Change in stomatal resistance and water use in subterranean clover (Trifolium subterraneum L.) in response to broadleaf herbicides

1996 ◽  
Vol 47 (4) ◽  
pp. 625 ◽  
Author(s):  
BS Dear ◽  
GA Sandral ◽  
NE Coombes
Keyword(s):  
Water Use ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Stomatal Resistance ◽  
Herbicide Application ◽  
Herbicide Treatments ◽  
Daily Water ◽  
Saving Effect ◽  
Reduced Water

The effect of 5 broadleaf herbicides on the water use and stomatal resistance of 2 cultivars of subterranean clover (Trifolium subterraneum L.) was examined in a glasshouse study. The herbicide treatments 2,4-DB, MCPA, bromoxynil, MCPA+terbutryn, and MCPA+diuron were applied at 6 rates at 2 times (14 May, 14 June) to plants at 2 leaf stages (3-4 and 8-10 leaves). Each of the herbicides reduced water use by the clover within 24 h, the size of the reduction increasing with the rate of herbicide applied. The herbicide treatments MCPA+terbutryn, MCPA+diuron, and bromoxynil caused the largest reductions (44-52%) in total water use over the 30-day period when applied at the recommended rate, and MCPA and 2,4-DB the least reduction (16-22%). Stomatal resistance increased substantially within 2 days of application of each of the herbicides. The magnitude of the change differed with herbicide and increased with herbicide rate. The effect of the herbicides on stomatal resistance declined 10-20 days after herbicide application in all treatments except 2,4-DB, but stomatal resistance of all herbicide-treated plants was still higher than the control 30 days after herbicide application. The herbicides LICPA+terbutryn and LlCPA+diuron and bromoxynil caused the largest increase in stomatal resistance and 2,4-DB the least. Stomatal resistance was found to be highly negatively correlated with daily water use by the clover plants at 2 days (r = -0.84, P < 0.01) and 30 days (r = -0.88, P < 0.01) after herbicide application. All of the herbicides reduced the LA1 of the plants, the effect increasing as the herbicide rate increased. Herbicide and herbicide rate had the largest effect on both water use and stomatal resistance; the effect of cultivar, leaf stage, and spraying time accounted for a relatively small proportion of the variance. The findings support the hypothesis that some broadleaf herbicides can result in a water-saving effect in subterranean clover swards through increasing stomatal resistance and decreasing the LAI, thereby potentially reducing moisture stress during seed set.

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.

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.

scholarly journals Comparative effects of grazing, herbicide or forage conservation on barley grass content in Trifolium subterraneum L. clover-based pasture

2019 ◽  
Vol 70 (9) ◽  
pp. 800
Author(s):  
John W. Piltz ◽  
Simon J. Flinn ◽  
Leslie A. Weston
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Herbicide Application ◽  
High Quality ◽  
Harvest Timing

Barley grass (Hordeum spp.) is a relatively short lived annual that provides high quality grazing early in the season, but its seed heads cause contamination of wool and carcasses, and may irritate the mouth, eyes and nose of sheep. Treatments were imposed on established subterranean clover (Trifolium subterraneum L.) annual pasture in the same plots for three consecutive years (2015 to 2017) to evaluate changes in barley grass content. Treatments included: grazing alone (G), herbicide followed by grazing (HG), or a forage conservation harvest in early October, late October or early November consistent with an early silage harvest (ES), late silage harvest (LS) or hay cut (H). Grazing plus herbicide markedly reduced (P &lt; 0.05) barley grass numbers compared with all other treatments, but increased (P &lt; 0.05) the growth of annual ryegrass (Lolium rigidum L.). ES reduced (P &lt; 0.05) barley grass and increased (P &lt; 0.05) subterranean clover compared with H, but broadleaf weed content benefitted by LS in contrast to either ES or H. Although herbicide application was the most effective method for barley grass control, forage harvest timing could be used to beneficially manipulate pasture composition.

