A re-evaluation of chlormequat application to wheat in Western Australia

1986 ◽  
Vol 26 (3) ◽  
pp. 361
Author(s):  
MW Perry ◽  
DJ Miers
Keyword(s):  
Grain Yield ◽  
Western Australia ◽  
Field Experiments ◽  
Leaf Growth ◽  
Maximum Yield ◽  
Growth Stages ◽  
Time Of Application ◽  
Natural Rainfall ◽  
Application Rates ◽  
Yield Responses

The effect of chlormequat on the grain yield of wheat was investigated in 24 field experiments between 1981 and 1983. Two times of application (at the 3.5- and 6-leaf growth stages-Zadoks decimal score 13.5 and 16.0) and rates of application up to 0.75 kg/ha a.i. were tested with two chlormequat formulations, Cycocel 750 and Bettaquat. Chlormequat application reduced crop height in all trials, but crop lodging did not occur in any trial. Statistically significant yield responses to rate of application alone were obtained in only three of 24 trials, with maximum yield occurring at 0.19-0.37 kg/ha a.i. and with some indication of a yield depression at 0.75 kg/ha a.i. A significant effect of time of application was observed in only two trials, but the results conflicted. In one trial there was a significant interaction between rate and time, with a response to rate of chlormequat only at the 6-leaf stage. No differences were detected between chlormequat formulations. In individual trials, the mean grain yield from the chlormequat treatments ranged from 92.9 to 116.5% of the control. However, averaging over all trials in each year, chlormequat treatments yielded 102.5, 99.3 and 100.0% of the control, respectively, in the three years. Our results confirm that low application rates of chlormequat, applied early in crop development, can increase grain yield. However, over the 24 trials, the effects of chlormequat were too small and inconsistent to warrant its use to increase wheat grain yields under natural rainfall in south-western Australia.

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.

Residual value of molybdenum for wheat production on naturally acidic soils of Western Australia

2006 ◽  
Vol 46 (10) ◽  
pp. 1333 ◽  
Author(s):  
R. F. Brennan
Keyword(s):  
Grain Yield ◽  
Western Australia ◽  
Field Experiments ◽  
Relative Effectiveness ◽  
Growth Stages ◽  
Eastern Region ◽  
Residual Value ◽  
Wheat Roots ◽  
Agricultural Areas ◽  
Tissue Test

Naturally acidic sandplain soils in the lower rainfall (<350 mm annual average) eastern region of the agricultural areas of south-western Australia are deficient in molybdenum (Mo) for grain production of wheat. Liming soils ameliorates Mo deficiency, but it is not an economic option for these soils because they are naturally acidic at soil depths commonly explored by wheat roots. Consequently, Mo fertiliser, usually as Mo trioxide, needs to be applied to wheat on these soils. The residual value of the Mo fertiliser for these soils was not known, so was measured using grain yield of wheat in 2 long-term field experiments. The Mo fertiliser treatments were applied once only in different years to plots not treated with Mo in a previous year. In both experiments, the residual value of the fertiliser was measured in 1993. Thus, it was possible to determine the effectiveness of the fertiliser applied once only 1–11 years previously (previous Mo) relative to freshly applied (current) Mo applied in 1993. At both sites, a continuous decline in the effectiveness of previous Mo relative to current Mo was related to time of Mo–soil contact. In experiment 1, the effectiveness of previous Mo relative to current Mo decreased by about 40, 50, 60 and 70% when applied 2, 5, 7 and 11 years previously. In experiment 2, on a more acidic soil with a larger capacity to sorb Mo, the relative effectiveness of previous Mo decreased by about 60 and 80% for Mo applied 2 and 6 years previously. The concentration of Mo measured in youngest emerged leaf blades was related to 90% of the maximum shoot yield at the time of sampling (diagnostic critical tissue test value) and to 90% of the maximum grain yield (prognostic critical tissue test value). Irrespective of the growth stage of wheat, both critical diagnostic and prognostic values were about 0.07 mg Mo/kg. The concentration of Mo in grain that was related to 90% of the maximum grain yield was 0.02 mg/kg. The reapplication of Mo fertiliser to naturally acidic sands can be made with knowledge of the residual value and use of tissue testing for Mo, particularly when sampled at early growth stages of wheat.

