Imidazolinone Herbicide Effects on Following Rotational Crops in Southern Alberta

1996 ◽  
Vol 10 (1) ◽  
pp. 100-106 ◽  
Author(s):  
James R. Moyer ◽  
Rudy Esau

The effect of imazethapyr and imazamethabenz on following crops was tested in southern Alberta, on Dark Brown and Brown Chernozemic soils, to assess the potential restrictions placed on cropping sequences by the use of these herbicides. Imazamethabenz reduced the yield of sugarbeet seeded one year after application. After imazethapyr application there is risk of yield loss with flax, corn, meadow bromegrass, mustard, sunflower, timothy, and wheat seeded one year later; canola seeded up to two years later; and sugarbeet and potato seeded up to three years later. Legume crops and intermediate wheatgrass may be seeded the year after application with little risk of yield loss. The required recropping intervals limit the use of imazethapyr for weed control in pea, alfalfa, or dry bean in cropping sequences that include sugarbeet, canola, or potato.

Weed Science ◽  
2013 ◽  
Vol 61 (3) ◽  
pp. 452-459 ◽  
Author(s):  
Alfonso S. Frenda ◽  
Paolo Ruisi ◽  
Sergio Saia ◽  
Benedetto Frangipane ◽  
Giuseppe Di Miceli ◽  
...  

Weeds are often the major biological constraint to growing legume crops successfully, and an understanding of the critical period of weed control (CPWC) is important for developing environmentally sustainable weed management practices to prevent unacceptable yield loss. Therefore, we carried out two field experiments to identify the CPWC for two grain legume crops traditionally grown in Mediterranean areas: chickpea and faba bean. The experiments were conducted at two sites both located in the Sicilian inland (Italy). In chickpea, when weeds were left to compete with the crop for the whole cycle, the grain yield reduction was on average about 85% of the weed-free yield, whereas in faba bean the reduction was less severe (on average about 60% of the weed-free yield). The onset of the CPWC at a 5% yield loss level varied by species, occurring later in faba bean than in chickpea (on average, 261 and 428 growing degree days after emergence for chickpea and faba bean, respectively). In both species, the end of the CPWC occurred at the early full-flowering stage when the canopy of each crop enclosed the interrow space. On the whole, the CPWC at a 5% yield loss level ranged from 50 to 69 d in chickpea and from 28 to 33 d in faba bean. The results highlight the fact that faba bean has a higher competitive ability against weeds than chickpea. This could be attributable both to more vigorous early growth and to the plant's greater height, both factors related to a greater shading ability and, consequently, to a better ability to suppress weeds.


Author(s):  
A.J. Cresswell

This paper, as well as being a testimonial to the benefit the writer has received from the Grassland Association, shows how the knowledge of scientists has been used to increase lucerne seed yields by methods of growing resistant cultivars especially for seed production as opposed to growing for hay, silage or grazing. It shows how new cultivars can be multiplied quickly by growing two crops in one year, one in each hemisphere, by using low seeding rates, wide plant spacing and very good weed control. Increased flowering of the crop has been achieved by the use of boron and the choice of time of closing; better pollination has been achieved by the use of more efficient bees - two varieties of which have been imported from North America. Weed and insect pest control and the use of a desiccant at harvest are contributing to a four-fold increase in seed yield, which should double again soon,


2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.


2006 ◽  
Vol 86 (3) ◽  
pp. 875-885 ◽  
Author(s):  
J. R. Moyer ◽  
S. N. Acharya

Weeds, especially dandelion (Taraxacum officinale Weber in F.H. Wigg.), tend to infest a forage alfalfa (Medicago sativa L.) stand 2 to 4 yr after establishment. To develop better weed management systems, experiments were conducted at Lethbridge, Alberta, from 1995 to 2002 and Creston, British Columbia, from 1998 to 2001, which included the alfalfa cultivars Beaver (standard type) and AC Blue J (Flemish type) and annual applications of metribuzin and hexazinone. These herbicides are registered for weed control in irrigated alfalfa in Alberta and alfalfa grown for seed. In addition, two sulfonylurea herbicides, metsulfuron and sulfosulfuron, and glyphosate were included. All of the herbicides except glyphosate controlled or suppressed dandelion and mustard family weeds. Metsulfuron at 5 g a.i. ha-1 almost completely controlled dandelion at both locations. However, after metsulfuron application at Lethbridge, dandelion was replaced with an infestation of downy brome, which is unpalatable for cattle. None of the herbicides increased total forage (alfalfa + weed) yield, and in some instances herbicides reduced forage quality by causing a shift from a palatable to an unpalatable weed species. However, it was observed that AC Blue J consistently yielded more than Beaver, and weed biomass was consistently less in the higher-yielding cultivar. AC Blue J was developed primarily for the irrigated area in southern Alberta and for southern British Columbia. Therefore, additional experiments should be conducted to determine which alfalfa cultivars have the greatest ability to compete with weeds in other regions of western Canada. Key words: Alfalfa yield, dandelion, forage quality, weed control


