Defoliation frequency and the response by white clover to increasing phosphorus supply 1. Leaf dry matter yield and plant morphology responses

1997 ◽  
Vol 48 (1) ◽  
pp. 111 ◽  
Author(s):  
D. K. Singh ◽  
P. W. G. Sale
Keyword(s):  
Leaf Area ◽  
White Clover ◽  
Dry Matter ◽  
Leaf Size ◽  
Plant Morphology ◽  
Application Rate ◽  
Leaf Number ◽  
Growth And Survival ◽  
Defoliation Frequency ◽  
P Supply

A glasshouse experiment was carried out to determine how an increasing P supply influences the growth and survival of white clover plants subjected to a range of defoliation frequencies. Treatments involved the factorial combination of P application rate (0, 30, 90, and 180 mg/pot) to a P-deficient Krasnozem soil and defoliation frequency (1, 2, or 4 defoliations over 36 days). The survival of P-deficient plants was threatened by the most frequent defoliation; their leaf area declined owing to a reduction in leaf number and individual leaf size with each successive defoliation. Increasing the P supply to 180 mg/pot reversed this downward trend as the high P plants were able to maintain leaf area by increasing leaf size and number. Increasing the frequency from 1 to 4 defoliations over the 36 days also changed the form of the leaf dry matter response to added P, from an asymptotic to a linear response. The P requirement of white clover for maximum leaf yield therefore increased under frequent defoliation. This effect was also apparent for a range of morphological measurements including stolon elongation rate, leaf area, root mass, leaf number, and stolon number, where the magnitude of the P response was consistently greater for frequently defoliated plants. Exceptions included stolon mass, which responded more to P addition under infrequent defoliation.

scholarly journals Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda

2012 ◽  
Vol 30 (2) ◽  
pp. 317-325 ◽  
Author(s):  
R.C. Souza ◽  
A.C. Dias ◽  
M.R.A. Figueiredo ◽  
F.E.B. Obara ◽  
P.J Christoffoleti
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Dry Matter ◽  
Area Ratio ◽  
Leaf Area Ratio ◽  
Leaf Number ◽  
Relative Growth ◽  
Absolute Growth Rate ◽  
Absolute Growth

The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.

The effect of cutting frequency and root segregation on the yield from perennial ryegrass-white clover associations

1967 ◽  
Vol 69 (3) ◽  
pp. 391-397 ◽  
Author(s):  
B. F. Bland
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Dry Matter ◽  
The Third ◽  
Nitrogen Yield ◽  
Cutting Frequency ◽  
Nitrogen Yields ◽  
Below Ground ◽  
The Mean ◽  
Defoliation Frequency

1. Dry-matter and nitrogen yields were recorded from perennial ryegrass-white clover associations which were defoliated 2, 4 or 6 times a year during the period 1963 to 1965.2. The average yearly output of dry matter was approximately 4000, 7000 and 6000 lb/acre for 1963, 1964 and 1965 respectively. Nitrogen harvested amounted to 132, 184 and 179 lb N/acre.3. The mean annual dry-matter yields from 2, 4 and 6 defoliations were 5300, 6100 and 6000 lb/acre and the corresponding figures for nitrogen yields were 112, 166 and 217 lb N/acre.4. Both segregation of the species below ground and increasing the defoliation frequency were responsible for higher contributions towards drymatter and nitrogen yield from the clover component.5. A comparison of the nitrogen yields between the plots with species segregated rather than integrated below ground suggests that the effects of underground nitrogen transference from 30–31 lb N/acre could first be demonstrated in the spring of the third year.

scholarly journals WHITE CLOVER CULTIVAR RESPONSES TO PHOSPHATE FERTILISERS OF DIFFERING SOLUBILITY

1988 ◽  
pp. 151-156
Author(s):  
A.D. Mackay ◽  
J.R. Caradus
Keyword(s):  
White Clover ◽  
Phosphate Rock ◽  
Dry Matter ◽  
Water Solubility ◽  
Partially Acidulated Phosphate Rock ◽  
Leaf Number ◽  
Monocalcium Phosphate ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Stolon Length

