Wheat yield response to rainfall in a long-term multi-rotation experiment in the Victorian Wimmera

1995 ◽  
Vol 35 (7) ◽  
pp. 951 ◽  
Author(s):  
MC Hannah ◽  
GJ O'Leary

Seventy-six years of wheat yield data from a long-term rotation experiment at Dooen in the Victorian Wimmera were analysed to describe the response of wheat yield to seasonal rainfall, crop sequence, and time. Wheat yields from 7 different 1- to 4-course rotations involving wheat, barley, oat, field pea, grass pasture and fallow were compared as a function of growing-season (May-November) rainfall. The field layout had no within-year replication, but each phase of each rotation was represented once in each year. An approximate quadratic response of wheat yield to both current year and previous year May-November rainfall was observed for each rotation. Previous year May-November rainfall boosted wheat yields grown on fallow, but decreased the yield of wheat grown on field pea or wheat stubble. Highest wheat yields followed fallow preceded by pasture, high yields followed fallow preceded by a cereal, moderate yields followed field pea, and low yields occurred for continuous wheat. Long-term trends in wheat yields adjusted for rainfall depended on crop sequence and fluctuated more in the non-fallow, 3-course rotations. Over the 76 years, average yield declined in all rotations except the continuous wheat, which was always low, but there was evidence that yield of all continuous cropped rotations had increased during the last 2 decades.

1972 ◽  
Vol 23 (6) ◽  
pp. 935 ◽  
Author(s):  
BR Elliott ◽  
R Jardine

The wheat yield trends of six rotation systems were examined over the 29-year period 1940-1968. The multiple regression model used incorporated variables to minimize the effect of climatic fluctuations and trends. All the rotation systems examined showed positive, almost linear, yield increases over the first 19 years (1940-1958). Over the final 10 years (1959-1968) those systems including a pasture phase continued to show a linear yield increase; other three-course systems (fallow, wheat, stubble crop) showed a less than linear yield increase; while the two-course system (fallow, wheat) showed a 22% yield decline. Possible factors influencing the yield trends are briefly discussed.


1975 ◽  
Vol 15 (72) ◽  
pp. 93
Author(s):  
B Palmer ◽  
VF McClelland ◽  
R Jardine

The relationships between soil tests for 'plant available' phosphate and wheat yield response to applied superphosphate were examined and the extent to which these relationships were modified by other soil measurements was determined. Soil samples and wheat yield data were obtained from experiments conducted in the Victorian wheat belt. The sites were grouped into four relatively uniform classes using soil pH measurement and geographic location. The soil test values differed widely and were accountable for by the soil characteristics measured. However, the overall and within group yield responses to applied superphosphate could not be accounted for in terms of either the soil test value or the associated chemical measurements. By inference, yield response was clearly dependent on factors other than those determining the results of soil tests.


2010 ◽  
Vol 59 (1) ◽  
pp. 135-144 ◽  
Author(s):  
E. Bertáné Szabó ◽  
J. Loch ◽  
Gy. Zsigrai ◽  
L. Blaskó

The effects of regular NPK fertilization on the amounts of winter wheat yield and the amounts and proportion of different N forms (NO 3 -N, NH 4 -N, N org , N total ) of a Luvic Phaeosem soil determined in 0.01 M CaCl 2 were studied in the B1740 variant of the National Long-Term Fertilization Experiment at Karcag. According to the yield data, N and P fertilization increased winter wheat yield significantly. When applying the 200 kg N·ha -1 dose, P fertilization resulted in a more than 2 t·ha -1 yield increase, as compared to the treatments without P fertilization. K fertilization had no effect on the yield, similarly to preceding years. These findings may be adapted to fields of the Middle-Tisza Region with similar conditions to the trial site. The N forms of the soil determined in CaCl 2 reflected fertilization well. All of the fractions, but especially NO 3 -N and N total , increased significantly in response to N fertilization. Close relationships (r = 0.87–0.88) were found among the NO 3 -N and N total fractions and the N balance, which means that the amounts of NO 3 -N and N total are suitable for assessing both the N deficit and the N surplus. The strength of the correlation between the NH 4 -N content and N balance was moderate (r = 0.65). The N org fraction increased significantly as a function of N and P fertilization. These results can be explained with the yield increase. A significant correlation (r = 0.55) was found between the N org fraction and yield amounts. It can be established that organic residuals remaining on the site resulted in a significant increase in the N org content of soils. The gained results confirm that the N org fraction is suitable for the characterization of the readily mobilizable N reserves previously ignored in fertilization practice. On the basis of the presented results the CaCl 2 method is recommended for the precise estimation of nutrient requirements.