Effect of Application Rate, Weed Species, and Weed Stage of Growth on Imazethapyr Activity

Weed Science ◽  
1992 ◽  
Vol 40 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Tracy E. Klingaman ◽  
Charles A. King ◽  
Lawrence R. Oliver
Keyword(s):  
Field Experiments ◽  
Leaf Growth ◽  
Application Rate ◽  
Leaf Number ◽  
Red Rice ◽  
Weed Species ◽  
Leaf Stage ◽  
Time Of Application ◽  
True Leaf ◽  
Application Rates

Field experiments were conducted in 1986, 1987, and 1988 to evaluate imazethapyr rate and time of application on postemergence control of 24 weed species. Contour graphs were developed that predicted imazethapyr rates required for various levels of weed control based upon weed leaf number at application. Rates below the labeled rate (70 g ha−1) provided 90% or greater control of common cocklebur, smallflower morningglory, and smooth pigweed if applied to 3 true-leaf or smaller weeds and of barnyardgrass, seedling johnsongrass, and Palmer amaranth if applied while weeds were in the cotyledon or 1 true-leaf stage. A rate of 70 g ha−1provided 90% control of large crabgrass in the 1 true-leaf stage. Entireleaf morningglory, red rice, pitted morningglory, and velvetleaf are not susceptible enough to imazethapyr for 90% or greater control to be obtained with rates lower than 70 g ha−1at the 1 true-leaf growth stage. These data demonstrate how control data can be used for developing effective reduced-rate herbicide recommendations based on weed leaf number.

Determining the fertiliser phosphorus requirements of intensively grazed dairy pastures in south-western Australia with or without adequate nitrogen fertiliser

2007 ◽  
Vol 47 (7) ◽  
pp. 801 ◽  
Author(s):  
M. D. A. Bolland ◽  
I. F. Guthridge
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Maximum Yield ◽  
Dairy Herd ◽  
Yield Response ◽  
Soil Test ◽  
Mineral N ◽  
P Leaching ◽  
The Many ◽  
Yield Responses

Fertiliser phosphorus (P) and, more recently, fertiliser nitrogen (N) are regularly applied to intensively grazed dairy pastures in south-western Australia. However, it is not known if applications of fertiliser N change pasture dry matter (DM) yield responses to applied fertiliser P. In three Western Australian field experiments (2000–04), six levels of P were applied to large plots with or without fertiliser N. The pastures were rotationally grazed. Grazing started when ryegrass plants had 2–3 leaves per tiller. Plots were grazed in common with the lactating dairy herd in the 6-h period between the morning and afternoon milking. A pasture DM yield response to applied N occurred for all harvests in all three experiments. For the two experiments on P deficient soil, pasture DM yield responses also occurred to applications of P. For some harvests when no fertiliser N was applied, probably because mineral N in soil was so small, there was a small, non-significant pasture DM response to applied P and the P × N interaction was highly significant (P < 0.001). However, for most harvests there was a significant pasture DM response to both applied N and P, and the P × N interaction was significant (P < 0.05–0.01), with the response to applied P, and maximum yield plateaus to applied P, being smaller when no N was applied. Despite this, for the significant pasture DM responses to applied P, the level of applied P required to produce 90% of the maximum pasture DM yield was mostly similar with or without applied N. Evidently for P deficient soils in the region, pasture DM responses to applied fertiliser P are smaller or may fail to occur unless fertiliser N is also applied. In a third experiment, where the soil had a high P status (i.e. more typical of most dairy farms in the region), there was only a pasture DM yield response to applied fertiliser N. We recommend that fertiliser P should not be applied to dairy pastures in the region until soil testing indicates likely deficiency, to avoid developing unproductive, unprofitable large surpluses of P in soil, and reduce the likelihood of P leaching and polluting water in the many drains and waterways in the region. For all three experiments, critical Colwell soil test P (a soil test value that was related to 90% of the maximum pasture DM yield), was similar for the two fertiliser N treatments.

