Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 29, 2004
Publication Date: June 1, 2005
Citation: Takeda, F., Glenn, D.M., Tworkoski, T. 2005. New strategies for weed control in blackberry plantings. Hortscience. Vol 40(3): 714-719. Interpretive Summary: Weeds must be controlled especially during the first two months following blackberry establishment, or weeds will compete with blackberry plants for water and nutrients and adversely effect plant productivity. We conducted studies to evaluate hydrophobic kaolin mulch and sprayable oil-based kaolin material, along with two herbicides (napropamide and Bio-Weed®) and for their potential to suppress weeds and to determine the effect of these products on subsequent blackberry plant growth and yield. Weed control was achieved with hand-weeding, napropamide, and 4-cm deposition of hydrophobic mulch around the blackberry plant and blackberry growth in year 1 and 2 and fruit production in year 3 were significantly greater for plants that grew without weed competition than plants that grew in weedy plots in year 1. The sprayable oil-based kaolin was effective in preventing weeds establishment but it also killed newly planted blackberry plants. This study demonstrated that several different approaches provided acceptable weed control for field establishment of blackberry transplants. Our kaolin products could be added to the arsenal of tools for managing weeds in horticultural crops.
Technical Abstract: Three experiments were performed to determine the effect of amending the soil surface layer and mulching with hydrophobic kaolin particle on weeds and blackberry (Rubus subgenus Rubus Watson) plants. In the first study a processed kaolin material (Product No. M-96-018, Engelhard Corporation, Iselin, N.J.) was incorporated in August into the top 3 cm of freshly roto-tilled field that had been in pasture the previous 5 years. The following spring, dry weight of vegetation in the control treatment was 219 g/m2 and was significantly higher (P = 0.05) than the 24 g/m2 harvested from the treated soil. In two other studies, planting holes for blackberry transplants were either pre- or post-plant mulched with a 2- or 4-cm layer of 5 or 10% hydrophobic kaolin in field soil (w/w), post-plant treated with napropamide, corn gluten meal, a product comprised of hydrous kaolin, cotton seed oil, and calcium chloride in water (KOL), hand weeded, or left untreated. Although untreated plots had 100% weed cover by end of July, herbicide treatments, 4-cm deposition of hydrophobic kaolin particle/soil mulch, and KOL suppressed weeds the entire establishment year. Pre-plant application of hydrophobic kaolin mulch and post-plant application of KOL reduced blackberry growth and killed transplants, respectively. In Year 2, blackberry plants produced more primocanes that were on average 10-cm taller in weed-free plots (herbicide, 4-cm kaolin soil mulch, and mechanical weeding) than in weedy plots (control and 2-cm kaolin soil mulch). In Year 3, yield was significantly lower in control plots (1.5 kg/plant) than in plots that were treated with napropamide and 2- and 4-cm hydrophobic kaolin mulch, or hand weeded during the establishment year (4 kg/plant). The results showed that 4 cm hydrophobic kaolin mulch applied after planting can suppress weeds without affecting blackberry productivity. These kaolin products are excellent additions to the arsenal of tools for managing weeds in horticultural crops.