Cultural Weed Control Methods Research Articles

Combining stale seedbed with deep rice planting: a novel approach to herbicide resistance management?

AbstractWater seeding is a common cropping strategy in mechanized rice systems. Water seeding of rice can suppress grass weeds, but it can also encourage aquatic weeds and grass ecotypes that escape deep floodwater. In addition, water seeding prevents many cultural methods of weed control and limits available herbicides. Selection pressure from a limited palette of herbicides has resulted in widespread resistance in rice grown in California. This study examined a novel combination of drill seeding and a stale seedbed (“stale-drill”) as a means of using a nonselective herbicide to manage weeds before rice emergence. In 2016 and 2017, rice cultivar ‘M-206’ was drilled at a rate of 120 kg ha−1 to 1.3-cm, 2.5-cm, and 5.1-cm depths. Planting rice deeper than 1.3 cm delayed emergence by 3 to 4 d. A postplant-burndown (PPB) treatment of glyphosate at 870 g ha−1 was applied just prior to rice emergence. Treatment delays had mixed effects on weed control. PPB treatment was more effective at controlling Echinochloa spp. in 2017, reducing density by 30%, 48%, and 73% at 1.3-cm, 2.5-cm, and 5.1-cm seeding depths, respectively. The greatest overall weed control either year was found with applications of glyphosate + pendimethalin followed by penoxsulam + cyhalofop at 1.3-cm planting depth. Rice stand and yield components were more strongly affected by planting depth in 2017 than in 2016, possibly owing to cool weather immediately after seeding. Yields in 2017 were reduced in deeper plantings by up to 72%. Therefore, if the stale-drill method is implemented with higher-vigor cultivars or higher seeding rates, we see potential in this method as a useful tool for reducing herbicide-resistant weeds in rice fields.

E Efficacy and Economics of Herbicidal Weed Management in Monsoon Rice of Bangladesh

Weed management is a challenging task in sustainable rice production. Physical and cultural methods of weed control are laborious and expensive, whereas chemical control is cheaper and less time consuming despite of some detrimental effect on environment with its inappropriate application. Considering these points, an experiment was conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh, Bangladesh during July–December 2015 to find out appropriate weed management practices for inbred and hybrid rice. The experiment comprised of four rice varieties (two inbred; BRRI dhan49 and Binadhan-7, and two hybrids; Dhani gold and Agrodhan-12); and eight herbicidal weed control treatments (season-long weedy or weed free, Pretilachlor fb Penoxsolum or 2,4-D dimethyl amine, Pendimethalin fb Penoxsolum or 2,4-D dimethyl amine, Pretilachlor or Pendimethalin fb one-time hand weeding). Eleven weed species belonging to five families were observed in the experimental plots. The highest weed density and dry weight were found in season-long weedy treatment and the lowest one was found in Pretilachlor fb one-time hand weeding. The highest above ground crop biomass (9.7 t ha-1) and harvest index (46.3%) were obtained from the hybrid variety Agrodhan-12 and the lowest biomass (8.3 t ha-1) was obtained from the inbred variety Binadhan-7. Season long weed free condition resulted the highest above ground crop biomass (10.9 t ha-1), harvest index (48.7%), highest yield increase over control (213.8), weed control efficiency (100%) and gross return (BDT 141480 ha-1) and the lowest values for all those parameters were obtained from season-long weedy treatment. Season-long weed free treatment combined with Pretilachlor or Pendimethalin fb one-time hand weeding showed the best performance in reducing weed density and increasing above ground crop biomass, but gross return was higher because of high labour wages in these treatments. The highest BCR (2.5) was observed in Pretilachlor fb Penoxsolum. Therefore from economic view point Pretilachlor fb Penoxsolum is the best combination. But from sustainability view point Pretilachlor or Pendimethalin along with one-time hand weeding may be recommended for effective weed management in inbred and hybrid rice during monsoon season.

Morphological Traits Associated with Weed‐Suppressive Ability of Winter Wheat against Italian Ryegrass

ABSTRACTWeed‐suppressive wheat (Triticum aestivum L.) cultivars have been suggested as a complement to chemical and cultural methods of weed control. The objectives of this study were to assess the range of weed‐suppressive ability against Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] existing in winter wheat lines adapted to North Carolina and to identify wheat morphological traits that could facilitate indirect selection for weed suppression in the southeastern United States. Fifty‐three commercially available cultivars and advanced experimental lines were overseeded with a uniform, high rate of Italian ryegrass, evaluated for various morphological traits throughout the growing season, and investigated for weed‐suppressive ability at a total of four field sites. Genotypic differences in Italian ryegrass seed head density (P ≤ 0.05) were detected among the wheat lines. Reduced Italian ryegrass seed head density was correlated (P ≤ 0.05) with high vigor during tillering and heading (Zadoks growth stage [GS] 25, 29, 55), erect growth habit (GS 29), low normalized difference vegetation index (NDVI) (GS 29), high leaf area index (LAI) at stem extension (GS 31), early heading date, and tall height throughout the growing season (GS 29, 31, 55, 70 to 80) in three of four sites. Multiple regression models show that 71% of variation in weed‐suppressive ability was accounted for by final height (GS 70 to 80) and either height or plant vigor at late tillering (GS 29). Thus, breeders could improve weed‐suppressive ability using weighted index selection for genotypes that are tall or vigorous during tillering with tall final height.

