Soil and weather conditions associated with plant damage from post-emergent metribuzin in lentil (Lens culinaris) in southern Australia

2019 ◽  
Vol 70 (11) ◽  
pp. 958
Author(s):  
Larn S. McMurray ◽  
Christopher Preston ◽  
Albert Vandenberg ◽  
Dili Mao ◽  
Jeffrey G. Paull

Multiple field experiments and a controlled-environment temperature study were conducted to investigate soil and weather conditions responsible for herbicide phytotoxicity in lentil (Lens culinaris Medik.) from post-emergent application of metribuzin. A linear relationship was observed between plant injury (% necrosis) and metribuzin rate in all 12 environments, but in only 11 environments for anthesis dry weight and nine environments for both plant density and grain yield. Grain-yield reduction from label metribuzin rates of 135 g a.i. ha–1 for sand and 285 g a.i. ha–1 for clay ranged from 0% to 32% and 0% to 67%, respectively, across all environments. Principal component analysis of soil and weather factors around the time of herbicide application suggested that metribuzin-induced plant damage in lentil was due to a combination of multiple soil and weather factors. However, heavy rainfall within 10 days of herbicide application, particularly on light-textured soils or where soil moisture was low, was most strongly linked to plant damage. Experiments targeting the impact of reductions in temperature post-metribuzin application showed no effect, and of light intensities pre- and post-metribuzin application showed low effects on plant-damage measures. Because rainfall in the 10 days after application is a major determinant of metribuzin damage in winter-grown lentil in southern Australia, a higher level of selective tolerance to metribuzin than that present in commercial cultivars is needed for its safe post-emergent use. Early and late measures of plant damage will be required to assess accurately plant tolerance to post-emergent metribuzin application in lentil.

2010 ◽  
Vol 46 (No. 1) ◽  
pp. 21-26 ◽  
Author(s):  
V. Šíp ◽  
J. Chrpová ◽  
O. Veškrna ◽  
L. Bobková

Reactions to artificial infection with Fusarium graminearum isolates and a new fungicide Swing Top were studied in nine winter wheat cultivars evaluated in field experiments at two sites for three years for expression of symptoms, deoxynivalenol (DON) content in grain and grain yield. The results demonstrate a pronounced and relatively stable effect of cultivar resistance on reducing head blight, grain yield losses and contamination of grain by the mycotoxin DON. It is advantageous that the moderate level of resistance to Fusarium head blight (FHB) was detected also in two commonly grown Czech cultivars Sakura and Simila. Average fungicide efficacy for DON was 49.5% and 63.9% for a reduction in yield loss, however, it was found highly variable in different years and sites. The joint effect of cultivar resistance and fungicide treatment was 86.5% for DON and even 95.4% for reducing the yield loss. A very high risk was documented for susceptible cultivars and also the effects of medium responsive cultivars were found to be highly variable in different environments and therefore not guaranteeing sufficient protection against FHB under different conditions.


Soil Research ◽  
2017 ◽  
Vol 55 (4) ◽  
pp. 341 ◽  
Author(s):  
Craig A. Scanlan ◽  
Ross F. Brennan ◽  
Mario F. D'Antuono ◽  
Gavin A. Sarre

Interactions between soil pH and phosphorus (P) for plant growth have been widely reported; however, most studies have been based on pasture species, and the agronomic importance of this interaction for acid-tolerant wheat in soils with near-sufficient levels of fertility is unclear. We conducted field experiments with wheat at two sites with acid soils where lime treatments that had been applied in the 6 years preceding the experiments caused significant changes to soil pH, extractable aluminium (Al), soil nutrients and exchangeable cations. Soil pH(CaCl2) at 0–10cm was 4.7 without lime and 6.2 with lime at Merredin, and 4.7 without lime and 6.5 with lime at Wongan Hills. A significant lime×P interaction (P<0.05) for grain yield was observed at both sites. At Merredin, this interaction was negative, i.e. the combined effect of soil pH and P was less than their additive effect; the difference between the dose–response curves without lime and with lime was greatest at 0kgPha–1 and the curves converged at 32kgPha–1. At Wongan Hills, the interaction was positive (combined effect greater than the additive effect), and lime application reduced grain yield. The lime×P interactions observed are agronomically important because different fertiliser P levels were required to maximise grain yield. A lime-induced reduction in Al phytotoxicity was the dominant mechanism for this interaction at Merredin. The negative grain yield response to lime at Wongan Hills was attributed to a combination of marginal soil potassium (K) supply and lime-induced reduction in soil K availability.


