Reduced Weed Dry Matter Research Articles

Evaluation of Sowing Methods and Herbicide Mixtures for Weed Management and Productivity in Sesame (Sesamum indicum L.)

Sesame is an oil seed crop with great economic value. However, the production of this crop has been limited by weed competition, which prompted a field experiment during the 2021 cropping season in two locations: Teaching and Research Farm, Kwara State University, Malete, and National Centre for Agricultural Mechanization (NCAM), Idofian, Ilorin, Kwara, Nigeria. The aim was to determine the treatment combinations of sowing methods and herbicide mixtures for the effective management of weeds and for increasing sesame productivity in the southern Guinea savanna of Nigeria. The experiment consisted of twenty treatments comprising two sowing methods (dibbling and drilling) and ten weed control methods. Results showed that all the weed control methods reduced weed dry matter (67.15–186.20 and 42.00–92.45 g/m2) than the weedy check (291.55 and 155.55 g/m2) at Malete and NCAM, respectively. They also reduced the weed density (48.40–68.45 and 34.00–50.00/m2) compared to the weedy check (103.60 and 73.15 g/m2) at Malete and NCAM, respectively, from 6 to 12 weeks after planting (WAP). Dibbling (85.15 and 48.81 m2) proved superior to the drilling method (172.42 and 51.58/m2) for the management of weeds from 6–12 WAP and for promoting higher crop yield (dibbling: 78.90 and 422.70 kg/ha; drilling: 37.50 and 326.80 kg/ha) in Malete and NCAM, respectively. The treatment combinations with the highest gross margin were hoeing twice at 3 and 6 WAP × dibbling ($ -191.15 and $ 318.57), pendimethalin (P) + diuron (D) at 0.5 + 0.5 kg a.i./ha ($ -199.88 and $ 182.43), 2.0 + 1.5 × dibbling ($ -273.59 and $ 156.65) and butachlor (B) + diuron (D) at 1.5 + 1.0 kg a.i./ha × drilling ($ -269.59 and $ 177.38) at Malete and NCAM, respectively. Therefore, it is recommended that the dibbling sowing method at a spacing of 30 cm × 30 cm and thinned to 3 plants/stand integrated with herbicide mixtures of pendimethalin at 0.5 + 0.5 kg a.i./ha is recommended as an alternative to hoe weeding for effective weed control, higher yield of sesame, and economic returns.

Nutrient uptake by weeds and soybean crop as influenced by weed management practices in Vertisols

A field experiment was conducted during kharif season of 2021 to study the effect of weed management practices on uptake of nutrients by weed and soybean at Kota (Rajasthan). The results indicated that weeds in soybean depleted the soil fertility by removing 69.2 kg ha-1 N, 12.4 kg ha-1 P and 76.7 kg ha-1 K under unweeded check. All weed management practices reduced weed dry matter and nutrient uptake by weeds at 30 and 60 days after sowing (DAS). Two hand weedings and ready mixture of fomesafen + fluazifop-p-butyl @ 220 g a.i. ha-1 proved significantly superior in reducing weed dry matter and nutrient uptake by weeds at 30 and 60 DAS over rest of the treatments. All weed control measures significantly enhanced seed and straw yield of soybean over weedy check. Two hand weedings and mixture of fomesafen + fluazifop-p-butyl @ 220 g a.i. ha-1 , sodium acifluorfen + clodinafop-propargyl @ 245 g a.i. ha-1 and propaquizafop + imazethapyr @125 g a.i. ha-1 as post emergence (PoE) were at par and were found to be significantly superior over rest of the treatments in enhancing seed and straw yield. Ready mix application of fomesafen + fluazifop-p-butyl @ 220 g a.i. ha-1 , propaquizafop + imazethapyr @ 125 g a.i. ha-1 and sodium acifluorfen + clodinafop-propargyl @ 245 g a.i. ha-1 (PoE) significantly reduced the NPK uptake by total weeds and significantly improved nutrient uptake by soybean and consequently resulted higher seed yields.

