The effects of time of weed removal on growth and yield of sugar beet

1979 ◽  
Vol 93 (3) ◽  
pp. 693-709 ◽  
Author(s):  
R. K. Scott ◽  
S. J. Wilcockson ◽  
F. R. Moisey

SUMMARYField experiments at Sutton Bonington between 1970 and 1974 tested how crop yields were affected by hand weeding at different stages in the life of early- and latesown crops. Losses where weeds were never controlled ranged from 95% where tallgrowingChenopodium albumL. predominated to 50% whenStellaria media(L.) Vill. andTripleurospermum maritimumL.) Koch ssp.inodorumHyl ex. Vaarama (T.inodorum) were most involved.In five of the seven crops examined the latest date (X) at which weeding had to commence to prevent irreversible effects on growth and yield and the earliest date at which weeding could cease without yield loss (Y) coincided. For late March/early April sowings this occurred 6 weeks after crop emergence, while for late April/early May sowings in which events were more rapid the same stage was reached 4 weeks after emergence. For an early-sown crop in 1973, when rainfall was frequent and heavy andC. albumprolific, X preceded Y with an interval of 4 weeks between the two dates (4–8 weeks after crop emergence, mid-May to mid-June). In complete contrast for a late-sown crop in 1974, when the weather was exceptionally dry andC. albumvirtually absent, Y preceded X and a single weeding at any time between 2 and 8 weeks after emergence would have prevented yield loss.Sugar beet had generally reached the late singling stage (4–6 true leaves) by the time weeding must have commenced. During the next 6 weeks, final yield was depressed by 120–150kg/ha (1·;5%) with each day that weeds were allowed to remain. However, leaf production continued throughout the season and the crop was capable of recovering from early checks caused by weed competition. It proved possible for crops whose weights were depressed by 25–30% when first weeded to recover completely by harvest.

2017 ◽  
Vol 53 (No. 3) ◽  
pp. 187-193 ◽  
Author(s):  
Kunz Christoph ◽  
Sturm Dominic J ◽  
Sökefeld Markus ◽  
Gerhards Roland

Field experiments were conducted at two locations in 2014–2015 and 2015–2016 to investigate the weed suppressive ability of cover crop mulches in sugar beets. Three cover crops and two cover crop mixtures were tested in all four experiments. Weed densities ranged from 2 up to 210 plants/m<sup>2</sup> in Chenopodium album L. and Stellaria media (L.) Vill. as predominant species. Sinapis alba grew significantly faster than Vicia sativa, Raphanus sativus var. niger, and both cover crop mixtures. Sinapis alba, Vicia sativa, Raphanus sativus var. niger reduced weed density by 57, 22, and 15% across all locations, respectively. A mixture of seven different cover crops reduced weed emergence by 64% compared to the control plot without cover crop mulch. Early sugar beet growth was enhanced by all mulch treatments in 2015 and decelerated in 2016.


1990 ◽  
Vol 70 (4) ◽  
pp. 1215-1221 ◽  
Author(s):  
IRIS BITTERLICH ◽  
MAHESH K. UPADHYAYA

Field experiments were conducted in 1987 and 1988 to study the effect of lamb’s-quarters (Chenopodium album L.) interference on broccoli (Brassica oleracea L. var. botrytis ’Emperor’) growth and yield. Broccoli growth was initially affected by weed interference at 28–36 d after seeding. Generally, the negative effect of weed interference on broccoli growth increased with increasing weed density and time after seeding. Interference by 15 lamb’s-quarters plants m−2 reduced the biomass of broccoli plants by 71–73% compared to the weed-free control at 57–58 d after seeding. Weed density-crop yield relationship curves showed that one lamb’s-quarters plant m−2 decreased total yield by 18–20% and marketable yield by 22–37%. Lamb’s-quarters reduced the total yield per plot by decreasing the average head weight of broccoli. The number of heads per plot was not affected. Weed interference also reduced the weight of heads classified as marketable (> 10 cm across). However, in 1987 more heads failed to reach a marketable size which resulted in a much smaller marketable yield than in 1988.Key words: Brassica oleracea var. botrytis, broccoli, Chenopodium album L., weed density, weed interference, cole crop


