Response of wheat cultivars to early post-emergence herbicides containing MCPA (2-methyl-4-chlorophenoxyacetic acid)

1987 ◽  
Vol 27 (1) ◽  
pp. 119 ◽  
Author(s):  
AR Leys ◽  
RB Hinkley ◽  
JA Fisher

In southern New South Wales in 1978 and 1979, the responses of 10 spring wheat cultivars to early post-emergence applications of MCPA, bromoxynil plus MCPA, and dicamba plus MCPA, were evaluated. The herbicides were applied at the rate recommended by their manufacturer (1x), and at 3 times this rate (3x). Cultivars differed in their responses to these treatments and herbicide tolerance was related to the stage of development of the apical meristem of the main tiller at the time of spraying. Olympic, Shortim and Egret were the most sensitive cultivars and their grain yield, averaged over rate and year, was reduced by 33, 19, and 15% respectively. Songlen, Jabiru and Durati were the most tolerant cultivars. Songlen was not affected by any herbicide, even when the 3x rates were used, while the grain yields of Jabiru and Durati were only reduced in 1 year, and then only by the 3x rate of dicamba plus MCPA. The remaining cultivars, Kite, Gamenya, Condor and Lance, were intermediate in their response to these herbicide treatments. Delaying the application of 1 of these herbicides, dicamba plus MCPA, until spikelet initiation, minimised yield reductions. Correlations between visual assessment of crop damage and grain yield reduction varied between cultivars and between herbicides.

1985 ◽  
Vol 25 (4) ◽  
pp. 922 ◽  
Author(s):  
D Lemerle ◽  
AR Leys ◽  
RB Hinkley ◽  
JA Fisher

Twelve spring wheat cultivars were tested in southern New South Wales for their tolerances to the recommended rates and three times the recommended rates of trifluralin, pendimethalin, tri-allate and chlorsulfuron. Recommended rates of these herbicides did not affect the emergence or grain yield of any cultivar. However, differences between cultivars in their tolerances to trifluralin, pendimethalin and chlorsulfuron at three times the recommended rate were identified. The extent of the reduction in emergence and/or grain yield varied with herbicide and season, and there was also a herbicidexseason interaction. Durati, Songlen and Tincurrin were the most susceptible cultivars to trifluralin, and Teal was the most tolerant. Yield losses from trifluralin were more severe in 1979 than in 1980 or 1981. The differential between cultivars treated with pendimethalin was smaller and more variable; Tincurrin was the only cultivar with a yield reduction in more than one season. Durati, Songlen and Shortim were the only cultivars affected by chlorsulfuron. A reduction in crop emergence of a cultivar treated with trifluralin or pendimethalin did not correlate consistently with any grain yield loss, and reductions in emergence were always greater than yield loss.


1985 ◽  
Vol 25 (3) ◽  
pp. 677 ◽  
Author(s):  
D Lemerle ◽  
AR Leys ◽  
RB Hinkley ◽  
JA Fisher ◽  
B Cullis

Sixteen spring wheat cultivars were tested in southern New South Wales for their tolerances to the recommended rates, and three times the recommended rates, and three times the recommended rates of barban, diclofop-methyl, difenzoquat and flamprop-methyl in 1978 and 1979. Differences between cultivars in their tolerances to barban and diclofop-methyl were identified in the grain yield responses to three times the recommended rates of these herbicides. Crop damage was more severe in 1978 than 1979. Olympic, Shortim, Teal and Warimba were consistently susceptible to barban, while Condor, Cook, Egret and Oxley were more tolerant than the other cultivars. The differences between cultivars treated with diclofop-methyl were smaller and variable. However, Lance, Teal and Tincurrin were the most sensitive whilst Cook, Kewell and Oxley showed the greatest tolerance. Visual assessments of crop damage did not accurately reflect crop tolerance, therefore grain yield should be used to identify susceptible cultivars.


1983 ◽  
Vol 34 (2) ◽  
pp. 99 ◽  
Author(s):  
BA Auld ◽  
DR Kemp ◽  
RW Medd

In four experiments, conducted over three contrasting seasons on the central western slopes of New South Wales, the grain yields of three wheat cultivars (Condor, Durati and Phoenix) sown in rhomboidal, square and rectangular patterns were compared with yields from traditionally sown (Poisson distribution along rows 180 mm apart) and broadcast arrangements. Square sowing resulted in significant (P < 0.05) yield increases (due to an increase in ear number) over rectangular arrangements in one experiment at three sowing densities 75,150 and 200 plants m-2. In two drier years there was no significant effect of arrangement at any density (40-400 plants m-2) in any one experiment. There was, however, a consistent significant (P < 0.05) trend over all experiments over 3 years, described by a response surface, of decreasing yield with increasing rectangularity as density was decreased. It is postulated that this was due to reduced ability of the plants to utilize available space. Traditional (sown in three seasons) and broadcast (sown in one season) arrangements produced yields which were not significantly (P > 0.05) different from the highest yielding treatments. It was concluded that there is no advantage in changing from the traditional sowing pattern to any precise geometric pattern. However, in precision sowing, rectangular patterns will result in lower yields than square patterns as density decreases from 200 plants m-2.


