Herbicide dose rate response curves in subterranean clover determined by a bioassay

1997 ◽  
Vol 37 (1) ◽  
pp. 67 ◽  
Author(s):  
G. A. Sandral ◽  
B. S. Dear ◽  
J. E. Pratley ◽  
B. R. Cullis
Keyword(s):  
Dose Rate ◽  
Field Tests ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Response Curves ◽  
Leaf Stage ◽  
Time Of Application ◽  
Herbicide Treatments ◽  
Highly Correlated ◽  
Major Factors

Summary. Herbicide dose response curves were developed for 5 herbicide treatments, MCPA, 2,4-DB, bromoxynil, MCPA + terbutryn and MCPA + diuron, when applied to 2 cultivars of subterranean clover (Trifolium subterraneum L.) in a glasshouse experiment. The effect of varying spraying time (14 May and 14 June) and leaf stage (3–4 v. 8–10 trifoliate leaves) at spraying was also examined. The dose rate multiple of the recommended rate required to reduce the clover herbage yield by 50% (I50) differed markedly between herbicide treatments. The 2 MCPA mixtures were the most phytotoxic with an I50 value between 0.45 and 0.83, bromoxynil and MCPA alone were intermediate. 2,4-DB was the least phytotoxic with an I50 value between 2.36 and 2.94 depending on cultivar and leaf stage at the time of application. The effect of leaf stage at spraying, time of spraying and cultivar on herbicide phytotoxicity was relatively small, the major factors being herbicide choice (which accounted for 83% of the variation in I50 values) and rate of herbicide applied. While there was differential cultivar tolerance to the herbicide 2,4-DB, there was no difference between the cultivars in their response to the other herbicide treatments. The phytotoxicity of the herbicides applied at either the 3–4 or 8–10 leaf stage in the glasshouse bioassay was highly correlated (r = 0.84, P<0.01) with previous estimates of phytotoxicity determined under field conditions, although slightly overestimated phytotoxicity compared with field tests. European Weed Research Council (EWRC) scores of herbicide damage in the glasshouse bioassay were found to be highly negatively correlated with dry matter yield losses in both the glasshouse (r = –0.78 to –0.98, P<0.001) and field (r = –0.72, P<0.001) and are therefore an acceptable alternative where destructive sampling is not practical. The EWRC scoring system was found to be more effective at quantifying damage where it was manifest as burning or stunting rather than as leaf distortion. The study indicated that a glasshouse herbicide bioassay is a useful technique for rapidly screening herbicides for phytotoxicity on subterranean clover.

Tolerance of subterranean clover cultivars and balansa clover to selective herbicides in Tasmania

1989 ◽  
Vol 29 (6) ◽  
pp. 785 ◽  
Author(s):  
PM Evans ◽  
RS Smith ◽  
JA Carpenter ◽  
TB Koen
Keyword(s):  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Matter Production ◽  
Seedling Regeneration ◽  
Trifoliate Leaf ◽  
Leaf Stage ◽  
Matter Production ◽  
Herbicide Treatments ◽  
Second Year

Fifteen cultivars of subterranean clover (Trifolium subterraneum L.) and 1 cultivar of balansa clover (Trifolium balansae Boiss.) were screened for tolerance to 2,4-DB, MCPA-Na salt, MCPA amine, bromoxynil and combinations of these herbicides. The clovers were sprayed at the 3-4 trifoliate leaf stage and dry matter production assessed in the following spring. All herbicides reduced clover dry matter production (DM). The least damaging herbicides to subterranean clover were bromoxynil (0.3 kg a.i./ha) and MCPA-Na salt (0.313 kg a.i./ha) which reduced DM production by 23 and 39% respectively. The most damaging were 2,4-DB (0.8 kg a.i./ha) and MCPA amine (0.313 kg a.i./ha) plus bromoxynil (0.3 kg a.i./ha) which reduced DM production by 62 and 56% respectively. The damage caused by MCPA-Na salt (0.5 kg a.i./ha) plus bromoxynil (0.3 kg a.i./ha) was intermediate, reducing clover production by 44%. Second year seedling regeneration was reduced across all herbicide treatments by 32%. Of the currently recommended cultivars, Trikkala was the most tolerant to herbicides, with an average reduction in DM of 37%. Bromoxynil was the herbicide tolerated best by cvv. Enfield, Karridale, Larisa, Mt Barker and Woogenellup. The most effective weed killing treatments were 2,4-DB plus bromoxynil and MCPA-Na salt (0.5 kg a.i./ha) plus bromoxynil(0.3 kg a.i./ha).

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.

Time application of superphosphate and the yield of pasture on an acid soil.

