Cultivation is a proven means of weed control in organic peanut. However, weeds present in-row often escape control. Research trials were conducted in Ty Ty, GA to modify cultural practices to help suppress weed emergence in-row. Modified cultural practices were three row pattern/seeding rate combinations; twin rows (four rows on a seedbed) seeded at the recommended (1X) seeding rate that produced 13 seed m−1 in each row, twin rows seeded at the 2X seeding rate that produced 23 seed m−1 in each row, and wide rows (two rows on seedbed) seeded at the recommended seeding rate that produced 23 seed m−1. Four cultivation regimes were evaluated; cultivation with a tine weeder at weekly intervals for 6 wk, cultivation with a tine weeder at weekly intervals for 8 wk, scouring with a brush hoe at vegetative emergence followed by the tine weeder for 6 wk, and a noncultivated control. There were no interactions between row pattern/seeding rates and cultivation regimes for any parameter measured. There was inconsistent response of weed control and peanut yield to row pattern/seeding rates. Weed control and peanut yields were similar with tine weeding for 6 wk, 8 wk, or with the brush hoe followed by the tine weeder. Weed management in organic peanut was not improved by altering peanut cultural practices that facilitate quicker canopy closure, and the use of narrow row patterns should not be based on attempts to improve weed control in organic peanut. Narrow row patterns provide other benefits to organic peanut production and those attributes should influence decisions on the choice of row pattern, not weed control.

Weed control in organic peanut production is difficult and costly. Sweep cultivation in the row middles is effective, but weeds remain in the crop row, causing yield loss. Research trials were conducted in Ty Ty, GA to evaluate implements and frequencies of cultivation to improve in-row weed control in organic peanut. Implements were a tine weeder and power takeoff-powered brush hoe that targeted weeds present in the row. Frequencies of cultivation were at vegetative emergence of peanut (VE), 1 wk after VE (1wk), 2 wk after VE (2wk), sequential combinations of VE/1wk, VE/2wk, and VE/1wk/2wk. All plots were cultivated with a sweep cultivator to control weeds in row middles. The tine weeder tended to be easier to operate and performed more consistently than the brush hoe. Both implements performed best when initial cultivation was at VE. Delaying the initial cultivation reduced overall effectiveness. Plots with the best in-row weed control were hand-weeded once to control escapes and harvested for peanut yield. The best overall combination of weed control, minimal use of salvage hand-weeding, and maximum peanut yield resulted from sequential cultivation at VE/1wk using either the tine weeder or brush hoe, row middle sweep cultivation, and preharvest mowing.

Weed control in organic peanut is difficult and lack of residual weed control complicates weed management efforts. Weed management systems using corn gluten meal in combination with clove oil and sweep cultivation were evaluated in a series of irrigated field trials. Corn gluten meal applied in a 30 cm band over the row at PRE, sequentially at PRE+2 wk after emergence, and PRE+2wk+4wk did not adequately control annual grasses and smallflower morningglory. Similarly, a banded application of clove oil applied POST did not adequately control weeds. The only treatment that improved overall weed control was sweep cultivation. Peanut yields were not measured in 2006 due to heavy baseline weed densities and overall poor weed control. Peanut yields were measured in 2007 and were not affected by any weed control treatment due to poor efficacy. While sweep cultivation improved weed control, weeds were controlled only in the row middles and surviving weeds in-row reduced peanut yield. Even when used in combination with sweep cultivation, corn gluten meal and clove oil were ineffective and offer little potential in a weed management system for organic peanut production.

Cantaloupe and watermelon growers in the southeastern United States use a system of hybrid transplants grown on narrow low-density polyethylene (LDPE) mulch-covered seedbeds with overhead irrigation and use the mulch cover for only one crop. LDPE mulches are costly to remove from the field and dispose. Biodegradable mulches that eliminate removal and disposal costs would be of significant benefit, provided that weeds are adequately suppressed. Cotton gin trash is a biodegradable waste product, composed of fiber fragments and seed pieces. Using a proprietary process, cotton gin trash can be chopped, pressed, and heated into a loose mat and stored on a continuous roll. Preliminary studies were conducted in 2010 and 2011 to determine if rolled cotton fiber mulch made from gin trash could be applied as a seedbed cover using conventional application equipment and adequately suppress weeds. Mulching materials (rolls 91 cm wide) were applied with a mulch layer that produced a finished seedbed 40 cm wide. ‘Athena' cantaloupe and ‘Crimson Sweet' watermelon were transplanted using a waterwheel transplanter. Mulching materials included rolled cotton fiber mulch sprayed with boiled linseed oil after mulch application, rolled cotton fiber mulch sprayed with black latex paint, black LDPE, and bare ground. Herbicide treatments included ethalfluralin, halosulfuron, and glyphosate applied as directed spray and nontreated with herbicides. Rolled cotton fiber mulch was easily applied with a conventional mulch layer with no modification and minimal adjustment, producing no tears or holes. Biodegradable cotton fiber mulch treated with boiled linseed oil or black latex paint suppressed weeds equally well as LDPE and all were better than bare-ground plots. Herbicides improved control of all weeds over the nontreated control and this effect was independent of weed suppression provided by seedbed mulches. Cantaloupe and watermelon yields were not affected by seedbed mulches, but were increased by weed control provided by herbicides.