The promotion of winter growth in pastures through growth substances and photoperiod

1967 ◽  
Vol 18 (2) ◽  
pp. 245 ◽  
Author(s):  
GW Arnold ◽  
D Bennett ◽  
CN Williams
Keyword(s):  
Growth Rate ◽  
Gibberellic Acid ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Normal Growth ◽  
Floral Initiation ◽  
Growth Substances ◽  
Time Of Application ◽  
Annual Grasses ◽  
Grazing Systems

The effects of growth substances and extended photoperiod on the growth rate of phalaris-annual grasses-subterranean clover pastures were studied at Canberra in the winter of 1964. Responses to applications of 4 and 20 g gibberellic acid (GA) per acre differed for June and July applications. All available data on GA responses on this pasture type were collated. Responses to GA increased with decreased growth rate of normal pasture. Thus a sixfold increase in growth rate was obtained when the normal growth rate was 2 lb dry matter/acre/day. Responses were independent of dose rate (from 1 to 105 g GA per acre) or time of application. Responses to GA were obtained subsequent to the first harvest. The length of time during which cumulative growth on GA-treated pastures exceeded that on normal pastures was related to the growth rate of the normal pastures. The response in growth to 4 g GA could be increased to the level of that obtained with 20 g GA by the addition of either 4 g naphthylacetic acid or 4 g kinetin. Phalaris showed greater response to GA than did annual grasses or subterranean clover. Extending the photoperiod to 16 hr gave a 40% increase in growth rate in winter. This was associated with earlier floral initiation whereas increases in growth rate induced by growth substances were not. These results are discussed in relation to increasing plant and animal productivity in year-round grazing systems.

Gibberellic acid and the growth of crop plants

1958 ◽  
Vol 50 (1) ◽  
pp. 49-59 ◽  
Author(s):  
D. G. Morgan ◽  
G. C. Mees
Keyword(s):  
Growth Rate ◽  
Gibberellic Acid ◽  
Crude Protein ◽  
Dry Matter ◽  
Field Trials ◽  
Natural Growth ◽  
Nitrogenous Fertilizer ◽  
Sodium Calcium ◽  
Normal Green ◽  
Stimulation Of

1. Field trials with gibberellic acid on grass, wheat, potatoes, turnips, carrots, peas, runner beans, lettuce, celery, blackcurrants, kale and maize are described. The effects on plant growth and crop yield were determined.2. The experiments on grassland were carried out between July 1953 and June 1956, and included trials at four different centres. They all gave essentially similar results.3. 2 oz. per acre of gibberellic acid sprayed at 100 gal. per acre stimulated the growth of all components of the swards. The stimulation was most clearly seen in spring and autumn when the natural growth rate was slow. At these times gibberellic acid was able to produce a grazeable growth of grass more rapidly than nitrogenous fertilizers. The stimulation of growth was accompanied by yellowing of the grass, but recovery to a normal green colour was speeded up by applying a nitrogenous fertilizer at the same time as the gibberellic acid spray.4. The dry-matter yields at the first cut following a treatment with gibberellic acid were increased by 0·6–10·8 cwt. per acre. The crude protein yields were also increased by the treatment, but to a relatively smaller degree, and the protein content of the grass was reduced by between ½ and 2%. The contents of phosphorus, potassium, sodium, calcium, barium, magnesium, manganese, copper, aluminium and tin were not altered.

The effect of time of application of superphosphate on seasonal yield of dry matter from annual pasture

1972 ◽  
Vol 12 (57) ◽  
pp. 392 ◽  
Author(s):  
AA McGowan ◽  
IH Cameron
Keyword(s):  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Matter Yield ◽  
Annual Grass ◽  
Time Of Application ◽  
Phosphorus Requirement ◽  
June July

The effect of time of application of superphosphate on the dry matter produced from a subterranean clover (Trifolium subterraneum)annual grass pasture was studied. Treatments involved an annual topdressing of superphosphate, at 125 kg ha-1, in a particular month of the year, for each of the twelve months ; there was also an unfertilized control. In winter, dry matter yield was increased by 350-1190 kg ha-1 when superphosphate was applied at any time of the year. Winter yields were higher after application in January to May (mean 1570 kg ha-1) than in October to December (mean 1190 kg ha-1) or in June-July (mean 1230 kg ha-1). In spring, the greatest increases in dry matter yield were from topdressing in August or September (1600 and 1210 kg ha-1 respectively). Spring yields following application in other months were smaller but usually significantly greater than the yield of unfertilized pasture. The response to autumn application of superphosphate was much greater in winter than in spring. This was not due to a lower phosphorus requirement by the pasture in spring than in winter.

