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Broadleaf weed control with abrasive grit during raspberry establishment
Abstract
Growers desire more techniques to control weeds in horticultural crops that are grown organically and consumed directly, such as red raspberry. Abrasive grit emited via high air pressure is a new method for controlling weeds. Grit derived from corn cobs was examined for its efficacy during the year of raspberry establishment for two to three years at three sites (seven site-years) and compared with efficacy of hand-weeding as well as no weed control. Grit was applied once or twice weekly after raspberry transplantation in spring until weed emergence ceased in mid to late July. Weeds and raspberry growth were assessed in August. Grit was effective in controlling broadleaf weeds, averaging 94% control across site-years, but control of grass weeds was <10%. Total weed (broadleaf plus grass) control across site-years ranged from 51 to 96% and averaged 78%. Raspberry cane growth was affected by weeds, and grit-weeding at least partially alleviated these effects. Thus, abrasive grit allows growers to manage broadleaf weeds effectively without herbicides or soil tillage. However, additional research is needed to determine the correct amounts and timing of grit applications, as well as more efficacious types of grit, to control grass weeds.
... Small annual broadleaf weed seedlings can be controlled effectively with pressurized corn cob grit (Erazo-Barradas et al., 2018;Forcella et al., 2020), but management of perennial weeds, especially grasses, is more difficult . With corn cob grit, the amount of grit needed and the time required to abrade perennial weeds to eliminate their influences on perennial crops is too high to be practical for even high-value horticultural crops (Forcella, Poppe and Hoover, 2023). ...
... These grit types were bone meal, eggshell, hazelnut shell, and sugar beet pulp, each with three different particle size classes (0.5, 0.7, and 1.0 mm). Corn cob grit (1-2 mm) also was included for comparison because of its use in prior experiments (e.g., Forcella et al., 2020). ...
Two sequential experiments examined the effects of abrasive grit on seedlings of grass weeds and young shoots of perennial weeds. First, four types of grit derived from agricultural residues (bone meal, eggshell, hazelnut shell, and sugar beet pulp) were tested under high air pressure in a controlled environment for their abilities to abrade seedlings of an annual grass, Setaria faberi Herrm., and the perennials Festuca arundinacea Schreb., Poa pratensis L., and Elymus repens (L.) Gould. Differing grit particle sizes and amounts, as well as weed seedling stages, were examined for efficacy after abrasion by each type of grit. Second, hazelnut shell grit was used to control P. pratensis and Taraxicum officinale Weber in field trials with aronia ( Aronia melanocarpa [Michx.] Elliott), which is a new, shrubby, berry crop in the midwestern USA. Grit weeding was compared to two other treatments: manual weeding (hand-hoeing + hand-pulling) and no weed control (weedy check) over two years. In the grit comparison experiment, control of S. faberi was highest for egg-shell grit (63–100% across grit particle sizes, rates, and seedling stages) and least for sugar beet pulp (17–97%). The former grit had the highest bulk density of all grits, and the latter had the lowest bulk density. For damage to perennial weeds, egg-shell grit performed best (17–80% control) and bone meal least (10–47% control). Elymus repens was controlled better than other perennial grasses, especially by eggshell grit (up to 73% control) and hazelnut shell grit (up to 67% control) with particle sizes of 1–2 mm. In the aronia experiment, both grit abrasion and manual weeding achieved comparable levels of weed suppression (≥87%) and required similar amounts of cumulative seasonal time spent weeding (3–4 min per shrub). Thus, applications of abrasive grit derived from agricultural residues are potential alternatives for non-chemical management of weeds in aronia and, perhaps, in other high-value perennial crops.
... With this technique, abrasive grit derived from soil (e.g., quartz sand) or agricultural residues (e.g., grape pomace, olive pits, nut shells) is discharged under high air pressure to abrade and kill weed seedlings [6] . With proper aiming, timing, and application rates, abrasive grits can suppress weeds and leave crops unscathed [7] . To date, abrasive grits have been tested successfully for selective control only in annual crops. ...
