Project Number: 6402-22000-045-03
Project Type: Specific Cooperative Agreement

Start Date: Jul 09, 2002
End Date: Jul 08, 2007

Objective:
Research will be established to demonstrate weed control, sweetpotato injury, and sweetpotato grade yield to sweetpotato producers in Bolivar Co., MS. Treatments will include herbicides that are currently labeled for use in sweetpotato and others, which will include old and new chemistry that is not currently labeled. It is necessary to evaluate new herbicides since the weed spectrum in the delta is different compared to upland soils typically used for sweetpotato production in Mississippi. In addition, other means of weed management currently used by delta sweetpotato producers, such as use of a rotary mower will be included for treatment comparison. The objective of this research is to demonstrate appropriate herbicide systems by illustrating herbicides applied alone or with a tank-mix partner, application timings, and herbicide rates.

Approach:
The trial will be established on soil with weed species typically present in sweetpotato production fields in the delta of Mississippi. Common production practicies may include transplanting Beauregard sweetpotato slips into a conventional seedbed by the appropriate date as stated by crop insurance guidelines. Planting rate will be at leat 1 plant per 14-in on 40-in rows. Pre-plant fertilizer will be applied at a rate of 40-60-120 lb ac of N, P, and K or according to soil test recommendations. The experiment design will be a randomized complete block with 4 replications. Plots will be 10' x 30' in size or some factor relevant to available equipment spacing. Treatments could include flufenacet (Define), flufenacet plus metribuzin (Axiom), metolachor (Dual), clomazone (Command), fluazifop (Fusilade), and halosulfuron (Sandea). Herbicides may be applied at 1x and 2x rates to sweetpotato at postemergence (POST) immediately following transplant and POST at 3 weeks after transplant (WAT). Treatments will be applied using a CO2 backpack sprayer with a 2-man boom. Visual estimated weed control and plant injury will be rated on a scale of 0 to 100%, where )=no control or 100=complete plant growth termination. Visual observations will be made at 3, 4, and 6 weeks after transplant (WAT). The center row of each plot will be harvested and weetpotato grade will be determined for US No. 1, Canners, Culls, and Jumbo yield. Total marketable yield will be recorded as the sum of US No., Canners, and jumbo grade yields. Statistical analysis will be conducted and means will be separated using Fishers protected LSD (a=0.05).