Effect of times, height and frequency of defoliation on growth and development of Townsville stylo in pure ungrazed swards at Katherine, N.T

1973 ◽  
Vol 13 (63) ◽  
pp. 389 ◽  
Author(s):  
MJ Fisher

A one-year experiment was done in the field at Katherine, Northern Territory, to determine the influence of defoliation at different times (January, February, and March) and heights (5, 13 and 20 cm) on the growth and development of Townsville stylo (Stylosanthes humilis) in ungrazed swards grown with complete fertilizer and irrigation. Townsville stylo withstood repeated defoliation at 5 cm provided that cutting started in January, but, when the first defoliation was delayed, single cuts at 5 cm in either February or March killed 82 and 53 per cent of the swards. Defoliation to 5 cm early in the season reduced total cumulative yield by less than 450 kg ha-1, and did not affect pod yield or nitrogen and phosphorus concentrations at the end of the growing season. Immediately after defoliation nitrogen and phosphorus concentrations were reduced, but there was rapid recovery to higher levels with 5-cm and the same levels with 13-cm defoliation. Successive defoliation at 4 3 cm in February and March increased yield of pods. Defoliation at both 5 and 13 cm increased relative growth rate compared with the control and less frequently defoliated treatments. Defoliation to 5 cm each four weeks altered the stand morphology to a dense mat of foliage at cutting height. The ability of Townsville stylo to withstand continued defoliation suggests that sustained grazing during the growing season may be successful in controlling grass weeds vulnerable to grazing without greatly reducing pod yield or total dry matter production of Townsville stylo.


1970 ◽  
Vol 10 (47) ◽  
pp. 716 ◽  
Author(s):  
MJ Fisher

The effects of four levels of superphosphate (0, 112, 224, and 448 lb an acre) on the growth and development of ungrazed Townsville stylo (Stylosanthes humilis) in pure swards were examined on virgin Tippera clay loam at Katherine, N.T. Yields and distribution of dry matter, nitrogen, and phosphorus, leaf area, and growth rate, were measured every two weeks. Leaf relative water content and soil water extraction were measured at the end of the wet season. Yield responses to superphosphate were curvilinear and fitted regressions of the form y = a nx + bx + c at all harvests. Superphosphate encouraged root exploitation of the soil volume, but phosphorus deficient swards were more resistant to drought. The maximum recovery of phosphorus was 20, 14, and 14 per cent respectively when 112, 224, and 448 lb an acre superphosphate was applied. Loss of 31 per cent dry matter, 34 per cent nitrogen, and 44 per cent phosphorus in the eight weeks following maximum yield was concluded to be due to translocation to the root system. Even with 448 lb an acre superphosphate the phosphorus content of standing material was below the the critical percentage quoted in the literature as indicating phosphorus sufficiency.



1974 ◽  
Vol 14 (69) ◽  
pp. 495 ◽  
Author(s):  
JR Ive ◽  
MJ Fisher

Townsville stylo (Stylosanthes humilis) selections collected from twelve naturalized populations, in Queensland and the Northern Territory, and certified seed of the Katherine ecotype ('lines'), were grown for three years in a field experiment at Katherine, N.T. (latitude 14.3�S). In the third year, the experiment was oversown with Digitaria ciliaris. Flowering of all lines was delayed by late sowing, but was hastened by drought. However, the order in which the lines flowered was basically the same for all three years, and similar to that at Lansdown, Queensland (latitude 19.7�S). Although seasonally dependent, highest dry matter production was associated with erect mid- or late mid-season maturity lines which were often lowest in nitrogen and phosphorus concentration. There were no differences between lines in their ability to compete with Digitaria. Grazing reduced the proportion of grass in the swards compared with the forage harvested and non-defoliated treatments largely because Townsville stylo appeared to withstand grazing and trampling better than Digitaria.



1974 ◽  
Vol 14 (67) ◽  
pp. 182 ◽  
Author(s):  
Mannetje L t ◽  
KHLvan Bennekom

A midseason maturity type of Townsville stylo sown at monthly intervals throughout a year in a glasshouse in Brisbane (27�30' south) started flowering from 42 to 76 days after sowing between February and September, with dry matter yields at flowering ranging from 0.05 to 5.82 g/per plant. Sowings between October and January resulted in flowering after 98 to 157 days, with yields ranging from 26.41 to 54.75 g/per plant. Flowering was mainly determined by daylength, although low temperatures during winter delayed inflorescence elongation. Growth after onset of flowering was measured in plants sown in winter, spring and late summer. Plant weights increased after flowering in all sowings. In the spring sowing this consisted entirely of stem and inflorescence, but in the other sowings leaf was formed after onset of flowering as well. Winter and spring sowings gave the highest, late summer sowing the lowest final yields. The main agronomic implication is that sowing early in the growing season is necessary for obtaining a good first year's yield, but that seed production is little affected by sowing date, ensuring good regeneration even in years with a late start of the growing season.



1971 ◽  
Vol 22 (3) ◽  
pp. 369 ◽  
Author(s):  
CT Gates ◽  
WT Williams ◽  
RD Court

The effects of droughting and chilling on maturing Townsville stylo plants was assessed in terms of growth, seed and leaf shed, nitrogen, phosphorus, and amino acid composition. The major effect was due to droughting. Temperature participated as a small temperature-droughting interaction, in that cold reduced growth and increased proline under moist, but not under dry conditions. With droughting under warm conditions seed and leaf shed were increased and the nutrient content of seed was raised, which resulted in more of the plant's nitrogen and phosphorus being lost in these fractions. Droughting increased soluble nitrogen at the expense of protein nitrogen, but the amino acids fell as a proportion of the soluble nitrogen. The interrelations of nine amino acids were examined by multivariate techniques and it was shown that proline and aspartic acid behaved atypically, and that while other amino acids fell, proline increased some 10-fold under drought or cold stress. These effects indicate that soluble nitrogenous components may both increase and change in composition in the maturing plant as a result of stress, so rendering the plant more susceptible under field conditions to leaching or breakdown caused by dew or by slight showers of rain.