... METHOD single nozzle grit applicator as pictured in [9] . Grit particles were about 0.5 mm diameter and had a specific gravity of 0.43 ± 0.005 g·ml −1 ; these characteristics matched grits used by others [7] . The nozzle of the grit applicator typically was positioned 30 cm from the target weeds. ...
New forms of weed control may be useful in apple orchards. Abrasive corn cob grit applied under high air pressure was tested for the control of weeds in an established apple orchard over two years. Additionally, efficacy of abrasive grit-weeding was compared to that of hand-weeding. As expected, hand-weeding nearly eliminated all weeds. In contrast, grit-weeding achieved about 90% control of broadleaf weeds, only 15% control of grass weeds, and 70 to 80% control of all weeds. Much of the time and amount of grit used was devoted to suppressing grass weeds. Relatively soft corn cob grit easily abraded and controlled broadleaf weeds. However, harder and more angular grit materials may be needed to control annual and perennial grasses.
... Several gumla species are reported to be tolerant to various post-emergence herbicides (Dylan et al., 2023). The application of agroresidual mulch from legume plants and abrasive sand, in the weed germination phase, significantly reduces corn crop yield losses due to the weeds C. rotondus and D. sanginalis (Forcella et al., 2020). This finding is in line with the results of this study regarding low corn yield losses in peanut and cowpea insert crop treatments due to suppressed population and growth of sedge and poaceae weeds. ...
The aim of the research is to examine the effect of intercropping corn with leguminous crops on weeds and land use efficiency. The experimental research method was designed using a randomized complete block design (RCBD) with three blocks. The treatments tested were monocrop planting patterns and intercropping between corn and leguminous crops. The results of the research showed that 16 weed species were found with high species diversity, evenness, dominance, and abundance, so that there were six dominant species that existed during plant growth. Peanuts and cowpeas are suitable for intercropping with corn because they can suppress the population and growth of weeds. Soybeans, green beans, and red beans are not suitable because they are not effective in suppressing the population and growth of weeds and compete with corn, so that corn yield losses due to competition are 38.20%–40.96% and due to weed competition, they reach 62.37%–63.77%. The best ecological and agronomic land use efficiency was obtained by intercropping corn with peanuts and cowpeas, with NKL values based on dry biomass weights of 1.90 and 1.89 (NKL > 1) and dry seed weights of 1.79 and 1.78 (NKL > 1).
The aim of the research was to determine the diversity, distribution, dominance, and yield loss of corn due to competition from broadleaf weeds. Descriptive research method with direct survey techniques of research objects. Data were collected using 10 sample plots measuring 1 m2, which were placed using random sampling. Observation parameters include the population and dry biomass weight of weeds and corn. The data was analyzed descriptively and comparatively by calculating density, frequency, and dominance to obtain an important value index and summation diminance ratio (SDR). The results of the research showed that 14 species of broad-leaved weeds were found with high species diversity, distribution, dominance, and abundance indices. The competitiveness and relative weighted dominance of six weed species, namely Amaranthus spinusus, Amaranthus gracilis, Synedrella nodiliflora, Acalypha indica, Ageratum conyzoides, and Alternanthera philoxeroides, are higher than those of other weed species, causing corn yield losses of 5.56%–21.90%. Therefore, these six weed species must be controlled.
This review covers recent developments and trends in herbicide-resistant (HR) weed management in agronomic field crops. In countries where input-intensive agriculture is practiced, these developments and trends over the past decade include renewed efforts by the agrichemical industry in herbicide discovery, cultivation of crops with combined (stacked) HR traits, increasing reliance on preemergence vs. postemergence herbicides, breeding for weed-competitive crop cultivars, expansion of harvest weed seed control practices, and advances in site-specific or precision weed management. The unifying framework or strategy underlying these developments and trends is mitigation of viable weed seeds into the soil seed bank and maintaining low weed seed banks to minimize population proliferation, evolution of resistance to additional herbicidal sites of action, and spread. A key question going forward is: how much weed control is enough to consistently achieve the goal of low weed seed banks? The vision for future HR weed management programs must be sustained crop production and profitability with reduced herbicide (particularly glyphosate) dependency.