Effect of Perennial Ryegrass Overseeding on Weed Suppression and Sward Composition

Pesticide bans in Canada have resulted in a requirement for municipal turfgrass managers to use cultural methods of weed control to provide a safe playing surface for athletes. A field study was conducted to determine if overseeding provides enough competition to decrease weed populations in Kentucky bluegrass athletic turf typically used in municipal parks for recreation. Perennial ryegrass was overseeded at 2, 4, and 8 kg/100 m2 in May, July, or September, and all permutations of these timings in nonirrigated and irrigated trials at the Guelph Turfgrass Institute (GTI) field station in Guelph, and on in-use soccer fields at the University of Guelph campus and in the town of Oakville, Ontario, Canada over 2 yr. Plant cover by species was recorded every other month using a randomized point quadrat method throughout the growing seasons of 2005 and 2006. Weed populations were not affected by overseeding in 2005, a dry growing season. However, when weed populations were high and normal growing conditions existed in 2006, overseeding applications in May/July/September at 4 and 8 kg/100 m2 decreased perennial weed cover, specifically white clover in the irrigated trial and dandelion in the nonirrigated trial at the GTI. An increase in perennial ryegrass was observed in all plots that received an overseeding treatment. Treatments applied on the in-use soccer fields in Oakville and Guelph, which included May/September and May only overseedings, had no effect on weed populations or perennial ryegrass populations compared to the weedy control. Over the short term, high-rate and frequent overseeding with perennial ryegrass appears to provide competition against perennial weeds when weed cover is high and should be considered an important part of a weed management program for municipal turfgrass managers.Nomenclature: 2,4-D; mecoprop; dicamba, dandelion, Taraxacum officinale G. H. Weber ex Wiggers, white clover, Trifolium repens L., perennial ryegrass, Lolium perenne L. ‘Edge’ and ‘Futura 3000’, Kentucky bluegrass, Poa pratensis L.

Integrating physical and cultural methods of weed control— examples from European research

Increasing concerns about pesticide use and a steadily increasing conversion to organic farming have been major factors driving research in physical and cultural weed control methods in Europe. This article reviews some of the major results achieved with nonchemical methods and strategies, especially adapted for row crops (e.g., corn, sugar beet, onion, leek, and carrot) and small-grain cereals (e.g., barley and wheat). In row crops, intrarow weeds constitute a major challenge, and research has mainly aimed at replacing laborious hand-weeding with mechanization. A number of investigations have focused on optimizing the use of thermal and mechanical weeding methods against intrarow weeds, such as flaming, harrowing, brush weeding, hoeing, torsion weeding, and finger weeding. And new methods are now under investigation such as robotic weeding for row crops with abundant spacing between individual plants and band-steaming for row crops developing dense crop stands. The strategic use of mechanical weed control methods in small-grain cereals has been another area of considerable interest. Weed harrowing and interrow hoeing provide promising results when they are part of a strategy that also involves cultural methods such as fertilizer placement, seed vigor, seed rate, and competitive varieties. Although research in preventive, cultural, and physical methods have improved weed control in row crops and small-grain cereals, effective long-term weed management in low external input and organic systems can only be achieved by tackling the problem in a wider context, i.e., at the cropping system level. Basic principles of this approach, examples of cover crop and intercropping use for weed suppression, and an application in a 2-yr rotation are presented and discussed.

Weed control in rose-scented geranium (Pelargonium spp).