Weed Science ◽  
1995 ◽  
Vol 43 (2) ◽  
pp. 215-218 ◽  
Author(s):  
Mark J. Vangessel ◽  
Edward E. Schweizer ◽  
Karen A. Garrett ◽  
Philip Westra

The impact of weed density and weed distribution on irrigated corn yield was investigated in Colorado. Weed densities examined were 0,33,50, or 100% of the indigenous weed population. A series of weed distribution treatments were achieved by varying the length of the weed-free and weedy zones within the corn row while maintaining a constant weed population of 33 or 50% of the indigenous weed level. Grain yield was affected by weed density, but not by weed distribution. Each additional weed reduced corn yield 8.5 and 2.3 kg ha−1in 1991 and 1992, respectively. When corn yields were estimated with a computer weed/corn management model, weed densities 5 to 8 wk after planting provided a better yield reduction estimate than weed densities immediately before harvest.


Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 404
Author(s):  
Renata Gaj ◽  
Piotr Szulc ◽  
Idzi Siatkowski ◽  
Hubert Waligóra

A strict field experiment with maize was carried out in the years 2009–2011 at the Experimental Station of the Poznań University of Life Sciences. The impact of mineral fertilization levels on the nutritional status of plants at an early development stage 5–6 leaves (BBCH 15/16) was assessed, as well as the possibility of using biomass and the current state of nutrient supply to predict grain yield. The adopted assumptions were verified on the basis of field experiments with nine variants of mineral fertilization and two maize varieties (EURALIS Semences, Lescar, France) (ES Palazzo and ES Paroli SG—“stay-green” (SG)). Regardless of the variety tested, the plants were under-nutritioned with calcium and magnesium. Plant nutritional status and the accumulation of minerals at the BBCH 15/16 stage were the main factors determining the variability of maize grain yields. In addition, it was shown that maize biomass in the BBCH 15/16 stage, calcium content and the N:K ratio significantly determined grain yield of traditional variety. The yield of the “stay-green” hybrid was largely shaped by plant biomass in the BBCH 15/16 stage, potassium, calcium, magnesium contents and N:Mg ratio. Regression analysis showed that grain yield of the tested maize varieties was determined by plant biomass and its content from 59% to 69%.


Plant Disease ◽  
2017 ◽  
Vol 101 (9) ◽  
pp. 1621-1626 ◽  
Author(s):  
F. Workneh ◽  
S. O’Shaughnessy ◽  
S. Evett ◽  
C. M. Rush

Wheat streak mosaic (WSM) caused by Wheat streak mosaic virus, which is transmitted by the wheat curl mite (Aceria tosichella), is a major yield-limiting disease in the Texas High Plains. In addition to its impact on grain production, the disease reduces water-use efficiency by affecting root development. Because of the declining Ogallala Aquifer water level, water conservation has become one of the major pressing issues in the region. Thus, questions are often raised as to whether it is worthwhile to irrigate infected fields in light of the water conservation issues, associated energy costs, and current wheat prices. To address some of these questions, field experiments were conducted in 2013 and 2016 at two separate locations to determine whether grain yield could be predicted from disease severity levels, assessed early in the spring, for potential use as a decision tool for crop management, including irrigation. In both fields, disease severity assessments started in April, using a handheld hyperspectral radiometer with which reflectance measurements were taken weekly in multiple plots in arbitrarily selected locations across the fields. The relationship between WSM severity levels and grain yield for the different assessment dates were determined by fitting reflectance and yield values into the logistic regression function. The model predicted yield levels with r2 values ranging from 0.67 to 0.85 (P < 0.0001), indicating that the impact of WSM on grain yield could be fairly well predicted from early assessments of WSM severity levels. As the disease is normally progressive over time, this type of information will be useful for making management decisions of whether to continue irrigating infected fields, especially if combined with an economic threshold for WSM severity levels.