1974 ◽  
Vol 83 (1) ◽  
pp. 125-133 ◽  
Author(s):  
P. C. Longden ◽  
R. K. Scott ◽  
D. W. Wood

SUMMARYFrom monogerm sugar-beet seed as harvested non-viable fruits have to be eliminated, multigerm ones rejected and the size made sufficiently uniform for use in precision drills. Seed which had been gently rubbed to remove some of the cortex was graded for diameter, thickness and by aspiration, either singly or in combination. Effects of grading were determined by laboratory germination tests, radiography and field sowings in which seedling emergence and crop growth and yield were recorded.Grading by thickness was effective in removing multigerm fruits. Grading by aspiration and diameter rejected non-viable seed and reduced the variation in size. By combining all three grading methods, samples of seed of 80% germination and 90% monogermity were produced, provided the seed lot as threshed gave at least 50% germination. True seed weight increased with fruit diameter but only the first aspiration was effective in removing light true seeds. Radiography showed that both aspiration and, to a less extent, grading by diameter were effective in removing most empty fruits but neither eliminated those with shrivelled seed. The field experiments confirmed that increase in fruit diameter or aspiration gave more seedlings. Even at uniform, high plant density, sugar yields were less from the smallest (less than 3 mm diameter) than from the other grades of seed. The initial aspiration also improved sugar yield but further aspiration decreased yield.


Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 515-520 ◽  
Author(s):  
H. M. Booker ◽  
P. Umaharan ◽  
C. R. McDavid

Field experiments were carried out in St. Augustine, Trinidad & Tobago, West Indies to determine the effects of time of inoculation of Cowpea severe mosaic virus (CPSMV) and cultivar on crop growth and yield in cowpea (Vigna unguiculata). Crop growth and yield loss were investigated through growth analysis and yield component analysis on three cultivars in two seasons (wet and dry). Time of inoculation had the most profound impact on yield. Inoculations during the early log phase (seedling stage), 12 days after seeding (DAS), consistently had the greatest impact (50 to 85% yield loss) compared with those inoculated during the exponential growth phase (24 DAS; 22 to 66% yield loss) or linear growth phase (35 DAS; 2 to 36% yield loss). The effects were particularly pronounced in the dry season and in the more determinate cultivar, H8-8-27. Reduction in maximum leaf area index, leaf area duration, or maximum vegetative dry matter explained reductions in yield. Yield reductions resulted primarily from reduced pod number per plant and, to a lesser extent, from reduced average pod dry weight. The results show that CPSMV control measures should be aimed at delaying infection by CPSMV to minimize the impact on cowpea yield.


2009 ◽  
Vol 23 (4) ◽  
pp. 503-506 ◽  
Author(s):  
John D. Everitt ◽  
J. Wayne Keeling

Field experiments were conducted in Hale Co., TX, in 2005 and 2006 to determine the effects of 2,4-D amine and dicamba applied at varying rates and growth stages on cotton growth and yield, and to correlate cotton injury levels and lint yield reductions. Dicamba or 2,4-D amine was applied at four growth stages including cotyledon to two-leaf, four- to five-leaf, pinhead square, and early bloom. Dicamba and 2,4-D amine were applied at 1/2, 1/20, 1/200, and 1/2000 of the recommended use rate. Crop injury was recorded at 14 days after treatments and late-season, and cotton lint yields were determined. Across all growth stages, 2,4-D caused more crop injury and yield loss than dicamba. Cotton lint was reduced more by later applications (especially pinhead square) and injury underestimated yield loss with 2,4-D. Visual estimates of injury overestimated yield loss when 2,4-D or dicamba was applied early (cotyledon to two leaf) and was not a good predictor of yield loss.