2009 ◽  
Vol 49 (10) ◽  
pp. 769 ◽  
Author(s):  
K. G. McMullen ◽  
J. M. Virgona

In southern New South Wales, Australia, grazing wheat during the vegetative and early reproductive growth stages (typically during winter) can provide a valuable contribution of high quality feed during a period of low pasture growth. This paper reports results from a series of experiments investigating the agronomic management of grazed wheats in southern NSW. The effect of sowing date and grazing on dry matter production and subsequent grain yield of a range of wheat cultivars was measured in five experiments in 2004 and 2005. In all experiments, results were compared with ungrazed spring wheat (cv. Diamondbird). Grain yield of the best winter cultivar was either the same or significantly greater than the spring cultivar in each of the five experiments. Within the winter wheat cultivars, there was significant variation in grain yield, protein content and screenings, depending on site and year with the cultivar Marombi out-yielding all others. Interestingly, this cultivar usually had the least dry matter post-grazing but the greatest dry matter by anthesis of the winter wheats. Generally, if sowing of the winter wheat was delayed, then the effects on yield were small or non-existent. The results are discussed with respect to the benefits of incorporating grazing cereals into cropping programs in the medium rainfall zone of southern Australia.


1992 ◽  
Vol 32 (3) ◽  
pp. 345 ◽  
Author(s):  
JL Cooper

Field experiments over 2 seasons in the Macquarie Valley of central New South Wales compared yields under irrigation of 5 wheat varieties with a wide range of maturities sown from 8 April to 27 August.Early maturity wheats (Yecora and Avocet) sown prior to 6 May suffered frost damage, while the winter wheats (WW33G and Burgas) sown after 29 July were not fully vernalised and most tillers failed to produce heads. There was a curvilinear relation between time of sowing and grain yield. Excluding the treatments which suffered frost damage, the earliest time of sowing (8 April) produced the highest yield, with a 6.4% yield reduction between 8 April and 8 May. The yield reduction increased with later sowing date: 13.3, 19.3, and 26.5% during May, June, and July. Anthesis in mid September produced the highest yields for all varieties. Treatments which flowered earlier than mid September suffered frost damage. For each day later than 15 September that anthesis occurred, the mean yield fell by 1.3% or about 68 kg/ha.day. Date of anthesis had no detectable effect on the rate of individual grain growth (1.3 mg/grain.day), but the later anthesis occurred, the shorter the duration of grain development and the lower the final grain weight. Rising temperatures, not moisture stress, seems to be the factor causing the decline in yield with late sowing. This experiment was irrigated to eliminate moisture stress but the decline in yield was similar to that reported for dryland crops.


1974 ◽  
Vol 14 (66) ◽  
pp. 93 ◽  
Author(s):  
AD Doyle ◽  
H Marcellos

The influence of variation in time of sowing on grain yield in five wheat cultivars has been studied in the North West Slopes of New South Wales over the period 1967 to 1971. Highest grain yields were obtained when wheat was sown at the end of June so as to flower at the end of the first week in October. Reductions in relative grain yield of 5 to 7 per cent were recorded for each week that sowing was delayed after the end of June, or 9 to 13.5 per cent for each week that flowering was delayed after the first week in October. Lower grain yields from late sown crops were associated with lower leaf area duration after flowering which could account for 69 per cent of the variation in grain yield. Lower grain yields in early sown crops were associated with lower ear numbers which could be ascribed in part to the influence of frosts.


2015 ◽  
Vol 66 (4) ◽  
pp. 349 ◽  
Author(s):  
Julianne M. Lilley ◽  
Lindsay W. Bell ◽  
John A. Kirkegaard