Yield responses of wheat and other crops to agronomic practices on duplex soils compared with other soils in Western Australia

1992 ◽  
Vol 32 (7) ◽  
pp. 963 ◽  
Author(s):  
WK Anderson ◽  
RJ French ◽  
M Seymour
Keyword(s):  
Grain Yield ◽  
Water Use ◽  
Western Australia ◽  
Management Practices ◽  
Maximum Yield ◽  
Experimental Results ◽  
Agronomic Practices ◽  
Use Efficiency ◽  
Yield Responses ◽  
Applied Nitrogen

A survey of experimental results relating crop management to grain yield was conducted for wheat and other crops on duplex and non-duplex soils in the wheatbelt of Western Australia. Increases in grain yield of wheat due to improved agronomic practices on duplex soils were almost as great as on other soils. Early sowing improved yield more on duplex soils than on other soils, but the response to applied nitrogen was more variable, possibly related to the reduced efficiency of uptake of applied nitrogen. The yield advantage for a semi-dwarf cultivar (Aroona) over a tall cultivar (Garnenya) was less (6%) on duplex soils than on other soils (29%). The optimum seed rate was 27% greater on duplex than on other soils. Increases in both grain yield and grain quality due to the application of potassium were large on 1 duplex soil. Water use efficiency in grain production was similar on duplex and other soils where seasonal water use did not exceed about 350 mm. At 1 location in the eastern wheatbelt, yields of wheat, barley, lupins and peas grown on a duplex soil were compared with yields on 2 other soils. Wheat was the most productive crop on the duplex soil, while barley yielded most on the other soils. All crops, except lupins, yielded less on the duplex soil. Experiments with 2 lupin cultivars grown on duplex and other soils on the south coast of Western Australia (average growing season rainfall >300 mm) showed that both cultivars yielded less on duplex soils, but 1 cultivar required slightly fewer plants to achieve its maximum yield on the duplex soils. This survey of experimental results in Western Australia shows that duplex soils are no less productive than other soils when results are averaged over all crops and locations. We conclude, however, that different management practices may be required to improve yields on duplex compared with other soils.

Influence of potassium and nitrogen fertiliser on yield, oil and protein concentration of canola (Brassica napus L.) grain harvested in south-western Australia

2007 ◽  
Vol 47 (8) ◽  
pp. 976 ◽  
Author(s):  
R. F. Brennan ◽  
M. D. A. Bolland
Keyword(s):  
Brassica Napus ◽  
Grain Yield ◽  
Western Australia ◽  
Field Experiments ◽  
Sandy Soils ◽  
Grain Production ◽  
Brassica Napus L ◽  
Grain Yields ◽  
Four Levels ◽  
Yield Responses

Most soils used for agriculture in south-western Australia are sandy and are now deficient in both potassium (K) and nitrogen (N) for cereal and canola (oilseed rape; Brassica napus L.) grain production. However, the effect of applying different levels of both fertiliser K and N on grain yields of these crops is not known. We report results of 10 field experiments, conducted on sandy soils in the region, to measure the effects of applying both K and N on canola grain yields and concentration of oil and protein in grain. Four levels of K (0–60 kg K/ha as potassium chloride) and four levels of N (0–138 kg N/ha as urea) were applied. Significant grain yield responses to applied N occurred in all experiments for the nil-K treatment and each level of K applied, with responses increasing as more N was applied. For all levels of N applied, significant grain yield responses occurred when up to 30 kg K/ha was applied, with no further significant grain yield responses occurring when 60 kg K/ha was applied. The K × N interaction was always significant for grain production. Application of K had no effect on the concentration of oil and protein in grain. Application of N consistently decreased concentration of oil and increased concentration of protein in grain. The K × N interaction was not significant for concentration of oil or protein in grain, but application of up to 30 kg K/ha significantly increased canola grain and so oil yields (concentration of oil in grain multiplied by grain yield). Our results are likely to be relevant for all acidic to neutral sandy soils worldwide used for growing canola crops.

Soil and tissue tests to predict pasture yield responses to applications of potassium fertiliser in high-rainfall areas of south-western Australia

2002 ◽  
Vol 42 (2) ◽  
pp. 149 ◽  
Author(s):  
M. D. A. Bolland ◽  
W. J. Cox ◽  
B. J. Codling
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Relative Yield ◽  
Subterranean Clover ◽  
Test Method ◽  
Yield Response ◽  
Soil Test ◽  
Test Procedures ◽  
Pasture Production ◽  
Yield Responses