2012 ◽  
Vol 26 (2) ◽  
pp. 284-288 ◽  
Author(s):  
Samuel G. L. Kleemann ◽  
Gurjeet S. Gill

Two field experiments were undertaken at Roseworthy, South Australia from 2006 to 2007 to evaluate the performance of herbicide application strategies for the control of herbicide-resistant rigid ryegrass in faba bean grown in wide rows (WR). The standard farmer practice of applying postsowing PRE (PSPE) simazine followed by POST clethodim to faba bean grown in WR provided consistent and high levels of rigid ryegrass control (≥ 96%) and caused a large reduction (P < 0.05) in spike production (≤ 20 spikes m−2) as compared with nontreated control (560 to 722 spikes m−2). Furthermore, this herbicide combination resulted in greatest yield benefits for WR faba bean (723 to 1,046 kg ha−1). Although PSPE propyzamide used in combination with shielded interrow applications of glyphosate or paraquat provided high levels of rigid ryegrass control (≥ 93%), these treatments were unable to reduce ryegrass spike density within the crop row (20 to 54 spikes m−2) to levels acceptable for continued cropping. Furthermore, a yield reduction (13 to 29%) was observed for faba bean in treatments with shielded application of nonselective herbicides and could be related to spray drift onto lower leaves. These findings highlight that shielded interrow spraying in WR faba bean could play an important role in the management of rigid ryegrass in southern Australia. However, timing of shielded interrow applications on weed control, crop safety, and issues concerning integration with more effective early-season control strategies require attention.


2013 ◽  
Vol 59 (No. 10) ◽  
pp. 472-477 ◽  
Author(s):  
B. Roitner-Schobesberger ◽  
Kaul H-P

Amaranth is a promising C4-crop. However, for a wider spread of the crop a better understanding of factors that are influencing yield formation is crucial for optimizing the plant phenotype and enhancing yield. The present study wanted to clarify the effects of assimilate sources and sinks on yield formation by artificially altering source or sink size. Field experiments were conducted in Eastern Austria during three years with three genotypes, applying source-sink manipulation treatments at mid flowering (control, 50% of inflorescence removed, 50% or 100% of leaves removed). At maturity we measured shoot, inflorescence and grain dry matter, thousand kernel mass and number of seeds per plant. An average grain yield level of about 3.5 t/ha dry matter on control plots indicated favorable growth conditions for amaranth in general. The removal of all leaves had a strong detrimental effect on all parameters, but severity of yield reduction due to defoliation differed between genotypes, ranging from &ndash;49% to &ndash;73%. Contrastingly, 50% flower reduction did not have any significant effects. Also with 50% defoliation no significant yield reduction was observed. We conclude that source strength of amaranth during flowering is more yield limiting than its sink capacity.