scholarly journals (64) Effect of Plug Flats on Posttransplant Growth and Prevention of Stunting

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1012C-1012
Author(s):  
Aliya Donnell ◽  
John Dole
Keyword(s):  
Growth Rate ◽  
Gibberellic Acid ◽  
Plant Height ◽  
Light Quality ◽  
Growth Form ◽  
Normal Growth ◽  
Optimal Time ◽  
Nitrogen Enrichment ◽  
Cut Flower ◽  
Bedding Plant

Plug production is an integral part of today's floriculture industry. However, if seedlings are held in plug flats for too long, they may not return to a normal growth rate after transplanting. Stunting may render plants unsuitable for sale. Common bedding plant and cut flower species were grown in 288-plug flats to determine how long plugs could be held in the flats and still regain a normal growth rate and desirable growth form after transplanting. Species surveyed included: Antirrhinum, Begonia, Brassica, Callistephus, Celosia, Consolida, Dianthus, Eustoma, Gazania, Helianthus, Impatiens, Lycopersicon, Matthiola, Tagetes, and Viola. Ten randomly selected plugs were transplanted to 15- or 17-cm pots every 1 or 2 weeks for 10 weeks, when root balls were sufficiently developed to hold together after removal from the flat. Overall plant height was recorded for all species every 1 or 2 weeks. Plant diameter was recorded every 2 weeks for Begonia, Celosia, Eustoma, Helianthus, Impatiens, Lycopersicon, and Tagetes. A plug was considered to be stunted if it died after transplanting or did not resume a normal growth rate. Species that exhibited stunting included Brassica, Callistephus, Celosia, Consolida, Dianthus, and Tagetes. For example, Consolida seedlings held in the plug flat for 7 weeks after optimal transplanting time were six times smaller than those that were transplanted at the optimal time. Several factors were investigated to determine how they affected the degree of stunting, including: light quality, root obstruction, nitrogen enrichment prior to transplanting, gibberellic acid addition prior to transplanting, teasing of the root ball prior to transplanting, and length of drainage column.

A growth model for Trifolium subterraneum L. Swards

1978 ◽  
Vol 29 (1) ◽  
pp. 51 ◽  
Author(s):  
S Fukai ◽  
JH Silsbury
Keyword(s):  
Carbon Dioxide ◽  
Growth Rate ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Carbon Dioxide Exchange ◽  
Dry Matter Yield ◽  
Area Index ◽  
Crop Growth Rate ◽  
Matter Production ◽  
Final Yield

A simple deterministic model to simulate the time course of potential dry matter growth by subterranean clover swards in the field is described. Relationships used in the model were obtained mainly from experiments in temperature-controlled glasshouses and from measurements of rate of carbon dioxide exchange in an assimilation chamber. Canopy carbon dioxide exchange rates in the light and in the dark are calculated in the model from leaf area index, total dry matter, air temperature, irradiance and the crop growth rate of the sward. Photosynthates are distributed among different parts of plants according to empirical relationships. The model can estimate the potential dry matter growth of swards grown at different levels of irradiance and at different temperatures. Dry matter yield of a crop growing in the field without limitation of water and mineral nutrients can be predicted to within 20% for 100 days of growth. Potential dry matter yield of pure subterranean clover swards at Adelaide is predicted by the model to be strongly influenced by the time of cessation of growth. If the growth is terminated in the middle of October, an early start to growth as well as a high plant density will be advantageous for a high final yield. On the one hand, if the growing season extends until late November, there will be only a small effect of time of commencement of growth on final yield. The model suggests that leaf area index is an important determinant of dry matter production up to about 200 g m-2, and that increased maintenance respiration at a dry matter yield above about 600 g m-2 results in a decreased growth rate. The effects of variation in irradiance and temperature on dry matter production at different growth stages are assessed. It is concluded from use of the model that the effects of temperature on crop growth rate depend on the amount of dry matter present and on the level of solar radiation.