1995 ◽  
Vol 9 (1) ◽  
pp. 91-98 ◽  
Author(s):  
K. Neil Harker ◽  
Robert E. Blackshaw ◽  
Ken J. Kirkland

Field experiments were conducted from 1986 to 1988 at Lacombe and Lethbridge, Alberta and Scott, Saskatchewan to determine growth and yield response of canola to mixtures of ethametsulfuron with specific grass herbicides. Ethametsulfuron did not usually cause canola injury when mixed with sethoxydim. However, ethametsulfuron mixtures with the following grass herbicides listed in decreasing order of injury potential, often caused canola injury and yield loss: haloxyfop > fluazifop > fluazifop-P > quizalofop > quizalofop-P. Canola yield losses were severe in some experiments, ranging from 59% with quizalofop mixtures to 97% with haloxyfop mixtures; in other experiments, the same mixtures did not cause significant yield losses. ‘Tobin,’ aBrassica rapacultivar, tended to be more susceptible to injury than theB. napuscultivars ‘Pivot’ and ‘Westar.’ Canola injury symptoms were consistent with those expected from sulfonylurea herbicides. Therefore, we suggest that specific grass herbicides differentially impair the ability of canola to metabolize ethametsulfuron to inactive forms.


2018 ◽  
Vol 32 (4) ◽  
pp. 431-438 ◽  
Author(s):  
Xiao Li ◽  
Timothy Grey ◽  
William Vencill ◽  
James Freeman ◽  
Katilyn Price ◽  
...  

AbstractFomesafen provides effective control of glyphosate-resistant Palmer amaranth in cotton. However, cotton seedlings can be injured when fomesafen is applied PRE. Therefore, greenhouse and field experiments were conducted at Athens, GA, and at six locations in Alabama and Georgia in 2013 and 2016 to evaluate cotton growth and yield response to fomesafen applied PRE at 70, 140, 280, 560, 1,120, or 2,240 g ai ha−1, and in combination with pendimethalin, diuron, acetochlor, and fluridone at 1×label rates. Greenhouse bioassays indicated that fomesafen reduced cotton height and dry weight with increasing rate in Cecil sandy loam and Tifton loamy sand but not in Greenville sandy clay loam––possibly as a result of this soil’s higher organic matter (OM) and clay content. Fomesafen applied at 2,240 g ai ha−1 reduced cotton stand by as much as 83% compared to the nontreated check (NTC) at all field locations except Alabama’s Macon and Baldwin counties, and 1,120 g ai ha−1 reduced cotton stand only at Pulaski County, GA, by 52%. Cotton height was reduced by the two highest rates of fomesafen at all locations except Clarke County, GA, and Baldwin County, AL. Injury data indicated more visual injury followed increasing fomesafen rates, and high-rate treatments produced more injury in sandier soils. Cotton yield was unaffected by herbicide treatments at any location, except for the 1,120 g ai ha−1 rate at Pulaski County (49% yield loss compared to NTC), 2,240 g ai ha−1 at Pulaski County (72% yield loss), and Tift County (29% yield loss). These data indicated cotton yield should not be negatively affected by fomesafen applied PRE alone within label rates or in combination with pendimethalin, diuron, acetochlor, and fluridone at 1×label rates, although some visual injury, or stand or height reduction may occur early in the growing season.


1990 ◽  
Vol 70 (4) ◽  
pp. 1115-1122 ◽  
Author(s):  
LYLE FRIESEN ◽  
IAN N. MORRISON ◽  
GEORGE MARSHALL ◽  
WESLEY ROTHER

Field experiments were conducted in 1982 and 1983 to determine the effects of increasing densities (0–70 plants m−2) of volunteer wheat (Triticum aestivum L. Neepawa) and barley (Hordeum vulgare L. Bonanza) on the growth and seed yield of flax (Linum usitatissimum L. Dufferin). Rectangular hyperbolic models were fitted to data using nonlinear regression analysis. Results indicated that both volunteer cereals severely reduced flax biomass and yield, with volunteer barley interference causing greater losses than volunteer wheat at equivalent densities. From the regression equations it was calculated that an intermediate density of 30 volunteer wheat plants m−2 reduced the yield of flax by 49% in 1982 and 53% in 1983, whereas an equivalent density of volunteer barley plants reduced flax yields by 56% in 1982 and 67% in 1983.Key words: Competition, flax, volunteer wheat, volunteer barley, rectangular hyperbola, yield loss


