scholarly journals Differential responses of two cowpea (Virgina unguiculata L.Walp.) genotypes to pre-emergence herbicides in the savannah woodland and rainforest agroclimatic regions of Sierra Leone

2021 ◽  
Vol 10 (1) ◽  
pp. 343-355
Author(s):  
Dan David. Quee ◽  
Philip Jimia. Kamanda ◽  
Musa Decius. Saffa ◽  
Johnny Ernest. Norman

Field trials were conducted in savannah woodland (Njala) and rainforest (Serabu) agroclimatic regions of Sierra Leone during 2016 second cropping season to assess different preemergence herbicides techniques that is efficient, cost effective and environmentally safe in cowpea production. The experiment consisted of 20 treatments which included 2 cowpea genotypes (slipea 4 and slipea 5) and 10 different weed control techniques viz: butachlor 50% emulsifiable concentrate (EC), double force®, power force® applied as preemergence herbicides at 2, 4 and 6 L ha-1, respectively and weedy check. The treatments were laid out in a strip-plot design arranged in a factorial system with three replications. The results of this study revealed that the application of power force® at 6 L ha-1 recorded the highest phytotoxic effect, lowest weed dry weight, number of pods per plant and grain yield, highest total variable cost, lowest gross and net returns. Furthermore, butachlor 50% EC at 2 L ha-1 closely followed by double force® at 6 L ha-1 resulted in maximum grain yield, gross and net returns compared to the rest of the other weed control techniques. Thus, it is concluded that butachlor 50% EC at 2 L ha-1 was more economical, profitable and beneficial than other control treatments in the production of cowpea genotypes in the savannah woodland and rainforest agroclimatic regions of Sierra Leone. Conclusively, the relationship between phytotoxicity and grain yield indicates that the higher the grain yield the lower the phytotoxic effects of the chemicals.

2020 ◽  
Vol 1 (1) ◽  
pp. 87-91
Author(s):  
Indrajeet Niranjan ◽  
◽  
Shashank Tyagi ◽  
Birendra Kumar ◽  
Amit Pradhan

A field experiment was conducted during rabi season of 2018-2019 at research farm of Bihar Agricultural University, Sabour, Bhagalpur to assess the effect of various post-emergence herbicides in chickpea. The results indicated that among different herbicides, post-emergence application of imazethapyr + imazamox @ 60 g a.i. ha-1 at 20 days after sowing recorded significantly lowest weed density & weed dry weight at 60 days after sowing and highest weed control efficiency at harvest, which was statistically at par with quizalofop-ethyl + imazethapyr @ 60+50 g a.i. ha-1 at 20 days after sowing. As a consequence of effective weed control, quizalofop-ethyl + imazethapyr @ 60+50 g a.i. ha-1 at 20 days after sowing recorded significantly highest grain yield, straw yield and harvest index which was significantly superior over hand weeding twice at 30 and 50 days after sowing. In weedy check, uncontrolled weed growth caused significant reduction in grain yield of chickpea. Net returns and B:C ratio was found maximum with quizalofop-ethyl + imazethapyr @ 60+50 g a.i. ha-1 at 20 days after sowing which was significantly superior over weedy check.


