Competition between wheat and brome grass in Western Australia

1987 ◽  
Vol 27 (2) ◽  
pp. 291 ◽  
Author(s):  
GS Gill ◽  
ML Poole ◽  
JE Holmes
Keyword(s):  
Western Australia ◽  
Soil Type ◽  
Field Experiments ◽  
Yield Loss ◽  
Wheat Yield ◽  
Exponential Model ◽  
Bromus Diandrus ◽  
Growing Conditions ◽  
Brome Grass ◽  
The Relationship

Brome grass (Bromus diandrus Roth) has become a serious weed of wheat in Western Australia, particularly on light textured soils. Six field experiments were carried out to investigate competition between brome grass and wheat. Results showed that brome grass is an extremely aggressive weed in wheat. Although the experimental sites varied considerably in soil type, rainfall and other growing conditions the relationship between brome grass and reduction in wheat yield was remarkably consistent across the sites. An exponential model was found to adequately describe yield loss due to competition with brome grass and will be used for extension purposes in Western Australia. An examination of yield contributing characters of wheat suggested that yield loss due to brome grass had been determined before the crop reached the grainfilling stage and such a result diminishes the importance of competition for water in wheat-brome grass mixtures.

Tolerance of wheat cultivars to metribuzin and implications for the control of Bromus diandrus and B. rigidus in Western Australia

1990 ◽  
Vol 30 (3) ◽  
pp. 373 ◽  
Author(s):  
GS Gill ◽  
DG Bowran
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Wheat Cultivars ◽  
Bromus Diandrus ◽  
Brome Grass

Field experiments were carried out in Western Australia to investigate the response of 9 wheat cultivars to metribuzin and to evaluate its potential for the control of Bromus diandrus and B. rigidus in wheat. The wheat cultivars differed significantly in their response to metribuzin; a South Australian cultivar (Blade) was markedly more tolerant than all other cultivars investigated. Metribuzin alone (100-150 g/ha) or as a tank-mix with pendimethalin, incorporated by sowing, combined reliable brome grass control with good crop safety when used on Blade. Post-emergence application of metribuzin was generally less effective on brome grass and more phytotoxic to the crop than incorporation by sowing. This herbicide-cultivar package gives farmers an opportunity to selectively control brome grass in wheat.

Comparative soil water, pasture production, and crop yields in phase farming systems with lucerne and annual pasture in Western Australia

2001 ◽  
Vol 52 (2) ◽  
pp. 295 ◽  
Author(s):  
R. A. Latta ◽  
L. J. Blacklow ◽  
P. S. Cocks
Keyword(s):  
Soil Water ◽  
Western Australia ◽  
Oil Content ◽  
Field Experiments ◽  
Crop Yields ◽  
Wheat Yield ◽  
Farming Systems ◽  
Yield Response ◽  
Grain Protein ◽  
Pasture Production

Two field experiments in the Great Southern region of Western Australia compared the soil water content under lucerne (Medicago sativa) with subterranean clover (Trifolium subterranean) and annual medic (Medicago polymorpha) over a 2-year period. Lucerne depleted soil water (10–150 cm) between 40 and 100 mm at Borden and 20 and 60 mm at Pingrup compared with annual pasture. There was also less stored soil water after wheat (Triticum aestivum) and canola (Brassica napus) phases which followed the lucerne and annual pasture treatments, 30 and 48 mm after wheat, 49 and 29 mm after canola at Borden and Pingrup, respectively. Lucerne plant densities declined over 2 seasons from 35 to 25 plants/m2 (Borden) and from 56 to 42 plants/m2 (Pingrup), although it produced herbage quantities similar to or greater than clover/medic pastures. The lucerne pasture also had a reduced weed component. Wheat yield at Borden was higher after lucerne (4.7 t/ha) than after annual pasture (4.0 t/ha), whereas at Pingrup yields were similar (2 t/ha) but grain protein was higher (13.7% compared with 12.6%) . There was no yield response to applied nitrogen after lucerne or annual pasture at either site, but it increased grain protein at both sites. There was no pasture treatment effect on canola yield or oil content at Borden (2 t/ha, 46% oil). However, at Pingrup yield was higher (1.5 t/ha compared to 1.3 t/ha) and oil content was similar (41%) following lucerne–wheat. The results show that lucerne provides an opportunity to develop farming systems with greater water-use in the wheatbelt of Western Australia, and that at least 2 crops can be grown after 3 years of lucerne before soil water returns to the level found after annual pasture.