A physiological analysis of the effect of sowing density on the growth rate of subterranean clover

1982 ◽  
Vol 33 (2) ◽  
pp. 213 ◽  
Author(s):  
J-L Prioul ◽  
JH Silsbury
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Growth Curves ◽  
Subterranean Clover ◽  
Crop Growth ◽  
High Density ◽  
Planting Density ◽  
Low Density ◽  
Response Curves ◽  
Crop Growth Rate

The initial planting density of subterranean clover swards is known to affect the subsequent crop growth rate in such a way that a low density crop reaches the same final yield as does one sown at high density. To explain this phenomenon, daily carbon influxes and effluxes were measured during the growth of 'low' and 'high' density swards in a constant environment. The growth characteristics of individual plants in the sward and the photosynthetic responses of individual leaves to light were measured during ontogeny. Good agreement was found between the growth curves reconstructed from daily carbon increment and growth curves previously derived from dry matter sampling. The crop growth rate of a low density sward was found to be higher than that of a high density sward, and this is shown to be due to a lower respiratory loss. The high respiration rate of a high density crop can be attributed to plant mortality when dry matter density is higher than 400 g m-2. The photosynthetic light response curves of individual leaves at the top of the canopy were not found to be affected by the initial planting density, which suggests that subterranean clover plants are extremely well adapted to growth under sward conditions.

Response of vulpia [Vulpia bromoides (L.) S. F. Gray and V. myuros (L.) C. C. Gmelin] and subterranean clover to rate and time of application of simazine

1991 ◽  
Vol 31 (6) ◽  
pp. 785 ◽  
Author(s):  
AR Leys ◽  
B Plater ◽  
WJ Lill
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Plant Density ◽  
Sandy Soils ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Time Of Application ◽  
Matter Production ◽  
Loam Soil ◽  
Clover Plant

The responses of vulpia [Vulpia bromoides (L.) S. F. Gray and V. myuros (L.) C. C. Gmelin] and subterranean clover (Trifolium subterraneum L.) to rate and time of application of simazine were compared on a red loam soil containing 1.8% organic matter and on sands containing 0.4 and 0.8% organic matter. In 1988 and 1989, applications of 0.50, 0.75 and 1.00 kg a.i./ha of simazine in late May-early June resulted in 96.4, 99.8 and 99.6% control of vulpia, respectively. Later applications in July-August, or earlier applications in April, were less effective. There were no differences in the levels of control obtained on the 2 soils, nor were there any differences in the susceptibility of V. bromoides or V. myuros to simazine. On the red loam soil simazine did not reduce subterranean clover plant density or dry matter production; however, severe reductions of both were recorded on the sandy soils. Reasons for the different responses, along with the potential for the use of simazine to control vulpia in subterranean clover pastures, are discussed in detail.

scholarly journals The Contribution by Leaves of Different Age to New Growth of Subterranean Clover Plants Following the Removal of a Sulphur Stress I. Origin and Distribution of Dry Matter

1972 ◽  
Vol 25 (6) ◽  
pp. 1147 ◽  
Author(s):  
D Bouma ◽  
EAN Greenwood ◽  
EJ Dowling
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Area Ratio ◽  
Assimilation Rate ◽  
Relative Growth ◽  
Net Assimilation ◽  
Nutrient Solutions

During the first 3 days after transfer of moderately sulphur-deficient plants (S1) to full nutrient solutions, the relative growth rate (Rw) was considerably lower than that of plants raised at higher sulphur levels (S2 and Sa). This was reflected in a lower leaf area ratio of the S1 plants, and particularly in a reduction of nearly 50% in the net assimilation rate (EA). Net losses in dry matter from younger emerged leaves and petioles accounted for 25% of the dry matter in new leaves and petioles of S1 plants produced during this period.

Studies in the wool production of grazing sheep. 1. Seasonal variation in feed intake, liveweight and wool production

1964 ◽  
Vol 4 (15) ◽  
pp. 392 ◽  
Author(s):  
GW Arnold ◽  
WR McManus ◽  
IG Bush
Keyword(s):  
Dry Matter ◽  
Subterranean Clover ◽  
First Year ◽  
Stocking Rate ◽  
Wool Production ◽  
Herbage Intake ◽  
Significant Difference ◽  
Digestible Organic Matter ◽  
Annual Grasses ◽  
Stocking Rates

A four year experiment is described in which Merino wethers were continuously grazed on Phalaris- subterranean clover pasture containing some annual grasses, at three rates for a year and at four rates in subsequent years. For the first year of the experiment a pasture of annual grasses and subterranean clover was also studied at three stocking rates. From the time that the eco-systems that were established reached an equilibrium there was rarely less than 2500 lb of herbage dry-matter an acre available on the lowest stocking rate and rarely more than 1000 lb an acre on the highest stocking rate. There was a significant difference in wool cut per head only in the first year ; over the last three years of the experiment it was slightly lower on the highest and lowest stocking rates than on the intermediate stocking rate. Wool production per acre was proportional to stocking rate. Large seasonal fluctuations were recorded in estimated digestible organic matter intake, liveweight, and wool production. Peaks of intake, liveweight gain, and wool production occurred in autumn and spring but at different dates at different stocking rates. At all but the highest stocking rate, wool production per unit time was lower in summer than in winter. Estimated herbage intake increased with decreasing availability of pasture. Digestibility of the diet, availability of pasture, and body condition of the sheep appeared to affect intake. Despite a higher estimated herbage intake on the higher stocking rate treatments, wool production was no higher.