Exploiting Olive Mill Byproducts and Other Waste for Organic Weed Management

Weed management represents one of the most serious and costly challenges in organic crop production systems. Agricultural waste/byproducts might present phytotoxicity that can be exploited to control weeds. Two experiments were designed to study the effects of four concentrations of olive vegetation water (OVW) and a control water treatment (with no OVW) on cheeseweed (Malva parviflora L.) seed germination in petri dishes and pots. In a third experiment, two rates of four composts (crop residue mix (CR), olive pomace (OP), dairy/horse manure (DM), and an OP/DM mix) were mixed into a clay‒loam soil at 0.10 or 0.20 L L−1, to assess their effects on weed number and biomass, in addition to bell pepper (Capsicum annuum L.) growth. In the petri dish experiment, the three highest OVW concentrations completely prohibited germination during the five-week duration of the study. For the pot experiment, 25 mL application of OVW significantly delayed and reduced cheeseweed germination, with the reduction being proportional to the concentration of OVW. In the third experiment, composts reduced weed dry matter (composed mostly of purslane (Portulaca oleracea L.)), with the CR compost being the most effective, reducing total weed biomass by 67% compared to the control. CR10 and DM10 tended to increase bell pepper yields, although none of the plant parameters was significantly affected by the compost treatments.

Tank-mix insecticide and herbicide application effects on weeds, insect-pest menace and soybean productivity in Semi-Arid Northern Plains of India

The effects of herbicides, alone application or in combination with insecticides, on performance of soybean [Glycine max (L.) Merrill] were examined at ICAR- Indian Agricultural Research Institute, New Delhi during rainy seasons of 2013 and 2014. Alone application of imazethapyr 10 SL @ 1.0 l/ha or in combination with indoxacarb 14.5 SC @ 300 ml/ha and rynaxypyr 20 SC @ 100 ml/ha lowered monocot and dicot weed count, reduced weed dry matter and increased weed control efficiency in comparison with other herbicide and insecticide applications, individual or in combinations. These results suggested that the imazethapyr can effectively control different categories of weeds, especially of monocots in soybean field. However, seed yield, net returns and B: C ratios were higher in the quizalofop ethyl 5 EC (1.0 l/ha) applied plots followed by combined application of rynaxypyr 20 SC (100 ml/ha) + quizalofop ethyl 5 EC (1.0 l/ha)).

Effect of weed management and sulphur on weed dynamics, soybean (Glycine max) yield and associated quality traits

A field experiment was conducted during rainy seasons of 2011 and 2012 at Udaipur to evaluate the effect of weed control and sulphur on yield and quality of soybean [Glycine max (L.) Merrill]. The twenty eight treatment combinations comprising 7 weed management treatments (weedy check, pendimethalin 1.0 kg ha-1 pre- emergence, quizalofop-ethyl 50 g ha-1 and imazethapyr 100 g ha-1 post-emergence at 15 DAS, pendimethalin, quizalofop-ethyl and imazethapyr followed by hoeing and weeding at 30 DAS) in main plot and 4 rates of sulphur application (00, 20, 40 and 60 kg ha1) in sub plot were laid out in split plot design with three replications. All weed control treatments reduced weed dry matter at harvest during both the years. Pendimethalin followed by hoeing and weeding at 30 DAS was significantly superior in reducing weed dry matter of broad-leaved, narrow-leaved and total weeds at harvest over rest of the treatments. All weed control treatments significantly enhanced straw and biological yield of soybean over weedy check. Pendimethalin followed by hoeing and weeding at 30 DAS produced significantly higher pooled seed (2168 kg ha-1), straw (3167 kg ha-1) and biological (5335 kg ha-1) yields compared to other treatments. Sulphur rates had no significant effect on weed dry matter at harvest. Across the years, increasing level of S application up to 40 kg ha-1 resulted in significantly increased straw yield, biological yield and harvest index of soybean. Increasing rate of sulphur application up to 40 kg ha-1 tended to significantly increase protein and oil yield.

Growth and weed suppression ability of common and new cover crops in Germany

Cover crops have a wide-ranging influence on the agroecosystem and create multiple benefits for farmers. A major benefit of cover crops is the suppression of weeds during fall and winter, which can help to reduce soil tillage and herbicide use. However, only a small number of cover crop species are currently grown in Germany. To enlarge this number, four new cover crop species including tartary buckwheat, forage radish, red oat and grain amaranth were tested in comparison with common cover crop species such as white mustard, oilseed radish and phacelia. Emergence, soil coverage, dry matter production and weed suppression ability was assessed for all cover crop species. White mustard emerged faster than all other cover crops and produced the highest amount of shoot dry matter at both locations in southwest Germany twelve weeks after planting (WAP). Oilseed radish was the only cover crop that reduced the weed dry matter in all experiments eight WAP. Phacelia was able to reduce weed density by 77% at Meiereihof twelve WAP. Tartary buckwheat offered the highest soil coverage four WAP, produced the greatest shoot dry matter eight WAP and reduced weed dry matter by more than 96% at Meiereihof and Ihinger Hof twelve WAP. Forage radish produced the highest root dry matter and reduced spring weed density by more than 81% in all experiments. Red oat and grain amaranth emerged slowly, produced less biomass than other cover crops and did not suppress weed growth. The results show that tartary buckwheat and forage radish are well suited as new cover crops in Germany due to their fast growth and good weed suppression ability.