Abstract: Field investigations were carried out during 1999 and 2000 to identify effective chemical/ cultural methods of weed control in rose-scented geranium (Pelargonium spp). The treatments comprised pre-emergence applications of oxyfluorfen (0.15, 0.20 and 0.25 kg AI ha(-1)) and pendimethalin (0.50, 0.75 and 1.00kg AI ha(-1)), successive hand weeding, hoeing and mulching using spent of lemon grass (at 5 tonnes ha(-1)) 45 days after planting (DAP), three hand-weedings 30, 60 and 90 DAP, weed-free (frequent manual weeding) and weedy control. Broad-leaf weeds were more predominant than grass and sedge weeds, accounting for 85.8% weed density and 93.0% weed dry weight in 1999 and 77.2% weed density and 93.9% weed dry weight in 2000. Unrestricted weed growth significantly reduced geranium oil yield, by 61.6% and 70.6% in 1999 and 2000, respectively. Pre-emergence application of pendimethalin (0.75-1.00 kgAI ha(-1)) or oxyfluorfen (0.25 kg AI ha(-1)), successive hand-weeding, hoeing and mulching and three hand-weedings were highly effective in reducing weed density and dry weight and gave oil yield comparable to the weed-free check. Application of oxyfluorfen (0.15 or 0.20 kg AI ha(-1)) and pendimethalin (0.50 kg AI ha(-1)) were less effective in controlling the weed species in geranium. None of the herbicides impaired the quality of rose-scented geranium oil measured in terms of citronellol and geraniol content.

Managing soil fertility in organic farming systems

Abstract. Complex relationships exist between different components of the organic farm and the quantity and quality of the end products depend on the functioning of the whole system. As such, it is very difficult to isolate soil fertility from production and environmental aspects of the system. Crop rotation is the central tool that integrates the maintenance and development of soil fertility with different aspects of crop and livestock production in organic systems. Nutrient supply to crops depends on the use of legumes to add nitrogen to the system and limited inputs of supplementary nutrients, added in acceptable forms. Manures and crop residues are carefully managed to recycle nutrients around the farm. Management of soil organic matter, primarily through the use of short‐term leys, helps ensure good soil structure and biological activity, important for nutrient supply, health and productivity of both crops and livestock. Carefully planned diverse rotations help reduce the incidence of pests and diseases and allow for cultural methods of weed control. As a result of the complex interactions between different system components, fertility management in organic farming relies on a long‐term integrated approach rather than the more short‐term very targeted solutions common in conventional agriculture.

Non‐chemical weed management in organic farming systems

Concern about potential increases in weed populations without the use of herbicides has limited the uptake of organic farming. However, as both public demands for organic produce and the profile of organic farming have increased in recent years, so too has the range of weed control options. Progress in cultural methods of weed control has included the use of novel weed‐suppressing cover crops, and the identification of specific crop traits for weed suppression. Direct weed control has also seen developments, with new implements appearing on the market that could benefit in the future from sophisticated machine guidance and weed detection technology. Advances in novel techniques such as steaming have also been made. Many weed control operations in organic systems present the grower with conflicts, and both these and many of the most recent developments in organic weed control are reviewed. An increase in our understanding of weed biology and population dynamics underpins long‐term improvements in sustainable weed control. The outcome of these studies will benefit conventional and organic growers alike. Emphasis is given to the need for flexibility and a combination of weed biology knowledge, cultural methods and direct weed control to maintain weed populations at manageable levels.

Integrated weed management in ratooned sugarcane

A field experiment was conducted during the main season of 1999 2001 at Tamil Nadu Agricultural University, Coimbatore, to find out the economical and effective integrated weed management practice to control the weeds in ratooned ( Co 86032 ) sugarcane. The use of pre emergence herbicides did not have any adverse effects on the ratoon sproutings. Various integrated weed management practices were compared with chemical and cultural methods of weed control. All the integrated weed control practices proved effective in controlling the weed growth and increasing the cane and sugar yields compared with use of herbicides alone, and were found on par with conventional method of 2 hand weedings at 30 and 60 days after ratoon initiation. Pre emergence application of atrazine at 2.00 kg a.i./ha combined with 1 hand weeding at 45 days or conventional method of 2 hand weedings at 30 and 60 days were found more effective and economical. None of the weed control treatments affected the juice quality significantly.

Use of sorghum allelopathic properties to control weeds in irrigated wheat in a semi arid region of Punjab

Conventional methods of weed control are weather dependent, costly and labour intensive. Indiscriminate use of chemicals for controlling weeds may pose environmental problems. Sorghum allelopathy is a new technique, which has been tested for controlling weeds of wheat ( Triticum aestivum L.) as a substitute for chemical herbicides to reduce environmental pollution. Mature sorghum herbage contains a number of water-soluble secondary chemical substances (allelochemicals). Sorghum allelopathy can be used as sorgaab (water extract of mature Sorghum bicolor L. Moench plants obtained after soaking in water for 24 h and sprayed as a natural herbicide), sorghum mulch, sorghum soil incorporation and in crop rotation. Two experiments were conducted. In Experiment 1, allelopathic effects of sorghum stalk incorporation into soil and sorgaab foliar spray along with chemical and cultural weed control methods on the growth of different rabi (winter) weeds and on the growth and yield of wheat were studied. In Experiment 2, the effects of concentration (5 and 10%) and frequency of sprays of sorgaab on the growth of weeds and wheat were compared with hand weeding and chemical herbicides. Sorgaab controlled up to 35–49% weeds and increased wheat yield by 10–21%. Mature sorghum chopped herbage (2–6 Mg ha −1) incorporated in the soil at sowing controlled up to 40–50% weeds and increased wheat yield by 15%. Two foliar sprays of 10% sorgaab at 30 and 60 days after sowing was the most economical method for controlling weeds in wheat with maximum net benefits and 535% marginal rate of return. Weed control through hand weeding and/or chemical herbicides was found to be uneconomical due to higher costs involved in both the cases. Sorgaab can be used as a natural weed inhibitor in wheat.