2021 ◽  
Vol 27 (1) ◽  
pp. 51-66
Author(s):  
Haseeb Ahmad

An experiment entitled: Maize yield as affected by methods of tillage and weed control methods was conducted at Agronomy Research Farms, The University of Agriculture Peshawar during summer 2016. The study was conducted in randomized complete block design (RCBD) with split plot arrangement having four replications. Tillage practices 1) Chisel plough + rotavator 2) Mouldboard plough + rotavator 3) Cultivator + rotavator and 4) Rotavator were assigned to main plots. Weed management practices included 1) Control, 2) Hoeing 15 days after sowing 3) Hoeing 15 and 30 days after sowing 4) Hoeing 15, 30 and 45 days after sowing, and 4) Herbicide (nicosulfuron) were kept into the subplots. The results revealed that chisel plough + rotavator has significantly reduced weeds m-2 (122, 101 and 125 weeds m-2), weeds fresh weight (19.73 g m-2, 116.35 g m-2 and 252.56 g m-2) and weeds dry weight (6.83 g m-2, 38.69 g m-2 and 80.61 g m-2) at 30, 45 and 60 days after sowing, respectively. The operation of chisel plough + rotavator has produced tallest plants (221.22 cm) with maximum grain rows ear-1 (16), grain yield (3586 kg ha-1) and shelling percentage (78.14%). Among weed control methods, hoeing 15, 30 and 45 days after sowing revealed maximum plant height (226.41 cm), grain rows ear-1 (16), grain yield (3604 kg ha-1) and shelling percentage (79.11%). All weed control methods have showed significant reduction in weeds m-2, weeds fresh weight and weeds dry weight. Interaction was also found significant for weeds m-2 at 60 DAS and grain yield of maize. Lowest weeds (56 weeds m-2) at 60 DAS and highest grain yield (4569 kg ha-1) was recorded when seedbed was prepared with chisel plough + rotavator with 3 hoeings (hoeing 15, 30 and 45 days after sowing). It is concluded that treatment of chisel plough + rotavator and hoeing 15, 30 and 45 days after sowing has significantly produced maximum grain yield of maize crop.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 470E-470
Author(s):  
Jennifer A. Johnson ◽  
Larry Kuhns ◽  
Tracey Harpster

Community waste management programs that include the composting of sewage sludge and yard wastes have become a necessity. Using these composts provides many benefits; however, increased levels of organic matter may reduce the effectiveness of preemergence herbicides. Determining how herbicide application rates may need to be adjusted when composted waste is incorporated into the soil may permit the use of these amendments without any decrease in weed control. This experiment examined the effect of two types of compost (composted sewage sludge and composted yard waste) on the weed control provided by four preemergence herbicides. The soil was a Hagerstown silt loam amended with 10%, 20%, or 30% compost by volume. Each mix was placed in half-gallon cardboard milk cartons. The cartons were seeded at 1/2 and 1/4 inches with a mixture of broadleaved weeds and grasses. Each soil mix was treated with simazine, oxyfluorfen, oryzalin, and metolachlor at two rates. Control was evaluated both visually by number and by the dry weight of the harvested weeds. Preliminary results indicate composted sewage sludge causes a greater reduction in herbicide efficacy than composted yard waste. Oryzalin and metolachlor were affected less than oxyfluorfen or simazine. The experiment was repeated using lower application rates. In one replication the soil mixes from the previous experiment were used. The second replication used a Hagerstown silty clay loam soil with fresh compost. The results of this experiment will provide preliminary information for future field studies designed to determine if the application rates of preemergence herbicides need to be adjusted when fields are amended with composted organic matter.


2020 ◽  
Vol 4 (2) ◽  
pp. 8-15
Author(s):  
O. Danmaigoro ◽  
M. I. Zamfara ◽  
H. Yakubu ◽  
Musa M. Umar

Field trials were conducted in 2017 and 2018 wet seasons at Federal University Dutse Teaching and Research Farm (Latitude 11 46, 39”N and Longitude 9 20, 30”E) in the Sudan Savanna of Nigeria. To evaluate performance of sesame varieties as affected by poultry manure and weed control methods. The treatments consisted of five weed control treatments (pre-emergence application of ButachlorEC50%,  hoe weeding at 3WAS +pre-emergence butachlor EC50%, pre-emergence butachlor EC50%+hoe weeding at 3 and 6WAS, hoe weeding @ 3 and 6WAS and weedy check), three level of poultry manure (5, 10, and 15t/ha) and three sesame varieties (Ben 01, Yandev 55 and Ben 04E. The treatments were laid out in split plot design and replicated three times. The results indicated that weed control methods had significant effect (0.05) on the sesame growth and seed yield comparable to hoe weeding control at 3 and 6WAS where plant height number of leaves,  capsule number per plant and seed yield of sesame were significant higher with the application of butachlor plus hoe weeding at 3 and 6WAS compared to others weed control methods.  Poultry manure application on sesame as 15t/ha gave taller plant height, more number of leaves, higher sesame dry weight, longer capsule length and seed yield of sesame than the other rates while Ben 01(455 and 1043 ) perform better than the others two varieties (Yandev 498, 756 and Ben4E 522 and 765 ) for 2017 and 2018 seasons.  In conclusion,       


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 390C-390
Author(s):  
Robert H. Stamps ◽  
Daniel W. McColley