The growth of barley grass (Hordeum leporinum) in annual pasture. 3. Some factors affecting balance with subterranean clover (Trifolium subterraneum)

1968 ◽  
Vol 8 (35) ◽  
pp. 702 ◽  
Author(s):  
DF Smith
Keyword(s):  
Soil Nitrogen ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Nitrogen Addition ◽  
The Other ◽  
Early Start ◽  
Factors Affecting ◽  
Two Factors ◽  
Hordeum Leporinum

Mixed swards of barley grass (Hordeum leporinum) and subterranean clover (Trifolium subterraneum) of two densities were grown at two levels of nitrogen. Growth was started at two different times mid- April and mid-May-and at each time half the plots were subjected to moisture stress. The swards were harvested after nine weeks of growth. The survival of clover plants was reduced by an early start, moisture stress and nitrogen addition : much more so than barley grass. The root : shoot ratios of both species were calculated ; both showed some sensitivity to the time of break and moisture stress, and the grass was also affected by the other two factors. Total sward production and the ratios of clover to grass varied widely Grass daminance was favoured by moisture stress or a late break, and both of these factors tended to override the effect of higher soil nitrogen in determining clover-grass balance. Total sward production more dependent on density than any other factor, especially with the later start. Higher nitrogen was effective in boosting production only if the break was early and there was no moisture stress.

Monitoring ley pastures and their response to winter cleaning

2006 ◽  
Vol 46 (8) ◽  
pp. 1023 ◽  
Author(s):  
E. C. Wolfe ◽  
J. A. Paul ◽  
P. D. Cregan
Keyword(s):  
Rapid Development ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Total Biomass ◽  
Seedling Density ◽  
Bare Ground ◽  
Herbicide Application ◽  
Seeding Rate ◽  
The Impact ◽  
Legume Growth

The purposes of this study were to evaluate subterranean clover-based leys on farms and in experiments using several pasture parameters, and to assess the impact of winter cleaning on the productivity and botanical composition of clover swards. Annual pastures were monitored on a group of 5 farms in the Wagga district and compared with an experimental subterranean clover (Trifolium subterraneum L.) pasture. The major problem in the farm paddocks was a lack of legume biomass due to poor legume densities, a consequence of the use of the soft-seeded cultivar Woogenellup and a high content of grassy weeds. The farmers in the group were unaware of the tools, parameters and benchmarks for making quantitative pasture comparisons. In 2 experiments, a range of subterranean clover swards were generated through the use of cultivars, seeding rate and winter cleaning treatments, grazed at 15 sheep/ha and monitored for 3 years. Appropriate benchmark values for the seed pool of subterranean clover were 300–350 kg/ha in winter and 600–700 kg/ha in summer. On the basis of both winter production, a function of May seedling density (target >1000 seedlings/m2) and spring production, which depended on the cultivar maturity, Junee was superior at Wagga to either Dalkeith (earlier maturing) or Woogenellup (softer seeded). Winter cleaning, using selective herbicides (fluazifop, simazine) to remove grasses and weeds, was advantageous in achieving a high content (>90%) and productivity of subterranean clover, provided that the legume content of the pasture was at least 28%, or >20% of total ground area before herbicide application in winter. In winter-cleaned swards, legume growth increased by up to 80%, legume biomass was improved by up to 46% and legume content increased from <50 to >95%. The main disadvantages of winter cleaning were increased areas of bare ground and reduced total biomass for several weeks after herbicide application, and the rapid development of ryegrass that was resistant to at least 1 of the herbicides used. The strategic use of observations to monitor the performance of pastures and their response to management is discussed.

Pasture mixes with lucerne (Medicago sativa) increase yields and water-use efficiencies over traditional pastures based on subterranean clover (Trifolium subterraneum)

2016 ◽  
Vol 67 (1) ◽  
pp. 69 ◽  
Author(s):  
M. R. McCaskill ◽  
M. C. Raeside ◽  
S. G. Clark ◽  
C. MacDonald ◽  
B. Clark ◽  
...  
Keyword(s):  
Medicago Sativa ◽  
Water Use ◽  
Festuca Arundinacea ◽  
Dry Matter ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Dry Matter Production ◽  
Weed Invasion ◽  
Matter Production ◽  
Water Use Efficiencies

