Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2003
Publication Date: August 1, 2003
Citation: TAKEDA, F., GLENN, D.M., TWORKOSKI, T. SOIL AMENDMENT WITH HYDROPHOBIC KAOLIN PARTICLES REDUCE WEEDS. HORTSCIENCE. 2003. 38:659 Technical Abstract: Experiments were performed to suppress weed seed germination by amending soil surface layer with a hydrophobic kaolin particle (M96-018, Engelhard Corp.). In the first study, a field that was in permanent pasture the previous 5 years was rototilled. After rototilling, 1-m2 plots of untreated and treated soil were established in a pair-t-test design with 6 replications. In the treated soil, M96-018 was incorporated uniformly into the upper 3-cm of soil with hand cultivation in August 1996. The concentration of M96-018 was 3% by weight and 20% by volume in the treated soil. Following spring, a circular area of 1,195 cm2 was sampled in the center of each plot. Dry mass of vegetation in the untreated treatment was 218.5 g/m2 and was significantly higher (p=0.05) than the 23.5 g/m2 harvested from the treated soil. In the second experiment, 'Apache' blackberry container plants were planted through 900-cm2 square openings spaced 75 cm apart in woven fabric weed barrier covering a raised bed. The square openings were either mulched with a 2- or 4-cm layer of M96-018 (5% hydrophobic kaolin particle in dry field soil by volume) or treated post-plant with napropamide (Devrinol 50 DP at 4 lb/100 gal). The other two treatments in this study consisted of mechanical weeding at 2-week intervals and untreated control. At monthly intervals during the growing season, weed coverage was determined and weed species were identified, counted, and removed. The following weeds were dominant: crabgrass, lambsquarter, and nightshade. By end of July, untreated plots had 100% weed cover while mechanical weeding plots had the following soil surface area covered with weeds: 74% in June, 27% in July, and 10% in August. In plots treated with napropamide or mulched with 5% hydrophobic kaolin only 15 and 3 weed seedlings were pulled during the establishment year. These data showed that when soil is amended with hydrophobic particles, seed germination in the amended zone is greatly inhibited due to reduced availability of water in the amended zone. Seed germination may occur at the amended soil-natural soil interface and some weed species have the capacity to grow through a shallow, but not deep layer of soil amended with hydrophobic kaolin particle. Effects of kaolin soil amendment on blackberry growth will be discussed.