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Spent Coffee Grounds as Air-Propelled Abrasive Grit for Weed Control in Organic Production
Abstract
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.
... In another experiment, lettuce and cucumber cultivated with organic coffee ground amendments showed better quality parameters compared to other fertilizer combinations [37][38][39]. Moreover, spent coffee grounds (SCGs) represent a significant food waste residue, which could be used for weed control in organic agriculture [40]. An experiment with coffee grounds showed that water extract did not inhibit the growth of phytopathogenic fungi or foodborne pathogenic bacteria. ...
Coffee is a beverage that contains a high concentration of bioactive compounds, particularly polyphenols. These compounds significantly contribute to the polyphenol intake in the diet and have been shown to have beneficial effects on consumer health. The objective of this research was to conduct a comparative analysis of the polyphenolic composition of coffee beans and infusions obtained from coffee beans sourced from both organic and conventional farming practices while taking into consideration variations in roast intensity and geographical origin. The lyophilized coffee grounds and infusions derived from these grounds were also subjected to analysis. The antioxidant activity was measured by using the radical ABTS, and the quantitative and qualitative analysis of polyphenolic compounds was conducted by HPLC. The conventional coffee samples were richer in chlorogenic acid, catechin, and caffeic acid. However, the coffee beans from organic farming contained more gallic acid, epigallocatechin gallate, and quercetin than those grown conventionally. We did not observe significant differences among the coffee plant production sites in Ethiopia, Sumatra, and Peru, but Peru had the poorest amount of polyphenols when compared to Ethiopia and Sumatra. Coffee infusions prepared from organic coffee beans were characterized by a significantly high sum of identified polyphenols. A higher content of caffeine was observed in the organic coffee bean samples than in the conventional coffee bean samples. Conventional coffee beans were characterized by stronger antioxidant activity than organic beans. Coffees from different parts of the world were characterized by different profiles of polyphenol compounds. Moreover, the coffee beans from Ethiopia were characterized by the highest caffeine content. However, among the different geographical areas of coffee beans, the highest antioxidant activity was detected in the coffee beans from Sumatra. Coffee grounds also have the potential to be used as compounds for the cultivation of horticultural plants, and they can be used as a source of numerous health-promoting compounds in the food and cosmetics industries.
... Renewable Agriculture and Food Systems 5 of grit. These include grits derived from those mentioned above as well as corn cobs, grape pomace, pelleted organic fertilizers, spent coffee grounds, and walnut shells (Forcella, James and Rahman, 2010;Forcella, 2017;Perez-Ruiz et al., 2018;Carlson et al., 2020). Use of such agricultural residues as weed-stunting abrasive grits converts burdens into value-added products and economic opportunities. ...
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.
For decades, herbicides have provided easy-to-use, cost-effective weed management, but alternatives are desired. Consumer preference for chemical-free food, awareness of environmental impacts, regulation increasingly restricting agrichemical use, and increasing prevalence of herbicide resistance are forcing changes to weed management strategies.
New Zealand farming must remain sustainable and profitable while responding to changes in its overseas markets, among which are increasing demands for regeneratively grown, safe, high-quality produce. Current reliance on herbicides should be reduced, with more emphasis on preventative management by cultural means, and weed suppression by alternative technologies.
The emergence of agritechnologies incorporating automation, machine vision and artificial intelligence, and development of new techniques for weed destruction, offer alternatives that minimise or avoid the requirement for herbicides, avoid soil disturbance and can work effectively in high crop or crop-residue conditions.
We have identified electric weeding as a feasible alternative and pulsed electric microshocks as a very low-energy option requiring a fraction of the energy of any other system. Pulsed microshocks enable an integrated weed management system for vegetable and arable crop production combining cultural controls and inexpensive pre-planting treatments with automated application of chemical-free in-crop weed control. Open-source software enables community development of autonomous deployment for niche crops.
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.
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.
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.
This study presents the complete utilization of spent coffee grounds to produce biodiesel, bio-oil, and biochar. Lipids extracted from spent grounds were converted to biodiesel. The neat biodiesel and blended (B5 and B20) fuel properties were evaluated against ASTM and EN standards. Although neat biodiesel displayed high viscosity, moisture, sulfur, and poor oxidative stability, B5 and B20 met ASTM blend specifications. Slow pyrolysis of defatted coffee grounds was performed to generate bio-oil and biochar as valuable co-products. The effect of feedstock defatting was assessed through bio-oil analyses including elemental and functional group composition, compound identification, and molecular weight and boiling point distributions. Feedstock defatting reduced pyrolysis bio-oil yields, energy density, and aliphatic functionality, while increasing the number of low-boiling oxygenates. The high bio-oil heteroatom content will likely require upgrading. Additionally, biochar derived from spent and defatted grounds were analyzed for their physicochemical properties. Both biochars displayed similar surface area and elemental constituents. Application of biochar with fertilizer enhanced sorghum–sudangrass yields over 2-fold, indicating the potential of biochar as a soil amendment.
The objective of this paper is to discuss the use of coffee grounds in the Brazilian soluble coffee industry. This residue is used as a fuel in the boilers of the same industry; so, data about their utilization are presented and analysed, discussing the actual technology and the advantages of improving the drying of the biomass with the exhaust combustion gases. After that, an experimental study is reported on the characteristics of this material, which are important for the combustion process, including the transport, storage and drying, the mean diameter of the particles, talus angle, apparent and real density, sphericity, surface area, terminal velocity, spontaneous ignition temperature and heat of combustion.
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.
Design and Analysis of a New Abrasive Blasting System Utilized in a Novel Weed Control Method. MS thesis
- C M Lanoue