Dairy and beef pastures in the high (>800 mm annual average) rainfall areas of south-western Australia, based on subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum), grow on acidic to neutral deep (>40 cm) sands, up to 40 cm sand over loam or clay, or where loam or clay occur at the surface. Potassium deficiency is common, particularly for the sandy soils, requiring regular applications of fertiliser potassium for profitable pasture production. A large study was undertaken to assess 6 soil-test procedures, and tissue testing of dried herbage, as predictors of when fertiliser potassium was required for these pastures. The 100 field experiments, each conducted for 1 year, measured dried-herbage production separately for clover and ryegrass in response to applied fertiliser potassium (potassium chloride). Significant (P<0.05) increases in yield to applied potassium (yield response) were obtained in 42 experiments for clover and 6 experiments for ryegrass, indicating that grass roots were more able to access potassium from the soil than clover roots. When percentage of the maximum (relative) yield was related to soil-test potassium values for the top 10 cm of soil, the best relationships were obtained for the exchangeable (1 mol/L NH4Cl) and Colwell (0.5 mol/L NaHCO3-extracted) soil-test procedures for potassium. Both procedures accounted for about 42% of the variation for clover, 15% for ryegrass, and 32% for clover + grass. The Colwell procedure for the top 10 cm of soil is now the standard soil-test method for potassium used in Western Australia. No increases in clover yields to applied potassium were obtained for Colwell potassium at >100 mg/kg soil. There was always a clover-yield increase to applied potassium for Colwell potassium at <30 mg/kg soil. Corresponding potassium concentrations for ryegrass were >50 and <30 mg/kg soil. At potassium concentrations 30–100 mg/kg soil for clover and 30–50 mg/kg soil for ryegrass, the Colwell procedure did not reliably predict yield response, because from nil to large yield responses to applied potassium occurred. The Colwell procedure appears to extract the most labile potassium in the soil, including soluble potassium in soil solution and potassium balancing negative charge sites on soil constituents. In some soils, Colwell potassium was low indicating deficiency, yet plant roots may have accessed potassum deeper in the soil profile. Where the Colwell procedure does not reliably predict soil potassium status, tissue testing may help. The relationship between relative yield and tissue-test potassium varied markedly for different harvests in each year of the experiments, and for different experiments. For clover, the concentration of potassium in dried herbage that was related to 90% of the maximum, potassium non-limiting yield (critical potassium) was at the concentration of about 15 g/kg dried herbage for plants up to 8 weeks old, and at <10 g/kg dried herbage for plants older than 10–12 weeks. For ryegrass, there were insufficient data to provide reliable estimates of critical potassium.

scholarly journals A műtrágyázás és a csapadék változékonyságának hatása a kukorica (Zea mays L.) termésére

2005 ◽  
Vol 54 (3-4) ◽  
pp. 309-324 ◽  
Author(s):  
László Márton
Keyword(s):  
Grain Yield ◽  
Maximum Yield ◽  
Maize Yield ◽  
Vegetation Period ◽  
Positive Effects ◽  
Experimental Station ◽  
Natural Rainfall ◽  
Zn Content ◽  
Set Up

The effect of natural rainfall and N, P and K nutrients on the yield of maize was investigated in 16 years of a long-term fertilization experiment set up at the Experimental Station of the Institute in Nagyhörcsök. The soil was a calcareous chernozem, having the following characteristics: pH (KCl): 7.3, CaCO 3 : 5%, humus: 3%, clay: 20-22%, AL-soluble P 2 O 5 : 60-80, AL-soluble K 2 O: 180-200, KCl-soluble Mg: 150-180; KCl+ EDTA-soluble Mn, Cu and Zn content: 80-150, 2-3 and 1-2 mg·kg -1 . The experiment had a split-split-plot design with 20 treatments in 4 replications, giving a total of 80 plots. The treatments involved three levels each of N and P and two levels of K in all possible combinations (3×3×2=18), together with an untreated control and one treatment with a higher rate of NPK, not included in the factorial system. The main results can be summarized as follows: An analysis of the weather in the 16 experimental years revealed that there were no average years, as two years were moderately dry (1981, 1982), eight were very dry (1973, 1978, 1986, 1989, 1990, 1993, 1997, 2002) and six were very wet (1969, 1974, 1977, 1994, 1998, 2001). In dry years the N, NP and NK treatments led to a yield increment of over 3.0  t·ha -1 (3.2 t·ha -1 ) (81%) compared with the unfertilized control, while the full NPK treatment caused hardly any increase in the maize yield (7.2 t·ha -1 ). In the case of drought there was a 4.0% yield loss in the N, NP and NK treatments compared to the same treatments in the dry years. This loss was only 1.0% in the NPK treatment. In very wet years the positive effects of a favourable water supply could be seen even in the N, NP and NK treatments (with yields of around 7.4 t·ha -1 ). The yield increment in these treatments compared with the droughty years averaged 8%, while balanced NPK fertilization led to a further 2% increase (10%). Significant quadratic correlations were found between the rainfall quantity during the vegetation period and the yield, depending on the nutrient supplies (Ø: R = 0.7787***, N: R = 0.8997***, NP: R = 0.9338***, NK: R = 0.9574***, NPK: R = 0.8906***). The optimum rainfall quantity and the corresponding grain yield ranged from 328-349 mm and 5.0-7.7 t·ha -1 , respectively, depending on the fertilizer rate. The grain yield increment obtained per mm rainfall in the case of optimum rainfall supplies was found to be 14.3-23.2 kg·ha -1 , while the quantity of rainfall utilized during the vegetation period for the production of 1 kg air-dry matter in the case of maximum yield amounted to 698, 449, 480, 466 and 431 litres in the control, N, NP, NK and NPK treatments, respectively. It was clear from the 43-year meteorological database for the experimental station (1961-2003) that over the last 23 years (1981-2003) the weather has become substantially drier. Compared with the data for the previous 20 years (1961-1980) there was an increase of 20, 500 and 50% in the number of average, dry and droughty years, no change in the number of wet years and a 71% drop in the number of very wet years.

