Fall and Spring Applications of Trifluralin and Metribuzin in Fababeans (Vicia faba)

Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 691-695 ◽  
Author(s):  
M. F. Betts ◽  
I. N. Morrison

Field experiments were conducted to study the effect of fall and spring pre-plant incorporated applications of trifluralin (α,α,α-tri-fluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one] alone and in combinations on crop tolerance, seed yield, and weed control in fababeans (Vicia fabaL. ‘Diana’). Trifluralin applied either in the fall or the spring resulted in acceptable control of green foxtail [Setaria viridis(L.) Beauv.] and wild oat (Avena fatuaL.) while metribuzin resulted in excellent control of wild mustard [Brassica kaber(DC.) L.C. Wheeler var.pinnatifida(Stokes) L.C. Wheeler]. In 2 out of 3 yr, a tank-mixture of trifluralin plus metribuzin applied in the fall at 1.4 and 0.4 kg/ha, respectively, resulted in significantly larger seed yield than the same combination applied at 1.1 and 0.3 kg/ha in the spring. Although the fall treatments generally resulted in higher seed yields, there was no consistent difference in weed densities between fall and spring applications. In both field and growth room studies, trifluralin reduced the injury to fababeans from metribuzin. A postemergence application of metribuzin in the spring at 0.3 kg/ha following a fall-application of trifluralin resulted in good wild mustard control but caused considerable crop damage. Dinoseb (2-sec-butyl-4,6-dinitrophenol) and bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2dioxide] controlled wild mustard effectively with no injury to the crop.

1978 ◽  
Vol 90 (2) ◽  
pp. 261-267 ◽  
Author(s):  
P. D. Hebblethwaite ◽  
A. Burbidge ◽  
D. Wright

SummaryThe effects of lodging on the seed yield of S. 23 and S. 24 perennial ryegrass were investigated in a series of field experiments from 1973 to 1976. Natural lodging severely reduced seed yield in all years as a result of a decrease in the number of seeds per unit area. Controlled lodging at different stages of crop growth produced more variable results, indicating that lodging may affect both pollination and seed development. Disturbance of the crop during anthesis in order to aid pollination did not improve seed yields, possibly as a result of damage incurred.


1980 ◽  
Vol 60 (4) ◽  
pp. 1115-1121 ◽  
Author(s):  
M. F. BETTS ◽  
I. N. MORRISON

Fababean plants were swathed or desiccated with diquat [6,7-dihydrodipyrido (1,2-A:2′, 1′-C) pyrazinediium salt] at four stages of maturity corresponding to the time when 0, 10, 25 and 50% of the pods had turned from green to black. Over the 3 yr of the study no significant differences were observed between seed yields from swathed or desiccated plants. Regardless of whether the plants were swathed or desiccated, yields and seed quality tended to be higher from plants which had 25% or more black pods at the time of treatment. Desiccating before 25% of the pods have turned black may have a more serious effect on reducing seed quality than swathing before the recommended time. By desiccating prematurely, there is a risk of reducing seed quality by significantly increasing the number of discolored or shrivelled seeds.


1977 ◽  
Vol 88 (3) ◽  
pp. 605-614 ◽  
Author(s):  
P. D. Hebblethwaite

SUMMARYThe effects of irrigation and nitrogen on S. 23 perennial ryegrass grown for seed were investigated in a series of field experiments from 1972 to 1974. Irrigation significantly increased seed yield by 16% in 1972 and 52% in 1974 but had no effect in the wet year of 1973. In 1972 maximum deficit reached 110 mm at the end of July and coincided with anthesis. Consequently the yield response was due to an increase in number of seeds per unit area and no other seed yield component was affected. In 1974 peak deficit also reached about 100 mm but started to build up rapidly very early in the season and had reached 80 mm by the time that the first ears emerged. Consequently the yield response was due to increases in number of fertile tillers, number of seeds per unit area and 1000-seed weight.Irrigation had no significant effect on number of florets or seeds, except in 1974 when percentage of florets which produced seed was increased by 2%.Irrigation had some effect on threshed straw yields, total dry matter, harvest index and total number of tillers but where this occurred the response was much smaller than that of seed yield which indicates that irrigation had greater effects on the reproductive development of the crop than on yield of dry matter and tillering patterns. Increasing the quantity of nitrogen from 0 to 80 kg/ha increased seed yields, all seed yield components except 1000-seed weight, threshed straw yields and total dry matter and number of tillers at most sampling dates. Increasing the quantity of nitrogen from 80 to 160 kg/ha had little further effect on the above components except in 1972 where seed yields were significantly decreased.In 1972 number of florets was increased and percentage of florets which produced seed decreased with increasing quantities of nitrogen.