A glasshouse study investigated the dry matter response of Grasslands Kopu and Grasslands Tahora white clover, cultivars of differing origins and morphologies, to three phosphate fertilizers, monocalcium phosphate (MCP), partially acidulated phosphate rock (PAPR) and a reactive phosphate rock, North Carolina phosphate rock (NCPR), of differing water solubility. Kopu responded more rapldly and reached Its maximum dry matter yield at a lower phosphorus (P) level than Tahora when MCP and NCPR were the P fertilizers. With PAPR as the P fertilizer, their response was similar. The shoot dry matter response by Kopu to all three P sources was reflected more in leaf weight and size than leaf number or stolon length. In contrast Tahora responded to added P by increasing leaf number and stolon length to a much greater extent than Kopu. Keywords: Trifolium repens, monocalcium phosphate, partially acidulated phosphate rock, reactive phosphate rock.

scholarly journals Attributes related to seasonal herbage growth in white clover

2009 ◽  
Vol 66 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Omar Scheneiter ◽  
Beatriz Rosso ◽  
Mauro Corletto
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Leaf Size ◽  
Growth Patterns ◽  
Dry Matter Accumulation ◽  
Seasonal Growth ◽  
Local Populations ◽  
Appearance Rate ◽  
Leaf Appearance Rate ◽  
Leaf Appearance

When breeding temperate forage species is investigated, some attributes such as herbage accumulation and seasonal growth patterns have to be considered. To modify some of these traits, knowledge of the detailed process might be useful. In order to evaluate seasonal growth of contrasting white clover populations an experiment was carried out. Treatments were five cultivars and three local populations collected in Argentina. Weekly measures were taken during each season to calculate leaf appearance and flower appearance rates, stolon growing rate and dry matter (DM) net accumulation. Different germplasm of this species have different mechanisms for DM accumulation. Leaf size, more than leaf appearance rate, was the variable with most differences among germplasm and mostly related to dry matter accumulation. During spring and summer, inflorescences production had important effects on growing stolon rate, and differences among germplasm were evident. Some local populations showed favourable attributes that could be useful for breeding.

scholarly journals Dynamics of change of leaf attributes of Brussels sprouts in response to switches between high and low supply of nitrogen

1996 ◽  
Vol 44 (1) ◽  
pp. 31-42
Author(s):  
J. Vos ◽  
H. Biemond ◽  
P.C. Struik
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Leaf Growth ◽  
Leaf Size ◽  
Application Rate ◽  
Supply Rate ◽  
Brussels Sprouts ◽  
N Supply ◽  
High Treatment ◽  
Reverse Switch

In a greenhouse pot experiment with Brussels sprouts grown in sand, 4 treatments were compared: a control without N limitation, a continuously N-deficient control and 2 treatments with a switch from the high to the low supply or vice versa. All treatments received nutrient solution at 9 dates during the experiment. The high-N and low-N controls received 1.96 and 0.56 g/application, respectively. In the high-low treatment the switch from the higher to the lower application rate took place 57 days after planting (DAP) and in the low high treatment the reverse switch took place 85 DAP; these 2 treatments received the same total amount of N. Plant N concentrations changed rapidly upon changes in N supply regime. When the supply rate was increased, N concentration increased in leaves that had completed their expansion. Changes in leaf growth started about 15 days after the switch in N regime. Leaves that were expanding at the switch responded by increase in area when N supply increased without a change in mass, i.e. specific leaf area increased. Leaf areas and specific leaf area of expanding leaves decreased when the N supply became smaller. The control of leaf size during initiation and expansion is discussed.

scholarly journals Sweet Potato Canopy Morphology: Leaf Distribution

1990 ◽  
Vol 115 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Zana C. Somda ◽  
Stanley J. Kays
Keyword(s):  
Leaf Area ◽  
Sweet Potato ◽  
Ipomoea Batatas ◽  
Plant Density ◽  
Leaf Size ◽  
Progressive Increase ◽  
Leaf Number ◽  
Petiole Length ◽  
Plant Densities ◽  
Leaf Distribution