Field experiments on the effect of applying a nitrogenous fertilizer to wheat at different stages of growth

1939 ◽  
Vol 29 (3) ◽  
pp. 379-398 ◽  
Author(s):  
D. J. Watson
Keyword(s):  
Grain Yield ◽  
Opposite Direction ◽  
Field Experiments ◽  
Shoot Height ◽  
Straw Yield ◽  
Time Of Application ◽  
Stages Of Growth ◽  
Nitrogenous Fertilizer ◽  
Short Period

An account is given of the results of two series of field experiments carried out at Rothamsted and Woburn in the years 1926 to 1936 on the effect of nitrogenous fertilizers on wheat. In the first series a comparison was made of the effects of early (March) and late (May) top-dressings, and in the second series a range of times of application from sowing to the end of May were tested.At Rothamsted, the increases of yield of grain produced by the nitrogenous fertilizer were small and rarely significant, but they were greater at Woburn. On the average of all experiments, the effect of the fertilizer on yield of grain was independent of the time of application. In individual years, variation in effectiveness between times of application was found, and this was correlated with the amount of rain falling in a short period after the time of application. At Woburn, the effectiveness of the fertilizer decreased with increase in the amount of rain falling immediately after the application of the fertilizer, but at Rothamsted the effects were less clear and appeared to be in the opposite direction.The effects on straw yield were relatively greater, and more consistent, than those on grain yield. A greater increase of straw yield was produced by early top-dressing (January–March) than by application at the time of sowing, and the increase declined steadily the later the time of topdressing. Shoot height was increased by the nitrogenous fertilizer, and varied with time of application in a similar manner to straw yield.

Effect of fertiliser phosphorus and nitrogen on the concentrations of oil and protein in grain and the grain yield of canola (Brassica napus L.) grown in south-western Australia

2007 ◽  
Vol 47 (8) ◽  
pp. 984 ◽  
Author(s):  
R. F. Brennan ◽  
M. D. A. Bolland
Keyword(s):  
Brassica Napus ◽  
Grain Yield ◽  
Western Australia ◽  
Field Experiments ◽  
Grain Production ◽  
Brassica Napus L ◽  
Single Superphosphate ◽  
P Deficiency ◽  
Soil P ◽  
Soil P Testing

The effect of fertiliser phosphorus (P) and nitrogen (N) on seed (grain) yield and concentration of oil and protein in grain of canola (oil-seed rape; Brassica napus L.) was measured in two field experiments undertaken at eight sites from 1993–2005 in south-western Australia, on soils deficient in P and N. Six rates of P (0–40 kg P/ha as single superphosphate) and four rates of N (0–138 kg N/ha as urea) were applied. Significant grain yield increases (responses) to applied P occurred in both experiments and these responses increased as rates of applied N increased. For grain production, the P × N interaction was significant in all eight years and locations of the two experiments. Application of P had no effect on concentration of oil and protein in grain. Application of N always decreased the concentration of oil and increased the concentration of protein in grain. For canola grain production in the region, responses to applied N always occur whereas responses to applied P are rare, but if soil P testing indicates likely P deficiency, both P and N fertiliser need to be applied.

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