The Principles and Practice of Weed Control for Notillage Soyabean in Southern Brazil Using the Bipyridyl Herbicides

Abstract An ICI survey of the arable area of southern Brazil in 1971 confirmed the urgent need for some form of conservation tillage system for soyabean wheat primarily to control soil erosion. A practical system of no-tillage soyabean was developed for N. Parana, with weed control based on careful crop residue management and sprays of paraquat mixed with either linuron or metribuzin. The marked superiority of these mixtures over paraquat alone for the control of vigorous annual grasses was noted. This effect is, in part attributed to the capacity of metribuzin and linuron (along with other herbicides) to inhibit photosynthesis, thereby facilitating the translocation of paraquat. Where residual herbicides are not used, diuron at low rates in suitable formulation proved the best additive for paraquat. Problem broadleaved weeds are controlled by adding 2, 4-D to paraquat. Temperature, rainfall, the presence of fallows and the interval between harvest and the next planting, all affect pre-plant weed control for no-till soyabean. A key issue is to prevent excessive stands of weeds. Control within the crop can be provided by shielded, directed sprays of paraquat for which tractor mounted sprayers were developed. Recent discoveries of pre- and post-emergence selective herbicides provide improved and alternative in-crop weed control options. Crop diversification and further general no-till research show promise of further rational, chemical and cultural methods of weed control.

Cultural and Chemical Methods of Weed Control in Transplanted Rice

There was no significant different between the preplant application of paraquat at 0.8 kg a.i./ha and puddling six times. Hand weeding and working rotary weeder recorded the maximum yield when compared to the herbicides rogue, butachlor propanil and 2,4-D, which were in turn better than unweeded check. The combination of post emergence application of propanil and paraquat was also not effective. But propanil combined with thorough land preparation and paraquat combined with hand weeding recorded the same yield as good land preparation and cultural methods of weed control.

Effect of Chemical and Cultural Methods of Weed Control on Transplanted Rice

Machete granules and Stam-F, 34 are very effective to control the weeds in tran- splanted rice when they are supplemented with one hand weeding 5 weeks after plant- ing. The herbicides lack residual activity and do not control effectively the regeneration of particularly perer.nial weeds. Machete granules at 2.5 kg a. l/ha is more effective and economical than Stum F-34 at 3.0 ka a. I. / ha individually and in combination with one hand weeding.

Long-term effects of primary cultivations on crop yields in a four-course rotation

SUMMARYAn experiment is described which investigated for a period of 12 years the effects of four methods of basic cultivation – ploughing, rotary cultivating, cultivating and discing – on crop yields in a four-course rotation of winter wheat, sugar beet, spring barley followed by either potatoes (on one half of each main plot) or ley (on the other). The cultivations were carried out at two different times and each crop was grown at two levels of fertilizer.The method of cultivation had no effect on the yield of barley when weeds were controlled by chemicals but, in the absence of such control, the three deeper working methods of cultivation gave higher yields than discing towards the end of the experiment. In the case of wheat, ploughing generally led to the highest yields and rotary cultivating led to higher yields than either cultivating or discing after the ley. Discing led to relatively low yields, particularly with cultural methods of weed control at the lower level of fertility.With the sugar-beet crop, yields of sugar were higher in all rotations after ploughing than after cultivating or discing, irrespective of the method of weed control and although yields after rotary cultivating were similar to those after ploughing in the second rotation they did not consistently exceed those after cultivating or discing in the other two rotations. With discing, in the absence of chemical weed control the yields were markedly reduced in the last rotation period. Ploughing also led to the highest yields of potatoes but there were no consistent differences between the other methods and an apparent trend to lower yields after discing in the absence of chemical methods of weed control had not reached significance by the end of the experiment.It was concluded that ploughing was a more reliable method of seedbed preparation, not only with regard to consistency of performance under different conditions but also with regard to depth of working and extent of weed control.Ploughing appeared to be of particular value with the root crops used but the other methods led to satisfactory yields of the cereals grown after roots.

Effect of chemical and cultural methods of weed control on the yield and growth of maize

(1969). Effect of chemical and cultural methods of weed control on the yield and growth of maize. PANS Pest Articles & News Summaries: Vol. 15, No. 2, pp. 200-203.