1961 ◽  
Vol 1 (2) ◽  
pp. 81
Author(s):  
KD McLachlan
Keyword(s):  
Acid Soil ◽  
Total Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
First Year ◽  
Botanical Composition ◽  
Time Of Application ◽  
Relative Ability ◽  
Main Effect ◽  
Earlier Application

Superphosphate was applied in summer (December) or in autumn (March) to an existing mixed pasture of subterranean clover (Trifolium subterraneum L.) and phalaris (Phalaris tuberosa L.), growing on apodsolic soil of p H 5.8. Time of application effects were recorded at the lowest level of applied phosphate. The main effect was on the botanical composition of the pasture. The summer application favoured clover, the autumn one grass. This effect is explained as a change in the relative ability of the species to compete for superphosphate. These results suggest how time and rate of application of superphosphate may be used to manage pasture composition. In the first year, when clover growth was encouraged, the earlier application also increased the total yield of pasture. In the second and third years, changes in the yield of grass were offset by changes ill the yield of clover and the effect of time of application on total pasture yield was not significant.

Differential tolerance of Trifolium subterraneum L. (subterranean clover) cultivars to broadleaf herbicides. 2. Seed yield and quality

1995 ◽  
Vol 35 (4) ◽  
pp. 475 ◽  
Author(s):  
GA Sandral ◽  
BS Dear ◽  
NE Coombes
Keyword(s):  
Seed Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Germination Percentage ◽  
Yield Response ◽  
Wagga Wagga ◽  
Herbicide Treatment ◽  
Herbicide Treatments ◽  
Saving Effect ◽  
Seed Yields

The effect of broadleaf herbicides on seed set by Trifolium subterraneum (subterranean clover) cultivars was examined at 2 sites (Wagga Wagga and Canowindra) over 2 years. Five commonly used herbicide treatments (bromoxynil, MCPA, 2,4-DB, MCPA + terbutryn, MCPA + diuron) were applied at 2 rates to 7 cultivars of subterranean clover. Significant site x cultivar x herbicide interactions were observed. Seed yields were either unaffected or depressed by up to 66% at the higher rainfall site (Canowindra), whereas at the lower rainfall site (Wagga Wagga) some herbicide x cultivar combinations showed increases in seed yield up to 115%. The increase in seed yield was greater at the lower herbicide rate. The variation in seed yield with herbicide treatment was largely a result of a change (P<0.001) in the number of seeds set (R = 0.94 at Wagga Wagga; R = 0.85 at Canowindra). Seed size was also correlated (P<0.001) with seed yield at both sites but explained less of the variation (R = 0.23 at Wagga Wagga; R = 0.47 at Canowindra). The reduction in herbage yield as a result of herbicide application was a poor indicator of the subsequent seed yield response at both sites. Cultivar Trikkala was consistently most tolerant to the herbicide treatments, showing either no change in seed yield at the wetter site or large increases in seed yield at the lower rainfall site. In contrast, the seed yield of Dalkeith was depressed by 2,4-DB at both sites in both years by 39-66%. Increases in seed yield, which were most pronounced in cultivars of midseason maturity (Trikkala, Junee, Seaton Park) and least in later maturing cultivars (Karridale, Clare) and in the very early flowering Dalkeith, were attributed in part to a water-saving effect of the herbicide treatments. Cultivar maturity ranking was negatively correlated (P<0.001) with seed yield (R=-0.73 at Wagga Wagga; R=-0.45 at Canowindra). The germination percentage of seed produced by the cultivars was unaffected by herbicide treatment, although the number of abnormal radicles formed by germinating seed was higher in the 2,4-DB and MCPA treatments.

The tolerance of three transgenic subterranean clover (Trifolium subterraneum L.) lines with the bxn gene to herbicides containing bromoxynil

2003 ◽  
Vol 54 (2) ◽  
pp. 203 ◽  
Author(s):  
B. S. Dear ◽  
G. A. Sandral ◽  
D. Spencer ◽  
M. R. I. Khan ◽  
T. J. V. Higgins
Keyword(s):  
Leaf Area ◽  
Seed Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Biochanin A ◽  
Leaf Stage ◽  
Agronomic Characteristics ◽  
Herbage Yield ◽  
Transgenic Lines