Regulation of cover crops and weeds using a roll-chopper for herbicide reduction in no-tillage winter wheat

There is increased interest for no tillage systems as they contribute to soil and water protection and can reduce labour and fuel costs. In such systems, cover crops and weeds are usually regulated before sowing the main crop using nonselective herbicides, usually glyphosate. However, less herbicide-dependent regulation methods are desirable to reduce risks emanating from the widespread herbicide use. Therefore, a two-years field study was conducted in Switzerland to evaluate the ability of a roll-chopper to regulate cover crops instead of using the non-selective herbicide glyphosate. In addition to this, it was tested whether cover crops have the ability to suppress weeds. The experiment was performed with a total of 11 different cover crops (oilseed radish, white mustard, blue lupine, common vetch, spring oat, amaranth, buckwheat, sunflower, phacelia, and the cover crops mixtures of field bean and spring oat as well as spring oat, common vetch and field pea). In both years, all cover crop species suppressed weeds resulting in reduced weed dry matter production in autumn compared to the control treatments where no cover crop was sown. In spring, soil coverage of weeds was similar in all treatments when the cover crops were regulated with glyphosate. In contrast, soil coverage of weeds was significantly higher when cover crops were regulated with a roll-chopper. In the first study year, soil coverage of weeds was about sixty times lower when the cover crops were regulated with glyphosate compared with regulation with the roll-chopper, while in the second study year it was about nine times lower. Winter wheat yield was higher in both years when glyphosate was applied to regulate cover crops and a selective herbicide in spring compared to using a roll-chopper and no herbicide application. It seemed that cover crop regulation method in autumn was the major factor determining weed density in spring as well as winter wheat yield. The present study indicates that cover crops have the potential to reduce weeds in no-tillage systems. Mechanical regulation of cover crops using a roll-chopper offers the possibility to reduce herbicide use, however, roll-chopping cover crops as a stand-alone regulation tool would not reduce natural weed populations sufficiently to sustain winter wheat yield. However, roll-chopping combined with other weed management strategies such as selective herbicide application might be sufficient to achieve a main crop yield comparable to the standard treatment using glyphosate.

Weed control via intercropping with gliricidia: I. cotton crop

The majority of cotton grown commercially in the world has white lint, but recently, there has been a growing interest in colored lint cotton in several countries, including Brazil. The use of naturally-colored fiber reduces chemical pollution. The objective of this paper was to evaluate cotton cultivar fiber yield in response to weed control via intercropping with gliricídia. Cultivars BRS-Verde (greenish fibers), BRS-Rubi (reddish brown fibers), BRS-Safira (brown fibers), and BRS-187 8H (white fibers) were submitted to the following treatments: no hoeing, two hoeings (at 20 and 40 days after transplanting), and cotton intercropped with gliricídia. In the intercropped treatment, gliricídia was planted between rows of cotton plants, using one seedling pit-1, in pits spaced 50.0 cm apart. Twelve weed species predominated in the experiment, many of them belonging to the Poaceae family. Weeds occurred at different frequencies and in a non-uniform manner in the experimental area. Cultivars did not influence weed dry matter. Intercropping with gliricídia reduced weed dry matter but did not prevent reductions in cotton fiber and seed cotton yield, which were higher in hoed plots. Cultivar BRS Safira had the highest fiber yield, but no differences were observed between cultivars regarding to seed cotton yield.