Polyethylene (PE) mulch and biodegradable plastic mulches (BDMs) have been used in annual vegetable and strawberry (Fragaria × ananassa Duch.) production systems for several decades due to their ability to suppress weeds, modify soil temperature and moisture, and promote earlier and greater yields. However, there are only a few studies that have explored mulch use in perennial production systems. The overall objective of this study was to compare PE mulch and BDMs to growers’ standard practice of bare ground (BG) cultivation in a floricane red raspberry (Rubus idaeus L.) production system in northwestern Washington, USA. Cumulative weed growth, root lesion nematode [Pratylenchus penetrans (Cobb) Filipjev and Schuurmans Stekhoven; RLN] population densities, soil temperature and moisture, cumulative plant growth, and fruit yield were evaluated in a ‘Wake ™ Field’ red raspberry field in 2017 and 2018. Compared to the BG control, PE mulch and BDMs suppressed weeds and generally increased soil temperature. Root lesion nematode population densities were greater in soil covered with PE mulch than Novamont 0.5, and were greater in raspberry roots from plots treated with PE mulch than BASF 0.6 and the BG control. Primocane height and number were higher for plants grown with mulches relative to the BG control in 2017. Average fruit yield of plants from the mulched treatments was 34% greater than the BG control. Overall, this research demonstrated that PE mulch and BDMs improved raspberry plant growth and yield. These findings demonstrate the potential benefits of using PE mulch and BDMs for improving establishment in perennial crops.
Core Ideas
Air‐propelled corncob grit can control in‐row weeds in corn through abrasion
A single grit application applied at V1 or V3 of corn increased silage yield.
A single grit application applied at V5 or V7 suppressed weeds, but had lower silage yield.
Weed management in organic farming requires many strategies to accomplish acceptable control and maintain crop yields. This 2‐yr field study used air propelled abrasive grit for in‐row weed control in organically certified silage corn ( Zea mays L.). Corncob grit was applied as a single application at corn vegetative growth stages V1 (one true leaf; numbers correspond to number of true leaves at the corn vegetative stage), V3, or V5 (in 2013) and V3, V5, and V7 (in 2014) and in double and triple combinations at these stages. Between‐row weed control was accomplished by flaming or cultivation after the last grit application. Grit effects on weed efficacy and silage yield were quantified and compared with hand‐weeded and season‐long weedy treatments. Grit applications decreased in‐row weed biomass by >80% and increased yield up to 250% when compared with the weedy check. Single early applications (V1 and V3) increased yield, with additional treatments decreasing end‐of‐season weed density and biomass. Single late grit applications (V5 and V7) also decreased weed biomass, but silage yields were reduced compared with hand‐weeded and early treatments. Early grit applications may have value for growers to control in‐row annual weeds in organic silage corn without soil disturbance.
Weed control is challenging to farmers who are transitioning from production systems that use synthetic herbicides to organic systems. A 2-year field study examined air-propelled corncob grit abrasion for in-row weed control efficacy and effect on corn yield. Grit was applied based on corn vegetative developmental stages with one (V1, V3 or V5), two (V1 + V3, V1 + V5, or V3 + V5), or three (V1 + V3 + V5) applications. Flame-weeding or cultivation was used after the V5 application for between-row weed control. Grit applications decreased in-row weed densities by about 60% (α = 0.05) and biomass up to 95% (α = 0.001). Between-row treatments provided similar control, and reduced weed biomass by 55% in 2013 (α = 0.01) and 86% (α = 0.001) in 2014. In-row grit treatments increased corn yield up to 44%, and yield was more influenced by in-row weeds than between row weeds. These results indicate that abrasive corncob grit for in-row weed control, supplemented with cultivation or flaming, can reduce weed biomass substantially and help maintain corn yield. However, timing and frequency of grit application need further refinement based on weed growth as influenced by climate, as treatments at similar corn growth stages did not consistently provide adequate weed control between years.
