequences of using zero-tillage for irrigated vegetable production. The research is based on the hypothesis that, under the well-watered and adequately fertilized conditions prevailing in commercial vegetable growing, the reduced root density expected under zero-tillage should not limit vegetative growth. To test this hypothesis, irrigated lettuce crops were grown under a range of soil physical conditions on a hardsetting sandy loam soil. Crops were grown during the spring, autumn and summer, in order to compare zero-tillage and cultivation treatments under conditions of low, medium and high evaporative demand. Lettuce yields under zero-tillage were reduced relative to those under cultivation for each of these crops. However, calculations based on a model which describes the movement of water to roots show that the root length measured in the zero-tillage treatment greatly exceeded that required to meet the potential evaporative demand in the field. A possible explanation for the reduced growth is given, based on an inhibitory root signal which has been shown under controlled conditions to reduce shoot growth in hard soil even when the leaves are well supplied with water and nutrients. When lettuce was grown under zero-tillage, but following a crop of subterranean clover (Trifolium subterraneum L.) which senesced in summer to form an in-situ mulch, yield was as high as in cultivated soil. The soil near the surface in this treatment was not only moister and physically weaker than that from the conventional zero-tillage treatment, but also likely to contain biopores which would provide zones of low root impedance in an otherwise hard soil.

scholarly journals The Effect of Light on Zinc Deficiency in Subterranean Clover (Trifolium Subterraneum L.)

1955 ◽  
Vol 8 (3) ◽  
pp. 344 ◽  
Author(s):  
PG Ozanne
Keyword(s):  
Zinc Deficiency ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Weight ◽  
Daily Maximum ◽  
Light Intensities ◽  
The Mean ◽  
Zinc Response ◽  
The Difference ◽  
Effect Of Light

The effects of light on zinc response were investigated by growing subtermnean clover under daylight of various intensities. Plants were grown in limed Muchea sand and the zinc response was measured as the difference in dry weight between plants with and without added zinc. The light intensities are given as the mean daily maximum intensities.

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