Effect of Mucuna Fallow on Weed Dry Matter and Composition in Succeeding Maize

ABSTRACT Weeding requires a major proportion of labour in farming of smallholders in Africa. Any technology that can effectively reduce the weeding requirement increases the productivity of the household. Studies were conducted on farmers' fields in the Sunyani District (2°8' to 2°31′W latitude, 7°7' to 7°36' N longitude), located in the Forest-Savannah Transitional Zone of Ghana in 1999 and 2000 to assess the impact of two different slash-and-mulch Mucuna fallow systems on weed dry matter (DM), weed density and frequency in succeeding maize compared with the prevailing slash-and-burn natural fallow system. Late maturing Mucuna pruriens (L.) DC var. utilis (Wright) Burck reduced weed DM by 58% in 1999 and 68% in 2000. The system with the local early maturing Mucuna variety did not reduce weed DM significantly. On the whole, 58 weed species from 27 families were identified. The most dominant species were Chromolaena odorata (L.) R.M. King & Robinson, Centrosema pubescens Benth., Euphorbia heterophylla Linn, and Mucuna spp. volunteer seedlings. The M. pruriens system reduced eight persistent weeds (frequency of occurence < 20%) both in frequency and average density compared with the short season natural fallow treatment. In contrast, only two persistent weed species were affected in the same way by the system with the local Mucuna variety, while six persistent weeds increased in frequency of occurence and seedling density. Poaceae species were negatively affected by the Mucuna systems. While in the natural fallow treatment Poaceae comprised 27.8% of all species identified, their proportions were reduced to 23.1% and 21.7% after fallow with the local Mucuna variety and M. pruriens, respectively. The greater weed suppressing effect of M. pruriens is considered to be a result of its longer life span than the early maturing local variety.

Weed management at the time of perennial cereal rye establishment

Perennial cereal rye (PC rye) is a new crop that is being developed at the Lethbridge Research Centre for the production of silage for cattle. Its ability to compete with weeds during establishment and tolerance to herbicides for weed control was unknown. Therefore, experiments were established with PC rye, and several herbicide treatments were applied to test crop tolerance and weed control. PC rye was not injured by bromoxynil/MCPA, 2,4-D, thifensulfuron/tribenuron, fenoxaprop, clodinafop-propargyl, and tralkoxydim. Combinations of herbicides for broadleaf weed control and annual grass control usually reduced weed dry matter (DM) to &lt; 5 g m-2 in the establishment year. Weeds made up 20 to 36% of the total DM when herbicides were not applied. However, this level of weed content did not affect the digestibility of the forage samples or the total DM produced as weed DM compensated for reduced PC rye yield in weedy plots. Also, the presence of weeds during establishment of PC rye did not affect weed content or PC rye yields the year after establishment. Key words: Acid detergent fibre, digestibility, neutral detergent fibre, perennial cereal rye, weed control, yield

Weed management in turmeric (Curcuma longa) through integrated approaches

A field study was conducted at Ludhiana during 2006-07 and 2007-08 and at Nawanshah during 2007-08 to find out effective and economical approaches for weed management in turmeric (Curcuma longa L.). Pre-emer- gence pendimethalin 1.0 kg, metribuzin 0.70 kg and atrazine 0.75 kglha, each integrated with one hoeing at 60 days, paddy straw mulch 6 t and 9 tlha; paddy straw mulch 6 t (recommended), 9 tlha alone and 6 tlha + two hoe- ing at 60 and 90 days; three hoeing at 30, 60 and 90 days and unweeded control were evaluated. Losses in rhi- zome yield due to weeds vary from 63.9 to 76.5%. Straw mulch 9 tlha significantly reduced weed dry matter and recorded 29.2% higher rhizome yield than 6 tlha. Averaged over two locations, pendimethalin + straw mulch 9 tlha revealed the highest weed control efficiency (84.2%), fresh rhizome yield (29.6 tlha), herbicide efficiency index (1 1.2), net returns (103 0 l o 3 Rslha) and benefit : cost ratio (2.30) and was at par with metribuzin and atrazine, both integrated with straw mulch 9 tlha. The fresh rhizome yield with straw mulch 9 tlha + herbicide combination was 48.2, 14.9, 15.3 and 225.5% higher than straw mulch 6 t, 9 tlha alone, 6 tlha + herbicide and unweeded con- trol, respectively. Different weed control measures led to 104.8ii289.1, 72.7ii220.4 and 90.5A278.1% increase.in N, P and K uptake by crop, respectively, over unweeded control. Uncontrolled weeds removed 60.6, 59.9 and 73.6% of total nutrients utilized by both crop and weeds. Integrated use of paddy straw mulch 9 tlha with either of pendimethalin 1.0 kg, metribuzin 0.70 kg and atrazine 0.75 kglha was adjudged very effective for weed control and attaining the highest productivity and profitability in turmeric.