Corn gluten meal (CGM) is an approved organic fertilizer and pre-emergence herbicide that can be manufactured in the form of grit. This grit was tested for its ability to abrade seedlings of the summer annual weedy grass, Setaria pumila, when plants were in the 1- to 5-leaf stages of growth. CGM was propelled at air pressures of 250–750 kPa at distances of 30–60 cm from the plants. Established seedlings of S. pumila were controlled more effectively when grit was applied at 500 and 750 kPa than at 250 kPa, as well as when the applicator's nozzle was 30 cm from the plants compared to 60 cm distance. Seedling growth and dry weights were greatly reduced by exposures to grit at 60 cm and 500 kPa for 2 s or less, and seedlings were nearly completely destroyed at 30 cm distance and 750 kPa. CGM, a soft grit, was as effective for abrading seedlings as fine quartz sand, a hard grit. CGM had little pre-emergence herbicidal effect on S. pumila. Although regrowth can occur in S. pumila after abrasion by grit, the initial grit-induced stunting is sufficient to allow competing crop plants, like maize, to escape competition and suppress the weed. Consequently, CGM may be an effective form of soft grit for post-emergence abrasion of seedlings of summer annual grass weeds in organic row crops, while simultaneously supplying the crop with fertilizer.
Weeds are a top management concern among organic vegetable growers. Abrasive weeding is a nonchemical tactic using air-propelled abrasive grit to destroy weed seedlings within crop rows. Many grit types are effective, but if organic fertilizers are used, this could integrate weed and nutrient management in a single field pass. Our objective was to quantify the effects of abrasive grit and mulch type on weed suppression, disease severity, soil nitrogen availability, and yield of pepper ( Capsicum annuum L. ‘Carmen’). A 2-year experiment was conducted in organic red sweet pepper at Urbana, IL, with four replicates of five abrasive grit treatments (walnut shell grits, soybean meal fertilizer, composted turkey litter fertilizer, a weedy control, and a weed-free control) and four mulch treatments (straw mulch, bioplastic film, polyethylene plastic film, and a bare soil control). Abrasive weeding, regardless of grit type, paired with bioplastic or polyethylene plastic mulch reduced in-row weed density (67 and 87%, respectively) and biomass (81 and 84%); however there was no significant benefit when paired with straw mulch or bare ground. Despite the addition of 6 to 34 kg N/ha/yr through the application of soybean meal and composted turkey litter grits, simulated plant N uptake was most influenced by mulch composition (e.g., plastic vs. straw) and weed abundance. Nitrogen immobilization in straw mulch plots reduced leaf greenness, plant height, and yield. Bacterial spot ( Xanthomonas campestris pv. Vesicatoria ) was confirmed on peppers in both years, but abrasive weeding did not increase severity of the disease. Pepper yield was always greatest in the weed-free control and lowest in straw mulch and bare soil, but the combination of abrasive weeding (regardless of grit type) and bioplastic or polyethylene plastic mulch increased marketable yield by 47% and 21%, respectively, compared with the weedy control. Overall, results demonstrate that when abrasive weeding is paired with bioplastic or polyethylene mulch, growers can concurrently suppress weeds and increase crop N uptake for greater yields.
Weeds, pests and diseases in Rubus plantations can have significant economic impact through their negative effects on yield and the costs of implementing control measures. Yield losses can be particularly high for certain pests and diseases, in some cases leading to total plantation losses. While the costs of weed control are rarely quantified, weeds can be a major detriment to profit in Rubus and other perennial fruit production systems. Although chemical control methods can be effective, growers are under increasing pressure to produce fruit sustainably with reduced chemical inputs to mitigate health risks and environmental damage (e.g. Łozowicka et al. 2012). In Europe, this has led to the requirement for each EU Member State to implement a National Action Plan with Integrated Pest Management (IPM; where the term ‘pest’ covers all injurious biotic stressors attacking crop plants) as a central crop protection strategy. Agroecological approaches offer an opportunity to develop sustainable weed, pest and disease management interventions by developing an understanding of the system processes and functions contributing to pest and disease regulation (Birch et al. 2011; Kremen et al. 2012). A framework for adopting an agroecological approach to promote integrated pest and disease management is provided by Birch et al. (2011) and includes (i) use of pest-resistant cultivars, (ii) optimising synthetic pesticide and biopesticide applications, (iii) use of bioactive substances (e.g. pheromones, semiochemicals), (iv) enhancing biocontrol using natural enemies, and (v) ecological engineering of habitats and landscapes to optimise pest and disease suppression. This chapter reports on recent progress and available options for these management measures in Rubus plantations.