Feed intake, liveweight gain and carcass traits of lambs offered pelleted annual pasture hay supplemented with flaxseed (Linum usitatissimum) flakes or algae (Schizochytrium sp.)

2017 ◽  
Vol 57 (5) ◽  
pp. 877 ◽  
Author(s):  
V. F. Burnett ◽  
J. L. Jacobs ◽  
S. Norng ◽  
E. N. Ponnampalam
Keyword(s):  
Growth Rate ◽  
Feed Intake ◽  
Dry Matter ◽  
Carcass Traits ◽  
Subterranean Clover ◽  
Carcass Weight ◽  
Dry Matter Intake ◽  
Control Treatment ◽  
Annual Ryegrass ◽  
Animal House

In southern Australia, pastures comprised of annual ryegrass may not meet the nutritional requirements of fast-growing (>250 g/day) lambs in summer–autumn (December–May). An animal house experiment was conducted from March to July 2010 to investigate the use of flaxseed and algae as two potential supplements to improve feed intake, liveweight gain and carcass traits in lambs. One hundred and twenty lambs (in two groups of 60) were fed one of four diets, pelleted annual pasture hay (subterranean clover and annual ryegrass) (T1); pelleted annual pasture hay + flaxseed flakes (T2); pelleted annual pasture hay + algae supplement (T3); pelleted annual pasture hay + flaxseed flakes + algae supplement (T4). All diets were provided on an ad libitum basis with individual feed intake measured daily and liveweight recorded weekly. Lambs offered the flaxseed flakes (T2) treatment grew faster (P < 0.05), had heavier (P < 0.05) carcass weights and greater (P < 0.05) GR fat depth (total tissue depth at 11th/12th rib, 110 mm away from midline) than lambs offered the T1 diet. Lambs offered algae supplement (T3) had lower dry matter intake but growth rate and carcass weight were not affected compared with lambs offered the T1 diet. Lambs offered both flaxseed flakes and algae supplement (T4) had greater (P < 0.05) GR fat than lambs offered the T1 diet. This experiment provides evidence that supplementing growing lambs with flaxseed flakes can increase dry matter intake, growth rate and GR fat depth. In contrast, supplementing with an algae supplement reduced dry matter intake but growth rate and carcass weight were similar to the control treatment.

Effects of sowing time and sowing density on the growth of subterranean clover at Adelaide

1977 ◽  
Vol 28 (3) ◽  
pp. 427 ◽  
Author(s):  
JH Silsbury ◽  
S Fukai
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Dry Matter ◽  
Plant Density ◽  
Subterranean Clover ◽  
Crop Growth ◽  
Growth Stages ◽  
Sowing Time ◽  
Area Index ◽  
Crop Growth Rate

Growth curves have been constructed for undefoliated swards of subterranean clover (cv. Woogenellup) established at three plant densities (1,2 and 4 x l03 plants per m2) at three times of the year (May, June and August). The swards grew without any apparent water stress, until early December. The time course of shoot dry matter increase is examined by the use of a logistic function and by the recognition of three growth stages. Maximum crop growth rates ranged from 10 to 15 gm-2 day-1. The rate decreased with increase in density but increased with lateness of sowing, so that the highest crop growth rate was obtained with the lowest plant density sown in August. Estimated end-of-season yields were independent of density but decreased from about 1500 g m-2 for May sowing to 1000 g m-2 for August sowing. Effects of sowing density on the growth pattern persisted throughout the whole season. Swards took 70–100 days to attain a leaf area index (LAI) of 3, after which crop growth rates were almost constant with time and independent of short-term fluctuations in the level of daily solar radiation and average daily temperature. Swards reached a maximum LAI of about 6, LAI being linearly related to the amount of shoot dry matter up to about 600 gm-2 independent of density and sowing time. No evidence was found of an optimal relationship between crop growth rate and LAI.It is concluded that end-of-season yield is independent of plant density above 1000 established plants per m2, and that swards established as late as August have the capacity to attain a yield of 10 tonnes ha-1 provided the growing season is extended.

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