Five preemergence herbicides (prodiamine 0.5 G, prodiamine 65 WDG, dithiopyr 0.27 G, thiazopyr 2.5 G, and oxyfluorfen + pendimethalin 3 G) were evaluated for weed control and crop safety on 18 plants (Acer rubrum, Agapanthus africanus, Asparagus densiflorus, Camellia sasanqua, × Cupressocyparis leylandii, Cycas revoluta, Galphimia gracillis, Gelsemium sempervirens, Illicium parviflorum, Lantana camara, Loropetalum chinense, Myrtis communis, Ophiopogon jaburan, Plumbago, Quercus virginiana, Rhododendron, Viburnum suspensum, and Zamia floridana. Herbicides were applied at 1.7 kg a.i./ha, except for oxyfluorfern + pendimethalin, which was applied at 3.4 kg a.i./ha. Treatments were applied twice at 4-month intervals. Untreated and weed-free controls were used to determine herbicide effects on weeds and crops, respectively. All herbicide treatments reduced weed growth (dry-weight basis) and weeding times. Major weeds were dogfennel [Eupatorium capillifolium (Lam.) Small], southern crabgrass [Digitaria ciliaris (Retz.) Koeler], yellow woodsorrel (Oxalis stricta L.), tasselflower (Emilia spp.), and hairy crabweed [Fatoua villosa (Thumb.) Nakai]. Based on weed dry weights, overall weed control for the first 4 months was higher for diazopyr, thiazopyr, and prodiamine G than for the combination treatment. At 8 months, weed growth was similar for all herbicide treatments. The combination treatment was acutely phytotoxicity to more crops than the other treatments; however, phytotoxicity varied with crop, active ingredient, and formulation.


2012 ◽  
Vol 60 (3) ◽  
pp. 257-264 ◽  
Author(s):  
F. Takim

Field studies were conducted in 2010 and 2011 at the Teaching and Research Farm of the University of Ilorin, Nigeria (9°29′ N, 4°35′ E) to evaluate the effect of early weed competition on the growth and yield of maize. The experiment was designed as a randomized complete block (RCBD) with a split-plot arrangement and three replications. The main plots consisted of three weed control treatments included weedy (no herbicide), grass weeds (pre-emergence atrazine) and broadleaf weeds (pre-emergence metolachlor), while the sub-plots consisted of six durations of weed infestation (3, 4, 5, 6, 7 and 8 weeks after emergence). The pre-emergence herbicides had a greater effect on weed density and weed dry weight. Weed seedling emergence and weed dry weight increased significantly with an increase in the duration of weed interference. The grasses and broadleaf weeds had a similar influence on the growth and grain yield of maize. Three to five weeks of weed interference gave similar grain yields, which were significantly higher than those obtained in plots that had 6-8 weeks of weed interference. These results suggest that the maize crop must be kept free of weeds for 6-8 weeks after the application of pre-emergence herbicide to minimize weed-crop competition and harvest a good grain yield.


Agriculture ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 163
Author(s):  
Robert Idziak ◽  
Zenon Woznica

Field trials were conducted with preemergence dimethanamid-P + pendimethalin (D + P; 850 + 1000 g·ha−1) and reduced rates (637.5 + 750 g·ha−1 and 452 + 500 g·ha−1, 75% and 50% of label rate), followed by strongly reduced rates of postemergence herbicides nicosulfuron + rimsulfuron + dicamba (N + R + D; 4 + 15.6 + 93.5 g·ha−1, 50%), tembotrione (T; 33 g·ha−1, 50%), mesotrione + nicosulfuron (M + N; 37.5 + 15 g·ha−1, 50%), foramsulfuron + iodosulfuron (F + J; 7.5 + 0.25 g·ha−1, 20%), and nikosulfuron (N; 15 g·ha−1, 33%) applied with methylated seed oil (MSO; 1.0 L·ha−1) and ammonium nitrate (AMN; 2 kg·ha−1) on 3–5 leaves of maize to assess weed control, grain yield, and economic net return. Reduced rate of soil-applied herbicide followed by reduced rates of any postemergence herbicides applied with adjuvants was the most efficacious weed control program, provided the highest grain yield of maize and similar or higher economic net return, despite 44 to 48% lower herbicide input than the program based on soil-applied herbicide mixture only. It brings not only notable economic benefits but also less negative impact on the environment.