2019 ◽  
Vol 11 (10) ◽  
pp. 264
Author(s):  
Ana Paula Rockenbach ◽  
Mauro Antônio Rizzardi ◽  
Adriana Favaretto ◽  
Theodoro Schneider ◽  
Andréa Michel Sobottka

The objective of this study was to evaluate changes in soybean secondary metabolism and soybean yield components when subjected to coexistence periods with volunteer corn and established horseweed (Conyza spp.) regrowth. Two field experiments were conducted in the agricultural years 2015/2016 and 2016/2017 at Passo Fundo University, Passo Fundo, Rio Grande do Sul, Brazil. Experiment I was conducted in the agricultural year 2015/2016 in order to establish periods of coexistence between soybean and corn. The treatments consisted of two soybean densities in the main plots (175,000 and 350,000 plants ha-1) and different periods of coexistence between soybean and corn in the subplots. Experiment II was conducted in the agricultural year of 2016/2017 in order to investigate the interference of regrowth horseweed during coexistence periods with soybean. The total phenols, flavonoids, saponins, soybean yield components and seed yields were evaluated. Volunteer corn that initiates growth after the V4 soybean stage and horseweed regrowth during cultivation do not adversely affect secondary metabolism, seed yield or soybean yield components.


1998 ◽  
Vol 12 (4) ◽  
pp. 610-616 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Greg Semach ◽  
Toby Entz

Field experiments were conducted to identify herbicides for selectively controlling foxtail barley seedlings in spring wheat and flax. ICIA0604, fenoxaprop-P/safener, CGA184927/safener, metribuzin, and MON37500 in wheat and sethoxydim, clethodim, quizalofop, fluazifop-P, and the mixture of fluazifop-P/fenoxaprop-P in flax were applied at the three- to four-leaf and one- to three-tiller stages of foxtail barley. MON37500 was the only herbicide tested in wheat that provided excellent control of foxtail barley and a high degree of crop tolerance. MON37500 at 13 to 19 g/ha applied at the early growth stage controlled foxtail barley but rates of 25 to 30 g/ha were needed at the later growth stage. In flax, quizalofop was the most efficacious herbicide on foxtail barley. Sethoxydim and clethodim sometimes provided weed control similar to that of quizalofop when applied at the three- to four-leaf stage, but quizalofop was always more effective at the one- to three-tiller stage of foxtail barley. Wheat and flax yields were greater when effective herbicides were applied at the early than at the late stage, indicating the need for early control of foxtail barley to minimize weed competition. MON37500 in wheat and quizalofop in flax provide growers with highly efficacious herbicide options for in-crop control of foxtail barley in conservation tillage systems.


1992 ◽  
Vol 38 (6) ◽  
pp. 588-593 ◽  
Author(s):  
D. J. Hume ◽  
D. H. Blair

In the absence of Bradyrhizobium japonicum populations in the soil, yields of field-grown soybean (Glycine max (L.) Merrill) usually respond to inoculation with B. japonicum. The objective of this research was to determine the relationship between numbers of B. japonicum per seed in inoculants and soybean nodulation and yield. A total of six field experiments were conducted in 1989 and 1990 on new soybean soils. In dilution trials, Grip inoculant was applied to provide approximately 106, 105, 104, and 103B. japonicum per seed at two locations in 1989. Nodule number and mass, as well as seed yield, increased curvilinearly upward with increasing log10 most probable numbers (MPNs) of B. japonicum. The yield response curve was best fit by a cubic equation, which accounted for 97% of the variation in yield. Seed yields increased 19% (1.83 to 2.13 Mg/ha) from 105 to 106B. japonicum per seed. In field experiments involving 8 commercial inoculants in 1989 and 10 in 1990, and conducted at two locations in each year, responses to increasing log MPNs in the inoculants also were concave upwards and cubic. In the two years, 78 and 46% of the yield variation was accounted for by log MPN per seed. Increasing MPN per seed from 105 to 106 improved yields in first-time fields by an average of 24%, indicating the present minimum standard of 105B. japonicum per seed should be increased. Key words: most probable numbers, response to inoculation, nodulation, Glycine max (L.) Merrill.