Recent expansion of cropping into Australia’s high-rainfall zone (HRZ) has involved dual-purpose crops suited to long growing seasons that produce both forage and grain. Early adoption of dual-purpose cropping involved cereals; however, dual-purpose canola (Brassica napus) can provide grazing and grain and a break crop for cereals and grass-based pastures. Grain yield and grazing potential of canola (up until bud-visible stage) were simulated, using APSIM, for four canola cultivars at 13 locations across Australia’s HRZ over 50 years. The influence of sowing date (2-weekly sowing dates from early March to late June), nitrogen (N) availability at sowing (50, 150 and 250 kg N/ha), and crop density (20, 40, 60, 80 plants/m2) on forage and grain production was explored in a factorial combination with the four canola cultivars. The cultivars represented winter, winter × spring intermediate, slow spring, and fast spring cultivars, which differed in response to vernalisation and photoperiod. Overall, there was significant potential for dual-purpose use of winter and winter × spring cultivars in all regions across Australia’s HRZ. Mean simulated potential yields exceeded 4.0 t/ha at most locations, with highest mean simulated grain yields (4.5–5.0 t/ha) in southern Victoria and lower yields (3.3–4.0 t/ha) in central and northern New South Wales. Winter cultivars sown early (March–mid-April) provided most forage (>2000 dry sheep equivalent (DSE) grazing days/ha) at most locations because of the extended vegetative stage linked to the high vernalisation requirement. At locations with Mediterranean climates, the low frequency (<30% of years) of early sowing opportunities before mid-April limited the utility of winter cultivars. Winter × spring cultivars (not yet commercially available), which have an intermediate phenology, had a longer, more reliable sowing window, high grazing potential (up to 1800 DSE-days/ha) and high grain-yield potential. Spring cultivars provided less, but had commercially useful grazing opportunities (300–700 DSE-days/ha) and similar yields to early-sown cultivars. Significant unrealised potential for dual-purpose canola crops of winter × spring and slow spring cultivars was suggested in the south-west of Western Australia, on the Northern Tablelands and Slopes of New South Wales and in southern Queensland. The simulations emphasised the importance of early sowing, adequate N supply and sowing density to maximise grazing potential from dual-purpose crops.


2003 ◽  
Vol 86 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Catherine M Suttle ◽  
Reginald Wong ◽  
Philip J Anderton ◽  
Hanna J Kim ◽  
Joanne D Kim ◽  
...  

2003 ◽  
Vol 43 (1) ◽  
pp. 71 ◽  
Author(s):  
M. K. Conyers ◽  
C. L. Mullen ◽  
B. J. Scott ◽  
G. J. Poile ◽  
B. D. Braysher

The cost of buying, carting and spreading limestone, relative to the value of broadacre crops, makes investment in liming a questionable proposition for many farmers. The longer the beneficial effects of limestone persist, however, the more the investment in liming becomes economically favourable. We re-established previous lime trials with the aim of measuring the long-term effects of limestone on surface acidity (pH run-down), subsurface acidity (lime movement) and grain yield. The study made use of experiments where there was adequate early data on soil chemical properties and cereal yields. We report data from 6 trials located at 4 sites between Dubbo and Albury in New South Wales. The rate of surface soil (0–10 cm) pH decline after liming was proportional to the pH attained 1 year after liming. That is, the higher the pH achieved, the more rapid the rate of subsequent pH decline. Since yields (product removal) and nitrification (also acid producing) may both vary with pH, the post-liming pH acts as a surrogate for the productivity and acid-generating rate of the soil–plant system. The apparent lime loss rate of the surface soils ranged from the equivalent of nearly 500 kg limestone/ha.year at pH approaching 7, to almost zero at pH approaching 4. At commercial application rates of 2–2.5 t/ha, the movement of alkali below the layer of application was restricted. However, significant calcium (Ca) movement sometimes occurred to below 20 cm depth. At rates of limestone application exceeding the typical commercial rate of 2.5 t/ha, or at surface pH greater than about 5.5, alkali and Ca movement into acidic subsurface soil was clearly observed. It is therefore technically feasible to ameliorate subsurface soil acidity by applying heavy rates of limestone to the soil surface. However, the cost and risks of this option should be weighed against the use of acid-tolerant cultivars in combination with more moderate limestone rates worked into the surface soil.There was a positive residual benefit of limestone on cereal grain yield (either barley, wheat, triticale, or oats) at all sites in both the 1992 and 1993 seasons. While acid-tolerant cultivars were less lime responsive than acid-sensitive ones, the best yields were generally obtained using a combination of liming and acid-tolerant cultivars.The long-term residual benefits of limestone were shown to extend for beyond 8–12 years and indicate that liming should be profitable in the long term.


1966 ◽  
Vol 6 (21) ◽  
pp. 219 ◽  
Author(s):  
BB Fischer ◽  
DJ Swain ◽  
EB Boerema

Increased rice yield was obtained when the predominant grasses infesting rice fields in the Murrumbidgee irrigation areas of New South Wales were effectively controlled. Ordram (ethyl hexahydro-1 H-azepine-1-carbothioate) applied at pre-sowing and at post-emergence of the rice and grass, gave excellent control of grasses. Propanil, applied to vigorously growing barnyard grass in its 2-3 leaf stage of development, also gave very effective control. Ordram, applied at pre-sowing at less than two inches from the germinating rice seed in the soil of applied at pre-emergence in the water when the plumule of the germinating seed had to grow through the herbicide treated soil, reduced the density of the stand or the vigour of the rice seedlings.


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