Pastures sown to lucerne (Medicago sativa L.) with a perennial non-legume could increase feed supply relative to traditional pastures based on subterranean clover (Trifolium subterraneum L.). Such mixtures might also be preferable to pure lucerne pastures, which are prone to weed invasion. Yield and water-use efficiency (harvested dry matter per unit evapotranspiration) of mixtures with lucerne or subterranean clover were compared a field experiment established under rainfed conditions at Hamilton, Victoria. Soil moisture and dry matter production were measured over 2 years. Treatments included chicory (Cichorium intybus L.), cocksfoot (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Shreb.) with either lucerne or subterranean clover; pure lucerne; and phalaris (Phalaris aquatica L.) and perennial ryegrass (Lolium perenne L.) with only subterranean clover. In the second year, dry matter production from lucerne mixtures exceeded that of equivalent mixtures with subterranean clover in spring, summer and winter. In spring, the lucerne component continued producing for longer than the clover component through its use of deeper stored soil water, and in summer, lucerne continued to grow slowly after the grass component had entered a drought-induced dormancy. In winter, the contribution from the lucerne component complemented, rather than competed with, that from the non-legume component. Water-use efficiencies during winter–spring ranged from 4 kg ha–1 mm–1 for chicory–clover to 27 kg ha–1 mm–1 for a fescue–lucerne mixture, and during summer–autumn from nil for cocksfoot–clover to 13 kg ha–1 mm–1 for a fescue–lucerne mixture. This study demonstrates that lucerne-based mixtures can increase forage supply per unit water use relative to traditional pastures based on subterranean clover.

Effect of grazing strategy, ryegrass overdrilling and herbicide application on vulpia content, tiller density and seed production in perennial pastures

2008 ◽  
Vol 48 (5) ◽  
pp. 632 ◽  
Author(s):  
K. N. Tozer ◽  
D. F. Chapman ◽  
P. E. Quigley ◽  
P. M. Dowling ◽  
R. D. Cousens ◽  
...  
Keyword(s):  
Soil Seed Bank ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Integrated Approach ◽  
Annual Rainfall ◽  
Herbicide Application ◽  
Effective Strategies ◽  
Annual Grasses ◽  
Western Victoria ◽  
Tiller Density

Vulpia species C.C. Gmel. are annual grass weeds that can reduce the productivity of perennial pastures throughout southern Australia. To develop more effective strategies to manage vulpia, a 3-year experiment was established in western Victoria (average annual rainfall: 625 mm) comparing different methods currently used to control this weed. Overdrilling perennial ryegrass (Lolium perenne L.) seed and simazine application treatments were applied to phalaris (Phalaris aquatica L.) pastures that were set-stocked or rotationally grazed (either as a four-paddock or strategic rotation) with Merino ewes. The content of vulpia, subterranean clover (Trifolium subterraneum L.) and other annual grasses as a proportion of total dry matter increased, and the proportion of phalaris decreased in most grazing treatments throughout the experiment. The mean vulpia content was lowest and the phalaris content was highest in the four-paddock rotation, whereas vulpia content was greatest and phalaris content was lowest under set-stocking. Simazine application in June with or without ryegrass overdrilling reduced the number of vulpia tillers/m2 in 2000 and 2001 and vulpia panicle production in 2000, although vulpia populations increased to pretreatment levels in herbicide-treated swards by 2002. The number of vulpia seeds in the soil seed bank was not affected by any of the treatments. The most effective treatment was a combination of ryegrass overdrilling and herbicide application in the four-paddock, rotationally grazed pastures. This experiment highlights the need for an integrated approach to manage vulpia since relying on herbicide application alone is ineffective. This is particularly the case when competitive pasture species are unable to adequately utilise available resources and prevent a recovery in vulpia populations.

The inhibitory effect of light on seed development in subterranean clover (Trifolium subterraneum L.)

1976 ◽  
Vol 27 (2) ◽  
pp. 207 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Seed Development ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Inhibitory Effect ◽  
Atmospheric Moisture ◽  
Dark Treatment ◽  
Poor Seed ◽  
Development Processes ◽  
Effect Of Light

Explanations were sought for the poor seed development commonly found in unburied burrs of subterranean clover. In the first of two experiments, the effects of light and of atmospheric moisture stress on seed development in subterranean clover (cv. Daliak) were examined. Burrs produced from spaced laterals were enclosed in plastic tubes variously shaded to permit the entry of 0, 5, 19, 48 and 100% daylight. The tubes were further allocated to two groups. Air was continuously passed through tubes of one group to produce an atmospheric moisture stress, while those of the other group were not subjected to air flow. There was a marked effect of light on seed development. Mean seed weight was reduced from c. 11 mg in the dark treatment to 4 mg at only 5% daylight and to 2 mg in the 100% daylight treatment. Seed numbers were reduced significantly, from four to c. two seeds per burr, in the 100% daylight treatment only. There was virtually no effect of atmospheric moisture stress on either seed set or seed size. In the second experiment, a study was made of the effect of timing of burr burial on seed development processes. Fertilization does not appear to be implicated but both cell division and cell enlargement were influenced by the state of burial and, presumably, by light.

The effect of some environmental conditions on seed development and hard-seededness in subterranean clover (Trifolium subterraneum L.)