2005 ◽  
Vol 85 (1) ◽  
pp. 95-102 ◽  
Author(s):  
A. M. Johnston ◽  
H. R. Kutcher ◽  
K. L. Bailey

Rotations are constantly being adapted to current economic and management realities. As a result, the crop sequence used tends to depend more on the economic value of particular crop types, principally cereals, oilseeds and pulse crops in the Saskatchewan Parkland, than on the best management practices for optimizing crop productivity. A study was conducted from 1999 to 2001 at Melfort, SK, to assess the effects of growing barley, wheat, canola, flax, and field pea on their own and the other crop stubbles. When a crop was seeded on its own stubble, the poorest grain yield and quality were recorded, a difference that often was related to major pathogens affecting crop productivity. In the first 2 yr of this study, when near normal temperature and precipitation were recorded, little difference was observed in the average crop yield response when any of the crops were seeded on the other broadleaf and cereal stubbles considered in the study. The exception was flax, which performed poorer when seeded on canola than flax stubble, a reflection of the negative impact canola has on arbuscular mycorrhizae populations on subsequent flax in rotation. In 2001, a year with below-normal precipitation and above-average temperature, crops seeded into pea and flax stubble had yields that were 15–40% of the best stubble treatments. Under these drought conditions, field pea was the best crop choice for flax stubble, while wheat was the best choice for pea stubble. The results of this study indicate that for the Saskatchewan Parkland, the lowest risk crop sequence decision is to avoid seeding a crop in its own stubble. Key words: Malt barley (Hordeum vulgare L.), spring wheat (Triticum aestivum L.), canola (Brassica napus L.), flax (Linum usitatissimum L.), pea, (Pisum sativum L.), crop rotation, disease management


2009 ◽  
Vol 60 (9) ◽  
pp. 901 ◽  
Author(s):  
M. R. Anwar ◽  
G. J. O'Leary ◽  
M. A. Rab ◽  
P. D. Fisher ◽  
R. D. Armstrong

Spatial variability in grain yield across a paddock often indicates spatial variation in soil properties, especially in regions like the Victorian Mallee. We combined 2 years of field data and 119 years of simulation experiments (APSIM-Wheat and APSIM-Barley crop models) to simulate crop yield at various levels of N application in 4 different management zones to explore the robustness of the zones previously determined for an experimental site at Birchip. The crop models explained 96% and 67% of the observed variability in wheat and barley grain yields, with a root mean square error (RMSE) of 310 kg/ha and 230 kg/ha, respectively. The model produced consistent responses to the observed data from the field experiment in 2004 and 2005 where a high and stable yielding zone produced the highest dry matter as well as grain yield, while a low and variable zone recorded the lowest grain yield. However, from the long-term (119 years) simulation, the highest median wheat yield value was obtained on the low variable zone (2911 kg/ha) with high N fertiliser application, while the lowest was obtained on the high variable zone (851 kg/ha). Similarly, the highest barley yields (1880–3350 kg/ha) occurred on the low variable zone using the long-term simulation. In 10–20% of years the highest yield occurred in the high-yielding zones, with the variable and stable zones changing rank with interactive behaviour only under early-sown conditions. Our analyses highlight the problem of using a limited range of seasons of different weather conditions in agronomy to make strategic conclusions as the long-term simulation did not confirm the original yield zone determination. The challenge ahead is to predict in advance the seasons where application of N fertiliser will be beneficial.


1997 ◽  
Vol 33 (4) ◽  
pp. 469-475 ◽  
Author(s):  
M. SINGH ◽  
S. CHRISTIANSEN ◽  
B. K. CHAKRABORY

The introduction of appropriate crop rotations is known to be beneficial in many farming systems. One feature of rotations is that it takes a valuable length of time for the advantage of the rotation to take effect. In long-term rotation trials, the observations from the same plot over years are correlated; ignoring such correlations may affect the precision of the estimates of rotation effects. We examined five covariance structures between the plot errors over time to assess the effect of correlations on the standard errors of rotation means and rotation x cycle combination (interaction) means on wheat yields using eight years of data from six two-phase rotations with wheat. Based on wheat yield data from the four cycles of the rotations considered, the compound symmetry covariance structure (constant correlation) between plot errors arising over alternate years gave more efficient estimates of rotation means compared with the other four covariance structures.


2021 ◽  
Author(s):  
João Paulo Ascari ◽  
Jhonatan Paulo Barro ◽  
Flávio Martins Santana ◽  
José M.V. Pádua ◽  
João L. N. Maciel ◽  
...  

Wheat blast, caused by Pyricularia oryzae Triticum (PoT) lineage, is a major constraint to wheat production, mainly in the tropics of Brazil where severe epidemics are more frequent. We analyzed disease and wheat yield data from 42 uniform field trials conducted during nine years (2012 to 2020) in order to assess whether the percent control and yield response were influenced by fungicide type, region (tropical or subtropical), and year. Six treatments were selected, all evaluated in at least 19 trials. Two fungicides were applied as solo active ingredients: MANCozeb, and TEBUconazole, and four were premixes: AZOXistrobin + TEBU, TriFLoXistrobin + PROThioconazole, TFLX + TEBU, and PYRAclostrobin + EPOXiconazole. Percent control, calculated from back-transforming estimates by a meta-analysis network model fitted to the log of the means, ranged from 43% to 58%, with all but PYRA + EPOX showing efficacy greater than 52% on average, not differing among them. The variation in both efficacy and yield response were explained by region and all but TEBU performed better in the subtropics than in the tropics. Yield response from using three sequential sprays was around two times greater in the subtropics (319 to 532 kg/ha) than in the tropics (149 to 241.3 kg/ha). No significant decline in fungicide efficacy or yield response were observed in nine years of study for any of the fungicides. Our results reinforce the need to improve control by adopting an integrated management approach in the tropics given the poorer performance and lower profitability, especially for the premixes, than in the subtropics.


