|PEREZ-RUIZ, MANUEL - University Of Sevilla
|BRENES, R - University Of Sevilla
|URBANO, JOSE - University Of Sevilla
|SLAUGHTER, DAVID - University Of California
|RODIGUEZ-LIZANA, A - University Of Sevilla
Submitted to: Agronomy for Sustainable Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2018
Publication Date: 3/21/2018
Publication URL: http://handle.nal.usda.gov/10113/5918122
Citation: Perez-Ruiz, M., Brenes, R., Urbano, J.M., Slaughter, D.C., Forcella, F., Rodiguez-Lizana, A. 2018. Agricultural residues are efficient abrasive tools for weed control. Agronomy for Sustainable Development. 38:18. https://www.doi.org/10.1007/s13593-018-0494-6.
Interpretive Summary: One of the greatest agronomic hurdles for organic growers is weed control. New techniques for weed control are desirable, especially ones that do not involve soil disturbance. A new technique involves abrading weed seedlings within crop rows by air-propelled grit. The grits often are comprised of agricultural residues or waste products, and putting these grits to use for weed control may add to their value. However, the characteristics that define effective grits for weed control are unknown. Consequently, we examined eight gritty agricultural materials (almond shell, corn cob, grape seed, olive seed, poultry manure, sand, soybean seed meal, and walnut shell) for their abilities to injure weed seedlings and their distinguishing physical/engineering characteristics. The best combination among weed injury, applied dose and residue yield ratio was obtained with corn cob and olive seed grits, with control rates of 93% and 90%, respectively. These results reveal potential new uses for materials that often are considered as wastes, thus allowing a more efficient use and a better consumption of available resources. This information is of value to agricultural engineers, weed scientists, extension educators, organic growers, and others interested in new forms of weed control in organic crops.
Technical Abstract: Non-chemical control of weeds is one of the most important needs of organic agricultural production and, ironically, herbicide resistant crops. There is a knowledge gap regarding alternative control methods that reduce the use of herbicides. This need for alternatives is motivated by increased consumer demand for organic produce, consumer and regulatory demands for reductions in environmentally harmful herbicide use, and a steady rise in weeds with multi-herbicide resistance. The objective of this study was to assess grits from eight agricultural materials (almond shell, grape seed, maize cob, olive seed, poultry manure, sand, soybean seed meal, and walnut shell) as weed-abrading materials delivered at high pressures through condensed-air machinery. Most of these materials typically are considered as agricultural wastes. Laboratory trials were conducted to determine the efficacies of these grits when applied to common weeds in simulated fields or orchards of tomato, sugar beet and olive. These weeds were Amaranthus retroflexus L., Chenopodium murale L. and Centaurea cyanus L. In addition, application rates and the cost of the residues also were assessed. Control of 3-leaf stage weed seedlings ranged between 30% and 100%. In 88% of the trials, control exceeded 80%. With the exception of sand, the effectiveness of the residues did not depend on the species of weed being treated. Significant differences in the mass flow of residues (p <0.10) also were obtained, implying variations of up to 100% in the effective doses among residues. The residue yield ratio, which was selected as an estimator of the efficacy of the application, varied among residues, ranging from 2.8 to 7.1% per gram. Our results allow us to affirm that the best combination among weed control, applied dose and residue yield ratio corresponded to maize cob and olive seed, with control rates of 93% and 90%, respectively. This is the first study that simultaneously assessed residues from both herbaceous and woody crops, as well as animal wastes, in an effort to generalize the technique. The study of these materials can provide new uses for materials that often are considered simply as wastes; thus, allowing a more efficient use and a better consumption of these resources.