1979 ◽  
Vol 30 (1) ◽  
pp. 65 ◽  
Author(s):  
GB Taylor ◽  
MJ Palmer
Keyword(s):  
Seed Development ◽  
Seed Size ◽  
Field Experiments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moisture Stress ◽  
Effect Of Temperature ◽  
Temperature Regimes ◽  
Increasing Temperature ◽  
Dry Out

Subterranean clover (cv. Daliak) was grown in boxes with provision for unrestricted lateral growth. At the commencement of flowering, plants were allocated to three day/night temperature regimes of 12/7°, 18/13° and 24/19°C in controlled-temperature glasshouses and well watered until maturity (unstressed). In two additional treatments at 18/13°, plants were either subjected to intermittent moisture stress throughout the flowering period (stressed) or well watered for the first 6 weeks of flowering and then allowed to dry out (droughted). Increasing temperature resulted in more rapid inflorescence production, seed development and earlier plant maturation. The overall mean seed size was lower at 24/19° than at the other two temperatures. The stressed and droughted treatments produced fewer and smaller seeds than the corresponding unstressed treatment. There was a small effect of temperature on the degree of hard-seededness as determined from the mean softening time of seed subjected to daily alternating temperatures of 60/15°. Softening time was not significantly affected by watering treatments. There were small differences in softening time due to the position of the burr on the lateral, with a slight trend for seeds from the first-formed burrs to soften more rapidly. Most of the variation in softening time between seeds was due to variation within burrs. The sequence of seed softening within burrs was related to seed size, the larger seeds generally softening first, but no single regression could be used to describe this relationship for different burr positions or treatments. The absence of major treatment effects on the degree of hard-seededness indicates that varying the length of the seed development period does not necessarily result in differences in hard-seededness, as has been suggested from field experiments.

scholarly journals Rootstock Genotypes Shape the Response of cv. Pinot gris to Water Deficit

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 75
Author(s):  
Michele Faralli ◽  
Pier Lugi Bianchedi ◽  
Massimo Bertamini ◽  
Claudio Varotto
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Area ◽  
Water Use ◽  
Leaf Water Potential ◽  
Water Availability ◽  
Leaf Water ◽  
Daily Water ◽  
Shallow Soils ◽  
Reduced Water

Understanding the physiological basis underlying the water stress responses in grapevine is becoming increasingly topical owing to the challenges that climate change will impose to grapevine agriculture. Here we used cv. Pinot gris (clone H1), grafted on a series of tolerant (1103Paulsen; P), sensitive (SO4) and recently selected (Georgikon28; G28, Georgikon121; G121, Zamor17; Z17) rootstocks. Plants were either subjected to reduced water availability (WS) or maintained at pot capacity (WW). Photosynthetic (light response curves), stomatal and in vivo gas exchange analysis were carried out as well as dynamics of daily water use (WU), leaf area accumulation with affordable RGB imaging pipelines and leaf water potential. Significant genotypic variation was recorded between rootstocks for most of the traits analyzed under optimal conditions with P and SO4 showing a more vigorous growth, higher CO2 assimilation rate, stomatal conductance and stomatal density per unit of leaf area than G28, G121, Z17 (p < 0.001). Under WS, rootstocks induced different water stress response in Pinot gris, with G28 and G121 showing a higher sensitivity of water use to reduced water availability (WS) (p = 0.021) and no variation for midday leaf water potential until severe WS. P, Z17 and to some extent SO4 induced a pronounced near-anisohydric response with a general WU maintenance followed by reduction in leaf water potential even at high levels of soil water content. In addition, G28 and G121 showed a less marked slope in the linear relationship between daily water use and VPD (p = 0.008) suggesting elevated sensitivity of transpiration to evaporative demand. This led to an insensitivity for total dry weight biomass of G28 and G121 under WS conditions (p < 0.001). This work provides: (i) an in-depth analysis for a series of preferable traits under WS in Pinot gris; (ii) a characterization of Pinot gris × rootstock interaction and a series of desirable traits under WS induced by several rootstocks; (iii) the potential benefit for the use a series of affordable methods (e.g., RGB imaging) to easily detect dynamic changes in biomass in grapevine and quickly phenotype genotypes with superior responses under WS. In conclusion, the near-isohydric and conservative behavior observed for G28 and G121 coupled with their low vigor suggest them as potential Pinot gris rootstock candidates for sustaining grapevine productivity in shallow soils likely to develop terminal stress conditions.

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