A bxn gene, coding for the nitilase enzyme that catalyses the detoxification of the herbicide bromoxynil, was inserted into subterranean clover (Trifolium subterraneum L. subsp. yanninicum). The agronomic characteristics of 3 transgenic lines (BXN 5, 7, 10) and their response to herbicides containing bromoxynil, were compared with that of the non-transgenic parent, cv. Gosse, in 1 glasshouse and 2 field experiments.The application of bromoxynil at 1.5 L/ha resulted in a 50% reduction in the spring herbage yield of the non-transgenic control but no reduction in BXN 5 and 7. The level of the phyto-oestrogens, genistein and biochanin A, in the leaf tissue were low in Gosse and the 2 transgenic lines, BXN 7 and 10, but the level of genistein increased significantly (P < 0.05) from 0.85% in Gosse to 1.43% dry weight in BXN 5, and biochanin A increased from 0.35% in Gosse to 0.73% in BXN 5. The application of the herbicides bromoxynil, bromoxynil+MCPA, and Jaguar (bromoxynil+diflufenican) at the cotyledon stage in a glasshouse study significantly reduced the leaf area of the non-transgenic Gosse, but did not reduce the leaf area of the 3 transgenic lines. When applied at the 4–5 leaf stage, the leaf area of Gosse was again reduced by all the herbicides, but only the bromoxynil+MCPA treatment reduced the leaf area of the transgenic lines relative to the control. The application of bromoxynil or Jaguar at the 4–5 leaf stage depressed the herbage yield of Gosse by about 62% compared with 0–24% in the 3 transgenic lines. In the field studies, BXN 5 and 10 had similar seed yields to Gosse in the absence of herbicide application, but the seed yield of BXN 7 was significantly less than the other 2 transgenic lines. The level of hard-seed in BXN 7 was also lower at 25% compared with 55–57% in the other transgenic lines and Gosse.These findings stress the need to carefully assess the agronomic qualities of transgenic lines prior to release as although tolerance to bromoxynil may be greatly increased by the bxn gene, other important agronomic characteristics, such as seed yield, hardseededness, and isoflavone content, may change as result of the gene or transformation process.

Differential tolerance of Trifolium subterraneum L. (subterranean clover) cultivars to broadleaf herbicides 1. Herbage yield

1995 ◽  
Vol 35 (4) ◽  
pp. 467 ◽  
Author(s):  
BS Dear ◽  
GA Sandral ◽  
NE Coombes
Keyword(s):  
Seedling Survival ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Yield Reduction ◽  
Herbicide Application ◽  
Herbicide Treatments ◽  
Herbage Yield ◽  
Relative Tolerance ◽  
Differential Cultivar ◽  
Rate Of Recovery

The differential tolerance of 7 Trifolium subterraneum (subterranean clover) cultivars to 5 broadleaf herbicide treatments applied at 2 rates was examined at 2 sites over 2 years. The herbicide treatments and the rate of active ingredient applied (kg a.i./ha) were 2,4-DB (0.8, 1.6), MCPA (0.5, 1.0), bromoxynil (0.28, 0.56), MCPA (0.15, 0.3) + terbutryn (0.275, 0.4125), and MCPA (0.25, 0.375) + diuron (0.25, 0.375). The herbage yield of all cultivars at 30 and 60 days after herbicide application (DAA) was suppressed by all herbicides except 2,4-DB at 60 DAA. There was marked variation in cultivar tolerance, with Trikkala being the most tolerant to all herbicides. Seaton Park was the most sensitive to MCPA + terbutryn, MCPA + diuron, and bromoxynil, while Karridale was the most sensitive to MCPA. Log10(sprayed yield) log10(unsprayed yield) was an appropriate measure of relative tolerance of cultivars to herbicide. While herbage yields and yield reduction due to the herbicides varied between sites and years, the effect of the herbicides and the relative responses of the cultivars were similar across years and sites. Herbage yield meaned over the 2 herbicide rates was reduced by 16-71% at 30 DAA depending on herbicide and cultivar, and by 445% at 60 DAA. A mixture of MCPA + terbutryn or MCPA + diuron caused the largest reduction in herbage (47-71%) at 30 DAA, while MCPA and 2,4-DB caused the smallest (16-56%) reduction. Neither the maturity ranking of the cultivar nor the cultivar vigour measured at 30 DAA influenced sensitivity to the herbicides. The rate of recovery (kg DM/ha.day) by the cultivars at 30-60 DAA was greatest in the MCPA, 2,4-DB, and bromoxynil treatments (80-120 kg DM/ha.day) and least in the MCPA + diuron treatment (71-84 kg DM/ha.day) and was not related to maturity ranking. Doubling the rate of herbicide increased herbage yield suppression and resulted in slower growth rates but did not affect seedling survival. The magnitude of the reduction in herbage yield has important implications for choice of herbicide and needs to be balanced against the likely loss due to weed competition. The identification of significant differential cultivar tolerance suggests that worthwhile improvements in tolerance can be achieved through plant breeding or selection.