Carrier Volume Affects Wheat Response to Simulated Glyphosate Drift

2008 ◽  
Vol 22 (3) ◽  
pp. 453-458 ◽  
Author(s):  
Christopher A. Roider ◽  
James L. Griffin ◽  
Stephen A. Harrison ◽  
Curtis A. Jones
Keyword(s):  
Seed Weight ◽  
Field Experiments ◽  
Yield Loss ◽  
Wheat Yield ◽  
Yield Reduction ◽  
Usage Rate ◽  
Height Reduction ◽  
Herbicide Concentration ◽  
Glyphosate Drift ◽  
Carrier Volume

The influence of carrier volume was evaluated in field experiments for glyphosate applied to wheat at rates representing 12.5 and 6.3% of the usage rate of 1,120 g ai/ha (140 and 70 g/ha, respectively). Wheat at first node and at heading was exposed to glyphosate applied in a constant carrier volume of 234 L/ha, where herbicide concentration declined with reduction in dosage, and in proportional carrier volumes of 30 L/ha for the 12.5% rate and 15 L/ha for the 6.3% rate, where herbicide concentration remained constant. At 28 d after treatment, glyphosate applied at first node in proportional carrier volume (an average for 30 and 15 L/ha adjusted proportionally to glyphosate rate) reduced wheat height 42% compared with 15% when glyphosate was applied in 234 L/ha. Height reduction was no more than 15% when glyphosate was applied at heading in 234 L/ha or in the proportional carrier volumes and at first node in 234 L/ha. Wheat yield was reduced 42% when glyphosate at 140 g/ha was applied in 234 L/ha but was reduced 54% for the same rate applied in proportional carrier volume. For 70 g/ha glyphosate, wheat yield was reduced 11% when applied in 234 L/ha, but was reduced 42% when the same rate was applied in proportional carrier volume. Wheat yield reduction was equivalent when glyphosate was applied in 234 L/ha at first node and at heading (29 and 24%, respectively), but yield reductions of 60% for first node application and 36% for heading application were observed when glyphosate was applied in a proportional carrier volume. When averaged across carrier volumes and glyphosate rates, the greater yield loss from application at first node was attributed to decreased number of spikelets per spike and seed weight per spike.

Volunteer Barley Interference in Spring Wheat Grown in a Zero-Tillage System

Weed Science ◽  
2007 ◽  
Vol 55 (1) ◽  
pp. 70-74 ◽  
Author(s):  
John T. O'Donovan ◽  
K. Neil Harker ◽  
George W. Clayton ◽  
Linda M. Hall ◽  
Jason Cathcart ◽  
...  
Keyword(s):  
Spring Wheat ◽  
Field Experiments ◽  
Yield Loss ◽  
Wheat Yield ◽  
High Rate ◽  
Initial Slope ◽  
Threshold Values ◽  
Economic Threshold ◽  
Economic Thresholds ◽  
The Impact

There is no published information on the impact of volunteer barley on wheat yield loss or on the economics of controlling barley with a herbicide. With the registration of imazamox-resistant wheat, it is now possible to control volunteer barley in wheat. Thus, the likelihood of growing wheat in rotation with barley may increase. Field experiments were conducted in 2003 and 2004 at Beaverlodge, Lacombe, and Edmonton, AB, Canada, and Saskatoon, SK, Canada, to determine the impact of volunteer barley on yield of imazamox-resistant spring wheat seeded at relatively low (100 kg ha−1) and high (175 kg ha−1) rates. Barley was seeded at different densities to simulate volunteer barley infestations. Regression analysis indicated that wheat-plant density influenced the effects of volunteer barley interference on wheat yield loss, economic threshold values, and volunteer barley fecundity among locations and years. Economic thresholds varied from as few volunteer barley plants as 3 m−2at Beaverlodge in 2003 and 2004 to 48 m−2at Lacombe in 2003. In most cases, wheat yield loss and volunteer barley fecundity were lower and economic thresholds were higher when wheat was seeded at the higher rate. For example, averaged over both years at Beaverlodge initial slope values (percentage of wheat yield loss at low barley density) were 4.5 and 1.7%, and economic threshold values of volunteer barley plants were 3 m−2and 8 m−2at low and high wheat seeding rates, respectively. Results indicate that volunteer barley can be highly competitive in wheat, but yield losses and wheat seed contamination due to volunteer barley can be alleviated by seeding wheat at a relatively high rate.