Weed Science ◽  
2015 ◽  
Vol 63 (1) ◽  
pp. 346-352 ◽  
Author(s):  
Nicholas E. Korres ◽  
Jason K. Norsworthy

Cover crops are becoming increasingly common in cotton as a result of glyphosate-resistant Palmer amaranth; hence, a field experiment was conducted in 2009 and 2010 in Marianna, AR, with a rye cover crop used to determine its effects on the critical period for weed control in cotton. Throughout most of the growing season, weed biomass in the presence of a rye cover crop was lesser than that in the absence of a rye cover crop. In 2009, in weeks 2 through 7 after planting, weed biomass was reduced at least twofold in the presence of a rye cover compared with the absence of rye. In 2009, in both presence and absence of a rye cover crop, weed removal needed to begin before weed biomass was 150 g m−2, or approximately 4 wk after planting, to prevent yield loss > 5%. Weed density was less in 2010 than in 2009, so weed removal was not required until 7 wk after planting, at which point weed biomass values were 175 and 385 g m−2in the presence and absence of a cover crop, respectively.


2015 ◽  
Vol 43 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Dogan ISIK ◽  
Adem AKCA ◽  
Emine KAYA ALTOP ◽  
Nihat TURSUN ◽  
Husrev MENNAN

Accurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used to assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.


2020 ◽  
Vol 34 (4) ◽  
pp. 624-629 ◽  
Author(s):  
J. Anita Dille ◽  
Phillip W. Stahlman ◽  
Curtis R. Thompson ◽  
Brent W. Bean ◽  
Nader Soltani ◽  
...  

AbstractPotential yield losses in grain sorghum due to weed interference based on quantitative data from the major grain sorghum-growing areas of the United States are reported by the WSSA Weed Loss Committee. Weed scientists and extension specialists who researched weed control in grain sorghum provided data on grain sorghum yield loss due to weed interference in their region. Data were requested from up to 10 individual experiments per calendar year over 10 yr between 2007 and 2016. Based on the summarized information, farmers in Arkansas, Kansas, Missouri, Nebraska, South Dakota, and Texas would potentially lose an average of 37%, 38%, 30%, 56%, 61%, and 60% of their grain sorghum yield with no weed control, and have a corresponding annual monetary loss of US $19 million, 302 million, 7 million, 32 million, 25 million, and 314 million, respectively. The overall average yield loss due to weed interference was estimated to be 47% for this grain sorghum-growing region. Thus, US farmers would lose approximately 5,700 million kg of grain sorghum valued at approximately US $953 million annually if weeds are not controlled. With each dollar invested in weed management (based on estimated weed control cost of US $100 ha−1), there would be a return of US $3.80, highlighting the return on investment in weed management and the importance of continued weed science research for sustaining high grain sorghum yield and profitability in the United States.


1996 ◽  
Vol 76 (4) ◽  
pp. 915-919 ◽  
Author(s):  
R. E. Blackshaw ◽  
G. Saindon

A field study was conducted during 3 yr to determine the growth and yield response of Pinto, Pink Red and Great Northern dry beans to various doses of imazethapyr. Imazethapyr was applied postemergence at 0, 25, 50 75 100, 150, and 200 g ha−1 to each class of dry bean. Results indicated that these four classes of dry beans responded similarly to imazethapyr. Dry bean injury increased and yields were reduced as dose of imazethapyr increased. At the proposed use dose of 50 g ha−1, imazethapyr reduced yield by 5 to 6%. Imazethapyr at 100 g ha−1 reduced dry bean yield by 10 to 12% and delayed maturity by 3 to 4 d. Benefits of superior weed control attained with imazethapyr should be weighed against potential crop injury when growers consider using imazethapyr in their dry bean weed management programs. Key words: Herbicide injury, maturity, seed yield, seed weight


1997 ◽  
Vol 11 (2) ◽  
pp. 257-264 ◽  
Author(s):  
Charlotte V. Eberlein ◽  
Paul E. Patterson ◽  
Mary J. Guttieri ◽  
Jeffrey C. Stark

A 3-year study was conducted in irrigated potato to compare weed control efficacy and economics of hilling plus one or two cultivations with the standard treatment of hilling plus a preemergence application of pendimethalin plus metribuzin. Trials were conducted under both weedy and weed-free conditions. Common lambsquarters and redroot pigweed were present in weedy treatments each year; significant populations of hairy nightshade and green foxtail also were present one year. When weed populations were low or moderate (< 45 plants/m2), total weed biomass in the hilling plus one cultivation treatment was reduced 98 to 99% relative to the weedy control, and U.S. No. 1 tuber yields were equal to the standard treatment. However, when weed populations were high (145 plants/m2), hilling plus one cultivation and hilling plus two cultivations provided only 30% and 61% reduction in weed biomass, respectively, and U.S. No. 1 tuber yields were 35% and 13% less, respectively, than the standard treatment. The standard treatment provided 99% reduction in total weed biomass each year, and yields were equal to the weed-free, hill plus no cultivation control. Net return was $37 to $100/ha higher for the hilling plus one cultivation treatment compared to the standard treatment when weed populations were moderate or low, but was $808/ha less than the standard treatment when weed populations were high.


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