1992 ◽  
Vol 72 (1) ◽  
pp. 203-207 ◽  
Author(s):  
R. E. Blackshaw ◽  
D. A. Derksen

Greenhouse and field studies were conducted to determine the tolerance of cultivated mustards, Brassica juncea and B. hirta to the herbicide DPX-A7881 [methyl 2-(4-ethoxy-6-menthylamino-1,3,5-triazin-2-yl) (amino) (carbonyl) (amino) (sulfonyl) benzoate]applied at various rates and stages of growth. Cultivated mustards are tolerant to DPX-A7881 at rates required to control wild mustard (Sinapis arvensis L.) thus fallowing the previously impossible selective control of this weed in cultivated mustards.Key words: Crop tolerance, growth stage, seed yield, DPX-A7881, Ethametsulfuron


Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 338-345 ◽  
Author(s):  
Jesper Rasmussen ◽  
Helle H. Nielsen ◽  
Hanne Gundersen

POST weed harrowing and other cultivation methods to control weeds in early crop growth stages may result in crop damage due to low selectivity between crop and weeds. Crop tolerance to cultivation plays an important role but it has not been clearly defined and analyzed. We introduce a procedure for analyzing crop tolerance on the basis of digital image analysis. Crop tolerance is defined as the ability of the crop to avoid yield loss from cultivation in the absence of weeds, and it has two components: resistance and recovery. Resistance is the ability of the crop to resist soil covering and recovery is the ability to recover from it. Soil covering is the percentage of the crop that has been buried because of cultivation. We analyzed data from six field experiments, four experiments with species of small grains, barley, oat, wheat, and triticale, and two experiments with barley cultivars with different abilities to suppress weeds. The order of species' tolerance to weed harrowing was triticale > wheat > barley > oat and the differences were mainly caused by different abilities to recover from soil covering. At 25% soil covering, grain yield loss in triticale was 0.5%, in wheat 2.5%, in barley 3.7%, and in oat 6.5%. Tolerance, resistance, and recovery, however, were influenced by year, especially for oat and barley. There was no evidence of differences between barley cultivars in terms of tolerance indicating that differences among species are more important than differences among cultivars. Selectivity analysis made it possible to calculate the crop yield loss due to crop damage associated with a certain percentage of weed control. In triticale, 80% weed control was associated with 22% crop soil cover on average, which reduced grain yield 0.4% on average in the absence of weeds. Corresponding values for wheat, barley, and oat were 23, 21, and 20% crop soil cover and 2.3, 3.6, and 5.1% grain yield loss.


1995 ◽  
Vol 35 (1) ◽  
pp. 97 ◽  
Author(s):  
H Marcellos ◽  
KJ Moore ◽  
A Nikandrow

The effects of 5 foliar-applied fungicides on seed yield of faba bean (Vicia faba) cv. Fiord were studied over 3 years at Tamworth in northern New South Wales. In 2 seasons when the diseases chocolate spot (Botrytis fabae) and rust (Uromyces viciae-fabae) were significant, 5 applications of foliar fungicides after flowering increased yield, by up to 1.6 t/ha in 1990 and nearly 0.9 t/ha in 1992, compared with the unsprayed treatment.Mancozeb, dichlofluanid, and tebuconazole were the most effective fungicides for preventing yield reduction, and vinclozolin and procymidone had little or no effect. Mancozeb and tebuconazole were effective in reducing the severity of both diseases, whereas procymidone was only active against chocolate spot. Differences between the most effective fungicides when applied 5 times or twice (at early and mid flowering) were seldom significant. Seed yields following 2 applications of tebuconazole were significantly higher than from 1 application, but for mancozeb, 2 applications were better than 1 in 1992 only. It was estimated that rust accounted for most of the yield loss in 1990 and 1992, and did so mainly by reducing seed size. Application of mancozeb early and during late flowering provided an effective and economical increase in grain yield in 1990 and 1992.


2003 ◽  
Vol 51 (4) ◽  
pp. 437-444 ◽  
Author(s):  
H. Z. Ghosheh ◽  
M. K. El-Shatnawi

Field experiments were conducted to evaluate the efficacy of herbicides applied alone or in combination for broadleaf weed control in chickpeas, faba beans and lentils. Herbicide applications of metribuzin pre-emergence; pendimethalin pre-emergence; bentazon post-emergence; metribuzin pre-emergence followed by bentazon post-emergence; and pendimethalin pre-emergence followed by bentazon post-emergence were examined and compared to weedy and hand-weeded plots. In chickpeas, metribuzin provided substantial control of broadleaf weeds; however, some injury was observed. Pre-emergence applications in faba beans provided substantial control of broadleaf weeds, and the bean yield was comparable to hand-weeded plots. No additional advantage was observed from combining bentazon with pre-emergence applications. Lentil plants were sensitive to herbicide applications, which caused crop injury and reduced the seed yield significantly.


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