Relationship between scald (Rhynchosporium secalis) and losses in grain yield of barley in Western Australia

1985 ◽  
Vol 36 (5) ◽  
pp. 655 ◽  
Author(s):  
TN Khan ◽  
MF D'Antuono
Keyword(s):  
Grain Yield ◽  
Critical Point ◽  
Western Australia ◽  
Field Experiments ◽  
Yield Loss ◽  
Growth Stages ◽  
Point Model ◽  
Percentage Yield ◽  
The Mean ◽  
Ripe Stage

The three commonly used techniques, viz. critical point model, area under the curve and multiple linear regression, were applied to study the relationship between scald infection and grain yield in field experiments conducted during 1979-1983 in Western Australia. In the preliminary analysis leaf three from the top and the mean of the top three leaves were found to be best correlated with yield. The three models did not dilfer greatly, presumably owing to the high correlations between scald at the milky ripe stage and at the earlier growth stages. The critical point model was chosen because of its simplicity. Percentage yield loss in combined data from all experiments showed a significant correlation (P < 0.001) with scald at the milky ripe stage and defined percentage yield loss in cultivars Clipper and Stirling to be about one-third of the mean scald damage on leaves 1 (flag), 2 and 3 at g.s. 75. Due to the range of trials in this analysis, it was suggested that this relationship may be applied to estimate yield loss from survey data in other parts of southern Australia, where scald is endemic.

Effect of Wheat (Triticum aestivum) Row Spacing, Seeding Rate, and Cultivar on Yield Loss from Cheat (Bromus secalinus)

1990 ◽  
Vol 4 (3) ◽  
pp. 487-492 ◽  
Author(s):  
Jeffrey A. Koscelny ◽  
Thomas F. Peeper ◽  
John B. Solie ◽  
Stanley G. Solomon
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Growth Habit ◽  
Wheat Yield ◽  
Row Spacing ◽  
Juvenile Growth ◽  
Seeding Rate ◽  
Bromus Secalinus ◽  
Hard Red Winter Wheat ◽  
Red Winter Wheat

Field experiments were conducted in Oklahoma to determine the effects of row spacing, cultivar, seeding rate, and water or ammonium polyphosphate fertilizer injection in the row at seeding, on the competitiveness of hard red winter wheat with cheat. Decreasing row spacing from 23 to 8 cm increased yield of weed-free wheat at two of three locations and cheat-infested wheat in six of ten experiments. Increasing seeding rate from 265 to 530 seeds m-2increased wheat yield. Injecting water at 20 ml m-1of row at seeding did not increase wheat emergence or yield. Cheat seed production was not consistently suppressed by any one cultivar. Juvenile growth habit was unrelated to wheat competitiveness.

Yield losses in wheat from yellow spot: comparison of estimates derived from single tillers and plots

1982 ◽  
Vol 33 (6) ◽  
pp. 899 ◽  
Author(s):  
RG Rees ◽  
GJ Platz ◽  
RJ Mayer
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Yield Loss ◽  
Wheat Yield ◽  
Sprinkler Irrigation ◽  
Yellow Spot ◽  
Grain Number ◽  
Pyrenophora Tritici Repentis ◽  
Wheat Stubble ◽  
The Relationship

Losses in wheat yield associated with yellow spot (Pyrenophora tritici-repentis) have been examined in a field experiment where development of crop and disease were promoted with sprinkler irrigation. Different amounts of infected wheat stubble were applied to initiate epidemics in four treatments, while fungicide sprays were used to reduce the severity of yellow spot in a fifth treatment. The relationship between severity of yellow spot and the amount of infected stubble at first appeared to be linear but became more noticeably logarithmic as the epidemics progressed. Under conditions favouring disease development, a loss in grain yield of c. 49% was measured in the most severely diseased treatment relative to the sprayed treatment, with grain number per unit area and grain size both being reduced. The percentage loss in grain yield was less for main stems than for later heads. Regression analyses of disease severity with grain yield and its components using 50 main stems in each plot gave different estimates of yield loss, depending on the growth stage at which disease severity was assessed. These estimates of yield loss and those provided by a previously developed disease-loss relationship severely underestimated the overall loss in grain yield. However, there was better agreement between estimates derived from the regressions and loss in grain yield on main stems. Possible reasons for the discrepancies in estimates of loss in grain yield are discussed.