Changes in leaf distribution of the sweet potato [Ipomoea batatas (L.) Lam.] cultivar Jewel were assessed bi-weekly for 18 weeks at three plant densities (15, 30, and 45 cm × 96-cm spacing). The distribution of leaves on the branches and the timing at which leaf number stabilized were affected by the plant density. Plant density resulted in significant differences in the number of leaves and percentage of missing leaves during the growing season. Leaf number and total leaf area varied substantially in response to plant density, but individual lamina and petiole lengths and leaf area did not vary. Average petiole and leaf lengths and leaf size increased during the season, with the maximum length and area dependent on the type of branch on which the leaf was formed. Average petiole length per branch and the susceptibility to leaf loss increased with descending branch hierarchy (secondary branch < primary branch < main stem). Leaf losses after the 4th week tended to parallel a progressive increase in petiole length of new leaves, suggesting shading as a primary cause of leaf shedding and the loss of the oldest leaves first.

scholarly journals Leaf area of common bean genotypes during early pod filling as related to plant adaptation to limited phosphorus supply

2010 ◽  
Vol 34 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Roberto Santos Trindade ◽  
Adelson Paulo Araújo ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Common Bean ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Leaf Size ◽  
Net Assimilation Rate ◽  
Leaf Number ◽  
Growth Stages ◽  
Assimilation Rate ◽  
Plant Adaptation ◽  
Net Assimilation

Low phosphorus supply markedly limits leaf growth and genotypes able to maintain adequate leaf area at low P could adapt better to limited-P conditions. This work aimed to investigate the relationship between leaf area production of common bean (Phaseolus vulgaris) genotypes during early pod filling and plant adaptation to limited P supply. Twenty-four genotypes, comprised of the four growth habits in the species and two weedy accessions, were grown at two P level applied to the soil (20 and 80 mg kg-1) in 4 kg pots and harvested at two growth stages (pod setting and early pod filling). High P level markedly increased the leaf number and leaf size (leaf area per leaf), slightly increased specific leaf area but did not affect the net assimilation rate. At low P level most genotypic variation for plant dry mass was associated with leaf size, whereas at high P level this variation was associated primarily with the number of leaves and secondarily with leaf size, specific leaf area playing a minor role at both P level. Determinate bush genotypes presented a smaller leaf area, fewer but larger leaves with higher specific leaf area and lower net assimilation rate. Climbing genotypes showed numerous leaves, smaller and thicker leaves with a higher net assimilation rate. Indeterminate bush and indeterminate prostrate genotypes presented the highest leaf area, achieved through intermediate leaf number, leaf size and specific leaf area. The latter groups were better adapted to limited P. It is concluded that improved growth at low P during early pod filling was associated with common bean genotypes able to maintain leaf expansion through leaves with greater individual leaf area.

scholarly journals Effects of nitrogen on development and growth of the leaves of vegetables. 1. Appearance, expansion growth and life span of leaves of Brussels sprouts plants

1995 ◽  
Vol 43 (2) ◽  
pp. 217-232
Author(s):  
H. Biemond ◽  
J. Vos ◽  
P.C. Struik
Keyword(s):  
Leaf Area ◽  
Application Rate ◽  
Leaf Number ◽  
N Application ◽  
Brussels Sprouts ◽  
Leaf Emergence ◽  
N Application Rate ◽  
Pot Trials ◽  
Leaf Expansion Rate ◽  
Green Leaf Area

In greenhouse pot trials, Brussels sprouts cv. Icarus SG2004 plants were supplied with various amounts of N at different stages during growth. The rate of leaf emergence ranged from 0.39 to 0.72 per day and was significantly increased by increasing N application rate. Leaf expansion rate and mature leaf area increased with leaf number, reaching maximum values between leaf number 10 and 20 and decreasing subsequently. Plants receiving more N had a higher total green leaf area per plant, due to more and larger green leaves. Specific leaf area of all leaves declined gradually from 130-230 cmsuperscript 2/g (depending on experiment) at about 30 days after planting to 60 cmsuperscript 2/g at the end of the experiments and was usually significantly increased by increasing N application rate.

scholarly journals Incident Irradiance and Cupric Hydroxide Container Treatment Effects on Early Growth and Development of Container-grown Pawpaw Seedlings

2002 ◽  
Vol 127 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Kirk W. Pomper ◽  
Desmond R. Layne ◽  
Snake C. Jones
Keyword(s):  
Leaf Area ◽  
Growth And Development ◽  
Red Light ◽  
Leaf Size ◽  
Dry Weight ◽  
Leaf Number ◽  
The North ◽  
Landscape Plant ◽  
Total Plant ◽  
Cupric Hydroxide