1995 ◽  
Vol 35 (7) ◽  
pp. 835 ◽  
Author(s):  
JA Kirkegaard

Trends in wheat yield responses to conservation cropping in Australia were analysed using data from 33 medium-term (3-5 year) and long-term (>5 year) agronomic experiments. The overall effect of tillage (direct drilled v. cultivated) was small in all regions (-0.18 to +0.06 t/ha), while stubble retention (stubble retained v. stubble burnt) reduced yield in all regions (-0.31 to -0.02 t/ha). There was large year-to-year variation in the yield response to both tillage and stubble retention at all sites, but no consistent relationship between yield variation and amount or pattern of seasonal rainfall based on monthly totals. There was also little evidence that the yield of direct-drilled and stubble-retained treatments increased relative to cultivated or stubble-burnt treatments with the duration of the experiments, despite the improvement in soil conditions reported at many sites. The factors thought responsible for the year-toyear variation in yield response varied within and between regions, although some consistent effects emerged. Reduced early seedling growth of directdrilled crops was considered a major factor underlying the yield response at most sites, and this was rarely associated with the availability of water or nitrogen. High soil strength and increased severity of rhizoctonia root rot were responsible for these effects at some sites, but at others the cause remains unclear. Stubble retention influenced yield in many ways but the significance of the allelopathic effects of stubble, suspected by many authors to influence crop growth, is poorly understood. Adoption of direct drilling and stubble retention is likely to remain low in areas where no long-term yield benefit can be demonstrated and where greater management flexibility is offered by systems of reduced cultivation and late stubble burning-incorporation. Further research should identify and develop strategies to overcome the constraints to yield in conservation farming systems, particularly stubble retention, and assess the sustainability of recent innovations incorporating minimum disturbance and partial stubble retention. The more rapid adoption of such intermediate strategies will hasten the move of the grains industry toward sustainable production.


Plant Disease ◽  
2021 ◽  
Author(s):  
João Paulo Paulo Ascari ◽  
Jhonatan Barro ◽  
Flávio Martins Santana ◽  
Jose Maria Villela Padua ◽  
Joao Maciel ◽  
...  

Wheat blast, caused by Pyricularia oryzae Triticum (PoT) lineage, is a major constraint to wheat production, mainly in the tropics of Brazil where severe epidemics are more frequent. We analyzed disease and wheat yield data from 42 uniform field trials conducted during nine years (2012 to 2020) in order to assess whether the percent control and yield response were influenced by fungicide type, region (tropical or subtropical), and year. Six treatments were selected, all evaluated in at least 19 trials. Two fungicides were applied as solo active ingredients: MANCozeb, and TEBUconazole, and four were premixes: AZOXystrobin + TEBU, TriFLoXystrobin + PROThioconazole, TFLX + TEBU, and PYRAclostrobin + EPOXiconazole. Percent control, calculated from back-transforming estimates by a meta-analysis network model fitted to the log of the means, ranged from 43% to 58%, with all but PYRA + EPOX showing efficacy greater than 52% on average, not differing among them. The variation in both efficacy and yield response was explained by region and all but TEBU performed better in the subtropics than in the tropics. Yield response from using three sequential sprays was around two times greater in the subtropics (319 to 532 kg/ha) than in the tropics (149 to 241.3 kg/ha). No significant decline in fungicide efficacy or yield response was observed in nine years of study for any of the fungicides. Our results reinforce the need to improve control by adopting an integrated management approach in the tropics given the poorer performance and lower profitability, especially for the premixes, than in the subtropics.


1990 ◽  
Vol 70 (4) ◽  
pp. 1023-1032 ◽  
Author(s):  
A. T. WRIGHT

A study comparing the crop sequences pulse-barley-wheat and barley-barley-wheat, was conducted from 1982 to 1987 on Black and Gray-wooded soils in northeastern Saskatchewan. Faba bean (Vicia faba L.), field pea (Pisum sativum L.), and lentil (Lens culinaris Medic.) had similar effects, increasing subsequent cereal yield, on average, by 21% in the first and 12% in the second year. Incorporation of pulse residue was not necessary in order to attain high yields. The yield response of barley (Hordeum vulgare L.) to N fertilizer was slightly greater on barley than on pulse residue, but N fertilizer alone was unable to bring the yield on barley residue up to the yield on pulse residue. However, there were great differences in the effect of year, soil type, preceding crop, residue incorporation, and fertilizer response, and there were many significant interactions of these treatments. These treatment effects could not be consistently accounted for by differences in N cycling, soil moisture, or disease.Key words: Barley, faba bean, field pea, lentil, wheat, crop sequence


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