scholarly journals Wheat Yield Loss in a Two Species Competition with Emex australis and Emex spinosa

2016 ◽  
Vol 34 (1) ◽  
pp. 35-46 ◽  
Author(s):  
M.M. JAVAID ◽  
A. TANVEER ◽  
H.H. ALI ◽  
M.A. SHAHID ◽  
R.M. BALAL ◽  
...  
Keyword(s):  
Yield Components ◽  
Field Experiments ◽  
Yield Loss ◽  
Maximum Yield ◽  
Wheat Yield ◽  
Growth And Yield ◽  
Wheat Crop ◽  
Yield Losses ◽  
Weed Species ◽  
Emex Australis

Emex australis and E. spinosa are significant weed species in wheat and other crops. Information on the extent of competition of the Emex species will be helpful to access yield losses in wheat. Field experiments were conducted to quantify the interference of tested weed densities each as single or mixture of both at 1:1 on their growth and yield, wheat yield components and wheat grain yield losses in two consecutive years. Dry weight of both weed species increased from 3-6 g m-2 with every additional plant of weed, whereas seed number and weight per plant decreased with increasing density of either weed. Both weed species caused considerable decrease in yield components like spike bearing tillers, number of grains per spike, 1000-grain weight of wheat with increasing density population of the weeds. Based on non-linear hyperbolic regression model equation, maximum yield loss at asymptotic weed density was estimated to be 44 and 62% with E. australis, 56 and 70% with E. spinosa and 63 and 72% with mixture of both species at 1:1 during both year of study, respectively. It was concluded that E. spinosa has more competition effects on wheat crop as compared to E. australis.

scholarly journals A soil test for aluminium toxicity in acidic subsoils of yellow earths in Western Australia

1991 ◽  
Vol 42 (5) ◽  
pp. 875 ◽  
Author(s):  
SJ Carr ◽  
GSP Ritchie ◽  
WM Porter
Keyword(s):  
Grain Yield ◽  
Regional Differences ◽  
Management Practices ◽  
Field Experiments ◽  
Wheat Yield ◽  
Aluminium Toxicity ◽  
Mitigating Factors ◽  
Toxic Concentrations ◽  
The Relationship ◽  
Western Australian

Many of the yellow earths in the Western Australian wheatbelt have naturally acidic subsoils which can reduce the yield of wheat grown on them. Current methods of assessing soil acidity cannot identify which soils have subsoil acidity severe enough to restrict wheat yields. We conducted 53 field experiments at 34 sites in 5 regions over 3 years to determine the relationship between yield of wheat and several different indices for identifying subsoils with toxic concentrations of aluminium, Al. Initially, we identified that the concentration of aluminium, [All, in the soil solution and in 1 : 5 0.005 M KCl extracts of soil from the 15-25 cm layer was responsible for the majority of the decrease in wheat yield. The concentration of Al in a 1 : 5 0.005 M KCl extract in the 15-25 cm layer was well correlated with grain yield of wheat grown on yellow earth soils in the Merredin region, provided the soils had similar fertilizer treatments. The ratio [All : [Na] in a 1 : 5 0.005 M KCl extract was a better predictor than [All alone of grain yield of wheat grown on yellow earths in different regions and with different fertilizer practices. The three seasons had little effect on the correlation between yield and different soil indices. The correlations determined were strongly affected by regional differences, which were probably due to differing water supply and availability. The choice of toxicity index depended on the uniformity of fertilizer management practices within a region and it appeared that both ionic strength and calcium were important mitigating factors.

Relationships between stripe rust severity and grain yield loss at Dooen, Victoria

1988 ◽  
Vol 39 (4) ◽  
pp. 563 ◽  
Author(s):  
JS Brown
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Stripe Rust ◽  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Rust Severity ◽  
Cent Disease ◽  
The Relationship ◽  
Best Estimator

The relationship between stripe rust severity and grain yield loss in wheat was studied in two field experiments. Wheat cultivars varying in response to the disease were used to produce epidemics of differing severity. Regression models were used to examine the relationship between disease severity and yield loss. The best estimator of yield loss was an estimate of disease severity at the end of anthesis-early berry growth stage. The relationship between per cent yield loss (YL) and per cent disease severity (DS) at that growth stage was established to be YL = 0.479DS + 0.84.

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