2021 ◽  
Vol 45 (1) ◽  
Author(s):  
E. M. Abd El Lateef ◽  
B. B. Mekki ◽  
M. S. Abd El-Salam ◽  
I. M. El-Metwally

Abstract Background The objective of this work is to identify the most proper herbicidal treatment on sugar beet to compare different single weed control herbicide doses on sugar beet traits and associated weeds as well as yield and quality under sandy soil conditions. Therefore, two field experiments were conducted during the winter seasons of 2017/2018 and 2018/2019 at the Experimental Farm of the National Research Centre, El-Beheira Governorate. Tigro at 1.0 and 0.750 l fed−1, Betasana-Trio at 0.675 and at 0.9 l fed−1, Select Super at 0.5 and 0.375 l fed−1 and Betanal MaxxPro at 0.5 l fed−1 besides the unweeded and hand weeded twice were used. Results The results showed that the herbicides Betasana-Trio at 0.9 l fed−1, Tigro at 1.0 l fed−1 and Betasana-Trio at 0.675 l fed−1 when sprayed twice could effectively and/or completely eliminate the broadleaved weeds associated with sugar beet plants. Moreover, the results indicated and confirmed that Tigro and Betasana-Trio herbicides are effective in controlling broadleaved weeds. Similar tendency was recorded for the narrow-leaved weeds, where Select Super or Betanal MaxxPro at 0.5 l fed−1 as well as Select Super at 0.375 l fed−1 could completely eliminate or minimize the narrow-leaved weeds associated with sugar beet plants. The greatest significant root length, root diameters and root yield plant−1 were recorded when hand weeding twice followed by Betanal MaxxPro at 0.5 l fed−1 without significant differences. Gross sugar % ranged between 12.08 and 15 .7% and extractable sugar % ranged between 8.97 and 13.8% for Betasana-Trio at 0.09 l fed−1 and Betanal MaxxPro at 0.5 l fed−1. Conclusion Betanal MaxxPro gave the highest values of root and biological yield ton fed−1. Betanal MaxxPro followed by hand weeding treatment twice resulted in the greatest sugar yield fed−1. The highest sugar yield resulted from the herbicidal treatment with Betanal MaxxPro or Tigro at 1.0 l fed−1, which gave the greatest gross and extractable sugar yield fed−1 and exceeded the hand weeding treatment by 10.4 and 7.8%.


1974 ◽  
Vol 83 (3) ◽  
pp. 427-434 ◽  
Author(s):  
M. J. Durrant ◽  
A. P. Draycott ◽  
D. A. Boyd

SummaryThe results of 216 field experiments with sugar beet (1957–69), testing K and Na fertilizers, were re-examined. There were only small increases in yield with K or Na on peat or peaty mineral soils but on mineral soils, 100 kg K/ha without Na increased sugar yield by about 0·4 t/ha and 100 kg Na/ha without K increased yield by 0·6 t/ha. Although the average response per kg of nutrient was approximately in inverse proportion to their atomic weights, K and Na were only partially interchangeable; their relative effects differed from field to field and year to year.K seemed most effective in years with more than 80 mm rainfall in March–April but responses were halved when rainfall was 50 mm or less. Sowing date and the interval between giving fertilizer and sowing also influenced response to K; with late-sown crops, K fertilizer given within two weeks of sowing was usually ineffective. Response to Na differed much less with season so Na was on average more effective than K, especially in dry springs. It seems, therefore, that instances of near-perfect substitution between K and Na fertilizers result from chance combinations of weather and crop husbandry.Since in some experiments yields from a combined dressing exceeded those from either nutrient alone, and as the weather is largely unpredictable, both K and Na fertilizers should be given on all mineral soils, except those very rich in K, to be certain of avoiding yield loss. Texture and exchangeable soil K and Na also affected both the amount and rate of response, but did not much influence optimal fertilizer dressings and so are not very useful for making differential fertilizer recommendations.


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