1975 ◽  
Vol 15 (72) ◽  
pp. 80 ◽  
Author(s):  
LA Edye ◽  
DF Cameron

Nine Stylosanthes humilis introductions from Brazil were compared with four Australian ecotypes and two mixtures when grown in swards with a grass Urochloa mosambicensis at two sites in the dry tropics of Queensland with an average growing season of 22 weeks per annum. The swards were harvested at 6-weekly intervals during the growing season at a height of 7.6 cm. Over the three years of the trial, no introduction was superior to cv. Gordon in dry matter and pod yield at the two sites. The Brazilian introductions showed variation in flowering times and growth habit. In general the later flowering, erect types were more productive because they made better growth late in the season, still set seed and competed better with sown grass. The naturalised Australian material gave higher pod yields but lower in vitro digestibilities during the dry season than the Brazilian introductions.



1977 ◽  
Vol 17 (84) ◽  
pp. 97 ◽  
Author(s):  
DF Cameron ◽  
RL McCown

The ecological adaptation of Townsville stylo (Stylosanthes humilis) lines was studied by following changes in the composition of mixtures of the lines. At Weipa, a high rainfall site in north Queensland, the composition of a mixture of four maturity types changed rapidly in favour of the later flowering lines, and the earliest line was almost eliminated by the end of the second year. In binary mixtures at 'Lansdown' near Townsville, defoliation every six weeks favoured erect lines but the proportion of prostrate lines was almost doubled at the three week cutting frequency. Changes in mixture composition could not be related to the dry matter yield or pod yield of the monocultures at either site. The capacity of late flowering lines to increase rapidly in populations growing in high rainfall areas, as demonstrated at the Weipa site, could pose problems for the commercial seed production of earlier flowering lines in such areas.



1990 ◽  
Vol 115 (3) ◽  
pp. 321-326 ◽  
Author(s):  
H. T. K. Kunelius

SUMMARYCultivars of Phleum pratense, Festuca pratensis, Festuca arundinacea, Dactylis glomerata and Lolium × Festuca hybrids were exposed to 4- and 3-cut harvest systems in Prince Edward Island, Canada, in 1985–87. Lolium perenne × F. pratensis, Lolium multiflorum × F. pratensis and L. multiftorum × F. arundinacea hybrids and D. glomerata had more uniform growth among the harvests than other grasses during the growing season. L. perenne × F. pratensis and L. multiflorum × F. pratensis had lower contents of neutral and acid detergent fibre than other grass cultivars, particularly early in the growing season. P. pratense cv. Farol had the lowest and L. perenne × F. pratensis cv. Prior the highest tiller population density. The stem apex of all cultivars was above the cutting height of 5 cm in c. 50% of tillers of primary growth. Leaf area per tiller was largest for P. pratense cv. Farol in the primary growth stage but differences were small in subsequent cuts.



1970 ◽  
Vol 10 (45) ◽  
pp. 442 ◽  
Author(s):  
KG Rickert ◽  
LR Humphreys

Townsville stylo (Stylosanthes humilis) was grown at Brisbane from February to June 1967 at initial densities of 10, 50, 250, 1250, and 6250 plants per m2 in boxes of sand which received basal nutrients and applications of 0, 10, and 50 kg P per hectare as calcium dihydrogen phosphate. Plots were irrigated frequently. Wide differences in dry matter yield between plant densities and a positive density phosphorus yield interaction persisted throughout the experiment. Peak yield was 1050 g per m2 with leaf area index (LAI) of 6.8. Intraspecific plant competition was evident in high densities 35 days after emergence, extending to the lower densities by 58 days. Plant mortality at the highest density was independent of phosphorus treatment. Maximum growth rates were reached earlier at high than at low plant densities ; the subsequent decreases in growth rate were expressed through drifts in both LA1 and NAR and were associated with progressively more unfavourable environmental conditions for growth. Nitrogen and phosphorus concentration of both shoots and roots decreased with increasing density. Phosphorus application did not affect nitrogen concentration. Exploitation of native soil phosphorus and recovery of applied phosphorus was greatest in high density swards. The data illustrate the loss in potential production which may occur in sparse swards of Townsville stylo and the limitations to efficient phosphorus response inherent in low density swards.



1977 ◽  
Vol 17 (88) ◽  
pp. 784 ◽  
Author(s):  
P Gillard

In experiments where Townsville stylo (Stylosanthes humilis) was oversown into perennial grass swards dominated by Heteropogon contortus and Bothriochloa bladhii residual stubble reduced the survival of Townsville stylo seedlings. When this stubble was removed, Townsville stylo plants grew to maturity and made up 25 per cent of the dry matter of the sward, an increase of 500 per cent Townsville stylo yield. Frequency of defoliation from 3 to 12 weeks during the growing season had no effect on the proportion of legume in the sward but the yield of all species was less under frequent cutting. Of the two collections of Townsville stylo used, the erect type always gave the highest yield and there was no evidence of an advantage for the prostrate type under frequent cutting. Over a period of three years the erect type invaded plots sown to the prostrate type. The response of Townsville stylo to superphosphate was large whereas that of the perennial native grasses was only slight.



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