The North American pawpaw [Asimina triloba (L.) Dunal] has great potential as a fruit crop or as a landscape plant. The influence of incident irradiance on pawpaw seedling growth and development in containers was examined in the greenhouse and outdoors. Root spiraling can be a problem for container-grown pawpaw seedlings; therefore, the influence of paint containing cupric hydroxide [Cu(OH)2] at 100 g·L-1 applied to the interior of containers on plant growth was also examined in a greenhouse environment. In pawpaw seedlings grown outdoors for 11 weeks, low to moderate shading levels of 28%, 51%, or 81% increased leaf number, total leaf area, and total plant dry weight (DW) compared to nonshaded seedlings. A shading level of 81% decreased the root to shoot ratio by half compared to nonshaded plants. Shading of 98% reduced leaf number, leaf size, and shoot, root, and total plant DW. Shading increased leaf chlorophyll a and b concentrations for pawpaw seedlings grown outdoors, while it decreased average specific leaf DW (mg·cm-2). In a separate greenhouse experiment, pawpaw seedlings subjected to shade treatments of 0%, 33%, 56%, 81%, or 98% did not respond as greatly to shading as plants grown outdoors. Greenhouse-grown plants had greater total and average leaf area under 33% or 56% shading than nonshaded plants; however, shading >56% reduced root, shoot, and total plant DW. Total shoot DW was greater in greenhouse grown plants with 33% shading compared to nonshaded plants. Pawpaw seedlings in control and most shade treatments (33% to 81%) in the greenhouse environment had more leaves and greater leaf area, as well as larger shoot, root, and total plant DW than seedlings in similar treatments grown outdoors. The greenhouse environment had a 10% lower irradiance, a 60% lower ultraviolet irradiance, and a significantly higher (1.23 vs. 1.20) red to far-red light ratio than the outdoors environment. Treatment of container interiors with Cu(OH)2 decreased total and lateral root DW in nonshaded seedlings, and it adversely affected plant quality by causing a yellowing of leaves and reduction of chlorophyll levels by the end of the experiment in shaded plants. Growth characteristics of pawpaw seedlings were positively influenced by low to moderate shading (28% or 51%) outdoors and low shading (33%) in the greenhouse. Seedlings did not benefit from application of Cu(OH)2 to containers at the concentration used in this study. Commercial nurseries can further improve production of pawpaw seedlings using low to moderate shading outdoors.

Effect of defoliation frequency on an irrigated perennial pasture in northern Victoria. 1. Seasonal production and sward composition

1997 ◽  
Vol 48 (6) ◽  
pp. 811 ◽  
Author(s):  
A. R. Lawson ◽  
P. W. G. Sale ◽  
K. B. Kelly
Keyword(s):  
Growth Rate ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Dry Matter ◽  
Early Spring ◽  
Defoliation Frequency ◽  
Clover Content ◽  
Pasture Yield ◽  
Clover Pasture ◽  
Ryegrass Growth

A field experiment was carried out to investigate whether changes in winter and post-winter defoliation frequency would increase the white clover content of an irrigated perennial ryegrass–white clover pasture in northern Victoria. Pastures defoliated every 4 weeks during winter had higher white clover growing point (stolon apices with at least 2 nodes) density at the end of winter than pastures defoliated every 8 weeks or those receiving a single defoliation after 16 weeks, but these differences did not affect the clover content in the spring. Reasons for this are suggested. Pastures defoliated at 8-week intervals in winter were the most productive over winter{early spring. Less frequent defoliation (4 v. 2 weeks) during the post-winter, September–May period reduced white clover growing point and perennial ryegrass tiller densities. However, the white clover growth rate during this period was increased by less frequent defoliation, whereas the ryegrass growth rate was reduced, resulting in an increase of 10% in the white clover content, and a 1·9 t dry matter (DM)/ha increase in total DM produced. This higher clover content and pasture yield during spring–autumn with less frequent defoliation has important implications for the management of irrigated perennial pastures for the dairy industry in northern Victoria.

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