Non-chemical control of weeds is essential for organic farming and is a potential solution to address herbicide-resistant weeds, but too few non-chemical control methods exist. Consumers, farmers, and regulators want organic produce, new tools, and fewer xenobiotics. New weed management strategies focused on the integration of different tools, and strategies are needed to minimize dependence on broad-spectrum herbicides. Accordingly, we assessed abrasive grits from eight agricultural sources (almond shell, grape seed, maize cob, olive seed, poultry manure, sand, soybean meal, and walnut shell) as weed-abrading materials when delivered at high air pressures. Grit efficacies were determined in laboratory trials on weeds common to tomato, sugar beet, and olive: Amaranthus retroflexus L., Chenopodium murale L., and Centaurea cyanus L., respectively. Additionally, application rates and costs of residues were estimated. Control of two- to three-leaf stage weed seedlings ranged from 30 to 100%. In 88% of the trials, weed control exceeded 80%. Except for sand, the effectiveness of the grits was not species dependent. Significant differences in the mass flow of grits suggested that effective doses may vary up to 100% among grit materials. The residue yield ratio (percent control per gram of grit) varied among residues, ranging from 2.8 to 7.1% g⁻¹. We demonstrate that the best combination of weed control, grit dose, and residue yield ratio was provided by maize cob and olive seed, with control rates of 93 and 90%, respectively. This pioneering study simultaneously assessed residues from both herbaceous and woody crops as well as animal wastes and indicated that a more efficient and effective use of these resources for weed control is feasible.
New techniques are needed to control quackgrass in organic crops. With ≥2 applications of abrasive air-propelled (800 kPa) corncob grit to 15-cm-tall quackgrass tillers, regrowth was minimal at 5 wk after treatment. Abrasive grits may be effective tools to help manage perennial weeds in organic row crops.
Spent coffee grounds (SCG) represent a significant food waste residue. Value-added uses for this material would be beneficial. Gritty agricultural residues, such as corncob grit, can be employed as abrasive air-propelled agents for organically-compatible and selective shredding of weed seedlings within established crops. SCG were tested and compared with corncob grit for their ability to injure seedlings of two important weeds: waterhemp and velvetleaf. Waterhemp seedlings were controlled completely with as little as 0.5 g of SCG at an air pressure of 690 kPa. Velvetleaf seedlings were much larger than those of waterhemp at the time of grit application, better tolerated SCG abrasion, but still were damaged appreciably by 1 to 2 g of grit. SCG were at least as effective for abrading weed seedlings as corncob grit, whose value for this purpose in organic crops was demonstrated previously. Nomenclature: Tall waterhemp, Amaranthus tuberculatus (Moq.) Sauer; velvetleaf, Abutilon theophrasti Medik.
Weed management is key component of establishing and sustaining a profitable organic orchard. Good site preparation is a critical part of an orchard establishment plan. Pre-plant weed control coupled with addressing soil fertility issues before planting can dramatically increase the options available to producer for weed management, while reducing the time to commercially viable levels of fruiting and harvest. Tillage may be the best option on sites with perennial rhizomatous weeds and low soil fertility, or where there is high risk of rodent damage to the crop. Dead organic mulches are best suited to sites with low presence of perennial rhizomatous weeds and sites where at least moderate levels of soil fertility are present. While living mulches tend to provide a desirable habitat in the orchard understory, they are competitive with the crop for water and nutrients, regardless of whether they are mowed or not. They should only be used on sites with good background soil fertility, with frequent mowing, and where climate or irrigation minimize risk of moisture stress. Most manufactured mulches can provide effective weed control for a longer period of time but reduce soil fertility management options. The use of biodegradable mulches under dead organic mulches poses interesting possibilities and should be studied further. Organic herbicides are presently not effective enough or too costly to be used as the primary means of weed control but would be a useful tool for spot and edge control of weeds in mulches.