2013 ◽  
Vol 46 (3) ◽  
pp. 29-38
Author(s):  
S.H. Mosavifeyzabadi ◽  
F. Vazin ◽  
M. Hassanzadehdelouei

Abstract In hot and arid regions, drought stress is considered as one of the main reasons for yield reduction. To study the effect of drought stress, nitrogen and zinc spray on the yield and yield components of corn, an experiment was carried out during the crop seasons of 2010 and 2011 on Emam Khomeyni research Farm in Mahvellat as a split factorial within randomized complete block design with three replicates. The main plots with irrigation factor and three levels were considered: full irrigation, stopping irrigation at anthesis step and stopping irrigation at the seed filling stage. Subplots were considered with and without nitrogen and zinc spray. The drought stress reduced the grain yield in anthesis stage more than other stages. Drought stress effects significantly on stem and ear diameter, ear length, chlorophyll value, leaf area index, leaf relative water content, stem, ear and leaves dry weight, number grain in ear and row, number row in ear, unfilled seed percentage and thousand grains weight. Nitrogen increased the seed yield and yield component except thousand grains weight and the number of row in ear. Using Zn, as compared with control treatment, causes the increase of grain yield, thousand grains weight and number grain in ear 16.5, 9 and 5.5%, respectively. The results obtained from the present research showed that anthesis stage was most sensitive stage to drought stress. Also nitrogen and Zn could somewhat reduce the impact drought stress on corn.


Author(s):  
A. T. Ajibola ◽  
G. O. Kolawole

Aims: Field experiments were conducted to determine compatibility of sesame varieties for intercropping with maize. Study Design: The experiment was a randomized complete block design with three replications. Place and Duration of Study: Teaching and Research Farm, LAUTECH, Ogbomoso, southern guinea savanna area of Nigeria during the 2010 and 2011 cropping seasons. Methodology: The treatments included Sole maize (Oba Super 1 variety), five sole sesame varieties (E-8, O3l, O1m, O2 m, Exotic-Sudan) and their intercrops, making a total of eleven treatments.  Sole maize was planted at a spacing of 75 cm x 25 cm. For intercrops, maize was planted at a spacing of 100 cm x 25  cm and sesame seeds were planted at a spacing of 100 cm x 10 cm such that sesame row alternated maize row. Maize was planted first and sesame was introduced two weeks after. Results: Intercropping maize with sesame varieties significantly (P = 0.05) reduced number of pods and grain yield of sesame varieties in both years. However, variety O2m produced grain yield in the intercrop similar to the mono crop. Generally, Intercropping sesame with maize significantly reduced the grain yield of maize by 36% compared to the sole crop. Exotic-Sudan varieties caused the highest percentage yield reduction (52%). Sesame varieties O2m and O3l were the only varieties whose yield advantage in intercropping with maize had land equivalent ratio (LER) of 1.28 and 1.18 while other varieties had values less than 1 indicating yield advantage of O2m and O3l with maize. The relative crowding coefficient (K) value of maize (4.98) was higher than sesame (0.44) thus indicating its dominance in the mixture. Conclusion: It is concluded that the prospective sesame farmers could grow varieties O2m and O3l in place of the popular E-8 because intercropping with maize did not affect their performances in both years.


2014 ◽  
Vol 47 (1) ◽  
pp. 39-47 ◽  
Author(s):  
K. Zare ◽  
F. Vazin ◽  
M. Hassanzadehdelouei

ABSTRACT In hot and arid regions, drought stress is considered as one of the main reasons for yield reduction. To study the effect of drought stress, Iron and potassium spray on the yield and yield components of corn, an experiment was carried out during the crop seasons of 2010 and 2011 on Abosaeid research field of Mahvellat as a split factorial within randomized complete block design with three replicates. The main plots with irrigation factor and three levels were considered: irrigation per 6, 9 and 12 days. Subplots were considered with and without Iron and potassium spray. The irrigation reduced the grain yield in irrigation per 12 more than other stages. Irrigation effects significantly on chlorophyll value, leaf relative water content, stem, ear and leaves dry weight, number grain in ear and row, number row in ear, unfilled seed percentage and thousand grains weight. Iron increased the seed yield and yield component, except unfilled seed percentage and SPAD. Using K, as compared with control treatment, causes the increase of grain yield, 1000 grains weight and number grain in ear 16.5, 9 and 5.5% respectively. Potassium could somewhat reduce the impact drought stress on corn.


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