Field pea cultivar and weed response to crop seed rate in western Canada

Weed competition is a serious limitation to field pea (Pisum sativum L.) production. Trials were conducted in northeastern Saskatchewan to determine the effects of field pea growth habit, stand density and herbicide treatments on weed growth and on field pea stand and yield. Century, a long-stem leafy type, Tipu, a long-stem semi-leafless type, and Express, a short-stem leafy type, were seeded at 6, 12, 25, 50 and 100 seeds m−2. Some of each cultivar was unsprayed sprayed with a sethoxydim-metribuzin tank-mix for control of grass and broadleaf weeds. Field pea growth habit (cultivar) did not affect number of weeds, but increasing stand density (seed rate) reduced weed numbers in all 3 yr. Express reduced above-ground dry matter production of broadleaf weeds in 1988 and 1991. Increasing seed rate reduced above-ground dry matter production of weeds in all 3 yr. Field pea yield increased with increasing seed rate to a rate between 50 and 100 seeds m−2. Herbicide application reduced weed dry matter production, with the largest effect at low field pea populations. Despite differences in growth habit, the three cultivars competed similarly with weeds. High populations of field peas competed well with weeds and may not require herbicide application, but if producers retain thin stands, good weed control will be critical to attaining high crop yield. Key words: Field pea, Pisum sativum L., seed rate, weed competition, growth habit

Effect of Adjuvants on Herbicide Efficacy in Controlling Weeds in Wheat

Two adjuvants, Triton 11 XE (Isoctyl phenyl polyethoxy ethanol) and urea were tank mixed with four herbicides, methabenzthiazuron [N-(benzothiazol-2-yl)N,N′-dimethyl urea] at 1.0 and 1.5 kg ai/ha, terbutryn [N-(1,1-dimethylethyl)-N′-ethyl-6-(methylthio)-1,3,5-triazine-2,4-diamine] at 0.50 and 0.75 kg/ha, metoxuron [N-3-chloro-4-methoxyphenyl)N,N-dimethylurea] at 1.0 and 1.75 kg/ha, and isoproturon [(N-(4-isopropylphenyl)-N,N-dimethylurea] at 0.50 and 0.75 kg/ha and applied to weeds in wheat. Metoxuron reduced weed dry matter by 90% over a 2-yr period. Isoproturon, terbutryn, and methabenzthiazuron reduced weed dry matter by 82%. Tank-mixing of Triton 11 XE at 0.5% (v/v) with metoxuron at 1.0 kg ai/ha, terbutryn at 0.5 kg/ha, isoproturon at 0.5 kg/ha, and methabenzthiazuron at 1.0 kg/ha reduced weed density and biomass by 52 to 67% and enhanced grain yield by 33% over herbicide alone. None of the herbicides had any significant interaction with adjuvants in terms of weed control and grain yield.

Weed control by herbicides in knol khol and radish

Abstract In studies on chemical weed control in some cruciferous crops, butachlor, fluchloralin and oxyfluorfen proved to be effective for transplanted knol khol (kohl rabi) both in terms of reduced weed dry matter and crop yield. For white radish, alachlor and butachlor at 2.0 kg, and fluazifop‐butyl∗ at 0.75 kg a.i./ha, were suitable herbicides. For red radish, alachlor, butachlor and fluchloralin were equally effective in controlling weeds when compared with hand weeded control. Fluazifop‐butyl controlled both Cyperus iria and C. rotundus very effectively. Generally, herbicide treatments were found to be more economical than hand weeding in all the three crops tested.

Weed control by herbicides in cole crops and cucurbitaceous crops

Abstract In studies on chemical weed control in cole and cucurbitaceous crops, oxyfluorfen ('Goal') and fluchloralin ('Basalin') proved to be effective herbicides for transplanted cabbage and cauliflower, both in terms of reduced weed dry matter and increased crop yield. For pumpkin, squash and watermelon, butachlor at 2 kg a.i. ha proved to be a suitable herbicide. A significant increase in yield of watermelon was observed using butachlor 2 kg a.i./ha compared with the handweeded control. In bottlegourd, fluchloralin at 2 kg a.i./ha and alachlor and butachlor at 2.5 kg a.i./ha gave better control of weeds compared with the handweeded control. Ridge gourd and bitter gourd tolerated alachlor, butachlor and fluchloralin well. Oxadiazon reduced the yield in ridge gourd. In bitter gourd yield increases were observed with use of alachlor and butachlor at 2 kg a.i./ha, fluchloralin 0.75 kg a.i./ha and oxadiazon at both concentrations. Generally herbicide treatments were found to be more economical than handweed...