The response to phosphate of two annual pasture species. I. Effect of the soil's ability to adsorb phosphate on comparative phosphate requirement

1975 ◽  
Vol 26 (1) ◽  
pp. 137 ◽  
Author(s):  
NJ Barrow
Keyword(s):  
Relative Effectiveness ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Lolium Rigidum ◽  
Response Curves ◽  
Wimmera Ryegrass ◽  
Pot Trial

Eleven soils which differed widely in their ability to adsorb phosphate were used in a pot trial to compare the response to phosphate by subterranean clover (Trifolium subterraneum L.) with that by Wimmera ryegrass (Lolium rigidum Gaud.). Response curves were fitted to the yields (log-transformed). The coefficients of the curves were used to calculate both the relative effectiveness of the phosphate and the phosphate required to give a given fraction of the increase in log yield due to phosphate. Overall, the phosphate requirement for the grass was less than for the clover but the two species were affected differently by the soil's ability to adsorb phosphate. The phosphate requirement for the clover increased more rapidly with increasing adsorption by the soil than the phosphate requirement for the grass.

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.

Sulfur requirements during early growth of Trifolium balansae, Trifolium subterraneum, Medicago murex, and Phalaris aquatica

1995 ◽  
Vol 35 (2) ◽  
pp. 199 ◽  
Author(s):  
A Pinkerton ◽  
PJ Randall
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Early Growth ◽  
Critical Values ◽  
Sand Culture ◽  
Published Data ◽  
Phalaris Aquatica ◽  
Critical Concentrations ◽  
Highly Correlated ◽  
Nutrient Solutions

Sulfur (S) requirements for early growth were determined for 3 legumes (Trifolium balansae, T. subterraneum, Medicago murex) and 1 grass (Phalaris aquatica). Plants were grown in sand culture in a glasshouse and supplied with nutrient solutions containing 6 rates of S (1-32 �g/mL). Legumes were supplied with nitrogen (N) at 168 �g/mL, and phalaris with 28 or 168 pg N/mL. Plants were sampled twice, the second sampling coinciding with flowering of the legumes. Diagnostic indices [total S (St), HI-reducible S (sulfate-S), oxidised S (S6+)], and ratios (sulfate-S/St, S6+/St) were derived for whole shoots (WS), youngest open leaves (YOL) of legumes, and youngest expanded blades (YEB) of the grass. The largest responses to S by the legumes were made by balansa clover and murex medic, which both outyielded subterranean clover, but subterranean clover was the most efficient user of S and had the lowest external S requirement. Concentrations of S6+ were always higher than concentrations of sulfate-S, but the 2 were highly correlated and much lower than St. No S fraction or plant part sampled was consistently superior as an indicator of S status. The larger relative increases and sharper breaks in gradient of the relationships between yield and sulfate-S or S6+ compared with St were offset by their greater relative variability. All indices were subject to Piper-Steenbjerg effects, although these did not seriously affect the critical values. Critical values of St and S6+ in YOL, St in WS of balansa clover, and S, and S6+ in WS of subterranean clover changed little up to 60 days after sowing, but it was necessary to know plant age when assessing the S status of murex medic or phalaris. Critical concentrations of S, in phalaris were little affected by N supply, but critical concentrations of sulfate-S and S6+ were higher with 28 than 168 �g N/mL. Critical values for subterranean clover agreed well with previously published data.

Effect of cultivar and grazing intensity in spring on shear and compression energies of dry mature subterranean clover (Trifolium subterraneum L.)

1997 ◽  
Vol 48 (8) ◽  
pp. 1199 ◽  
Author(s):  
Y. J. Ru ◽  
J. A. Fortune
Keyword(s):  
Flowering Time ◽  
Large Range ◽  
Grazing Intensity ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Plant Materials ◽  
Leaf Petiole ◽  
Dry Matter Digestibility ◽  
Highly Correlated ◽  
Shear Energy

Twenty-six cultivars of subterranean clover were divided into 3 maturity groups according to the flowering time and sown in 2 blocks with 4 replicates. The plots were grazed under 2 intensities (hard and lax) during the growing season. The proportions of leaf, petiole, stem, and burr before senescence, dry matter digestibility (DMD), herbage availability, and seed yield in summer were measured. The energies required to shear and compress the resultant dry mature plant materials were determined using an Instron material testing instrument. The results showed a large range for shear (11·3-18·2 kJ/m2) and compression energies (2·8-4·6 kJ/kg DM) among the 26 cultivars. Grazing intensity in spring did not affect shear energy (P > 0·05) but increased the compression energy of dry mature subterranean clover by 0·2 units (P < 0·05). The energy required to shear or compress plant materials was highly correlated with herbage availability, flowering time, proportions of leaf and petiole in the sward, and fibre content of the plant materials, with the relationships being modified by grazing intensity in spring. Compression energy was related to DMD of plants (r = -0·7) and shear energy did not account for a significant amount of variation in DMD.

Sign in / Sign up

Export Citation Format

Share Document