Abrasive-weeding is a novel weed management tactic with potential to reduce tillage and hand-weeding in organic agriculture. However, abrasive-weeding has not been tested in vegetable cropping systems and growers are interested in the potential for using organic fertilizers as abrasive grits to control weeds and supplement crop nutrition in one field pass. A two-year field study was conducted at the University of Illinois Sustainable Student Farm to determine the effect of air-propelled abrasive grit type, including organic fertilizers, and application frequency on weed density and biomass and crop yield and marketability in organic tomato (Solanum lycopersicum L.) and pepper (Capsicum annuum L.) cropping systems. Abrasive-grits, including granulated walnuts shells and maize cobs, greensand fertilizer, and soybean meal, were applied via compressed air between one and four times within planting holes of plastic mulch. Weed density was quantified 25 or 37 days after the first application and weed biomass was harvested at the end of the growing season. Tomatoes and peppers were harvested ripe and graded for marketability. Two applications of abrasive grits, regardless of grit type, reduced weed density by 63% and 80% in tomato and pepper, respectively. Broadleaf weeds were more susceptible to abrasive-weeding than grass weeds. Abrasive-weeding reduced final weed biomass by 69-97% compared with the weedy control, regardless of grit type or application frequency. Total tomato yield was up to 44% greater in treated plots compared with the weedy control, whereas total yield gains in pepper (up to 33%) were only approaching significance (p = 0.09). Yield and the marketability of fruit was not negatively affected by grit application, despite minor stem and leaf tissue damage after applications. Organic fertilizers used as abrasive grits in this study could contribute between 35 and 105 kg N ha-1, which may improve the functionality and economic feasibility of abrasive-weeding.
Abrasive weed control is a novel weed management tactic that has great potential to increase the profitability and sustainability of organic vegetable cropping systems. The objective of this study was to determine the effect of air-propelled organic abrasive grits (e.g., organic fertilizers) on weed seedling emergence and growth and vegetable crop growth. A series of thirteen greenhouse trials were conducted to determine the susceptibility of weeds to abrasive weed control with one of six organic materials including: corn cob grits, corn gluten meal, greensand fertilizer, walnut shell grits, soybean meal, and bone meal fertilizer. In addition, crop injury was quantified to determine the potential utility of each organic material as abrasive grits in tomato and pepper cropping systems. Of the six organic materials, corn gluten meal, greensand fertilizer, walnut shell grits, and soybean meal provided the broadest range of POST weed control. For example, one blast of corn gluten meal and greensand fertilizer reduced Palmer amaranth (one-leaf stage) seedling biomass by 95 and 100% and green foxtail (one-leaf stage) biomass by 94 and 87%, respectively. None of the organic materials suppressed weed seedling emergence when applied to the soil surface, suggesting that residual weed control with abrasive grits is unlikely. Tomato and pepper stems were relatively tolerant of abrasive grit applications, though blasting with select materials did increase stem curvature in tomato and reduced biomass (corn cob grit) and relative growth rate (corn gluten meal and greensand) in pepper. Results suggest that organic fertilizers can be effectively used as abrasive grits in vegetable crops, simultaneously providing weed suppression and supplemental crop nutrition. Field studies are needed to identify cultural practices that will increase the profitability of multifunctional abrasive weed control in organic specialty crops.
A potential new post-emergence physical weed control tactic is described. It entails plant abrasion and death upon assault from abrasive grits propelled by compressed air. Grit derived from granulated walnut shells was delivered by a sand blaster at 517 kPa at distances of 300-600 mm from seedlings of Chenopodium album in glasshouse pots. Control was influenced by size of plants at time of treatment. Seedlings at the cotyledon to 2-leaf stages of growth were mostly destroyed by a single split-second blast of grit of <1 s duration, but were unaltered by compressed air alone. Plants at the 4- to 6-leaf growth stages required up to 10 blasts of grit to be killed. These results indicate that small weed seedlings of susceptible species might be physically controlled by abrasion from air-propelled grit derived from suitable agricultural residues.
Pacific Northwest Weed Management Handbook
- E Peachey
Commercial Red Raspberry Production in the Pacific Northwest
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