1979 ◽  
Vol 93 (3) ◽  
pp. 735-747 ◽  
Author(s):  
S. O. Dina

SUMMARYIn field trials made in 1977, the synthetic pyrethroids Deois and Permethrin offered better protection to cowpea flowers and pods but the crop did not outyield that treated with Nuvacron in grain production. Further evaluation of Decis and Permethrin in 1978 showed that the relationships between rate and insect damage, and yield were curvilinear. On the early crop, Decis at 15 g a.i./ha and lOga.i./ha reduced insect damage to flowers and pods, respectively, below the control but yield differences were not significant from 5 to 50 g. Four or five applications of Decis were most effective in reducing insect damage, but yields obtained from them were not better than that from one application. Permethrin at 12·5 g a.i./ha reduced insect damage below the control but produced grain yield which was significantly lower than 25 g and above.On the late crop, Permethrin was effective from 5 to 25 g in reducing insect damage and providing increased grain yield. One application of Decis was sufficient to reduce pod damage and increase grain yield over the control, but appreciable yields were obtained from the three and four application regimes.A cost/benefit analysis of insecticide application shows that the synthetic pyrethroids compared favourably with Nuvacron. In 1978, two and three applications of Decis gave the highest net returns on the early and late season crops, respectively. Decis appeared most economical at 10 g on the early crop while Permethrin was most rewarding at 62·5 g in the early crop and 10 g in the late crop. The seasonal differences in weather are discussed in relation to the performance of the crop.


1980 ◽  
Vol 20 (102) ◽  
pp. 77 ◽  
Author(s):  
BJ Radford ◽  
BJ Wilson ◽  
O Cartledge ◽  
FB Watkins

A series of field trials was sown on black earth soils on the Darling Downs, Queensland, with five wheat seeding rates x five levels of wild oat infestation. The lowest seeding rate required to produce optimum grain yield at a site was higher in wild oat infested plots than in weed-free plots. Increase in seeding rate reduced the dry weight of wild oats at maturity and increased the dry weight of wheat at maturity until wheat population density exceeded 150 plants m-2. Increase in seeding rate also reduced wild oat seed production, especially at low wild oat population densities.


Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 546-552 ◽  
Author(s):  
Rick A. Boydston ◽  
Matt J. Morra ◽  
Vladimir Borek ◽  
Lydia Clayton ◽  
Steven F. Vaughn

Weed control in organic onion production is often difficult and expensive, requiring numerous cultivations and extensive hand weeding. Onion safety and weed control with mustard seed meal (MSM) derived from Sinapis alba was evaluated in greenhouse and field trials. MSM applied at 110, 220, and 440 g m−2 severely injured onions and reduced onion stand by 25% or more when applied from planting to the one-leaf stage of onions in greenhouse trials. MSM derived from mustard cultivars ‘IdaGold’ and ‘AC Pennant’ reduced plant dry weight of redroot pigweed with an effective dose that provided 90% weed control (ED90) of 14.5 and 3.2 g m−2, respectively, in greenhouse trials, whereas the ED90 of MSM from a low-glucosinolate cultivar ‘00RN29D10’ was 128 g m−2, suggesting that glucosinolate content and ionic thiocyanate (SCN−) production contribute to phytotoxicity of MSM. In field trials, weed emergence, onion injury, and onion yield were recorded following single or three sequential applications of MSM from 1.1 to 4.5 MT ha−1 beginning at the two-leaf stage of onions in 2008, 2009, and 2010. By 8 wk after treatment (WAT), onion injury following MSM sequential applications was 10% or less in all 3 yr. Combined over 2008 and 2009, 48 and 68% fewer weeds emerged 3 WAT with MSM at 2.2 and 4.5 MT ha−1, respectively. In 2010, MSM at 2.2 and 4.5 MT ha−1 reduced the number of weeds emerged 4 WAT by 91 and 76%, respectively. MSM treatment did not significantly affect onion yield or size in 2008 and 2009, but in 2010 onion total yield was reduced by 29% by three sequential applications of MSM at 2.2 MT ha−1. MSM has potential to be used as a weed-suppressive amendment in organic production systems, but the risk of crop injury is substantial.


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