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ARS Home » Southeast Area » Dawson, Georgia » National Peanut Research Laboratory » Research » Publications at this Location » Publication #221061
Title: Weed Control Systems for Peanut Grown as a Biofuel Feedstock

Author
item Faircloth, Wilson
item FERRELL, JASON - UNIV. OF FLA
item MAIN, CHRIS - UNIV. OF FLA

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/22/2007
Publication Date: 6/1/2007
Citation: Faircloth, W.H., Ferrell, J., Main, C. 2007. Weed Control Systems for Peanut Grown as a Biofuel Feedstock. Proceedings of Southern Weed Science Society.

Interpretive Summary: not required.

Technical Abstract: Alternative fuels such as biodiesel provide a cost effective and environmentally friendly solution to rising fuel costs. While soybean is the primary oilseed used in biodiesel production, it contains only 18 - 25% oil in comparison to peanut kernels that are approximately 50% oil. A peanut yield of 2,800 lbs/acre (US average 2000-2005) could produce in excess of 110 gallons of biodiesel, a 50% increase per acre over soybean. Therefore, per unit land area, peanut is the superior choice for a biodiesel feedstock in the SE. However, peanuts are a crop with high oil value and the US actually imports 150 million lb of peanut oil annually. Accordingly, the success of peanut as a feedstock for biodiesel hinges on low input production at the farm level and a marketing system that bypasses traditional food-grade procedures that add excess value to the oil. The production of peanuts as a true oilseed has not been emphasized in the U.S. Thus, a new production system that emphasizes low inputs must be investigated. Of utmost importance in these low input production systems will be pairing cultivars with favorable oil chemistry and tolerance to common diseases with production practices that increase oil or save money. Weed control is the most costly input in such systems. The primary objective of this research project was to investigate low-cost weed control programs for peanuts grown in an oil production system. As opposed to many low-cost weed control studies for traditional peanut production, fixed costs for weed control were pre-selected so that results can feed into economic models being developed. Field studies were conducted at the National Peanut Research Laboratory in Dawson, GA; Clemson University Pee Dee Research & Education Center in Florence, SC; and the Univ. of Florida Plant Science Research and Education Unit in Citra, FL, in 2005 and 2006. Peanut (Arachis hypogaea cv. DP-1) was planted in 4 row plots by 25 or 30 ft. in length. Fields at each location were maintained in a no or low-spray environment for disease and insects. Treatments were a factorial arrangement of weed control cost (4) by application timing (2) in a randomized complete block with 4 replications. Costs were $10, $15, $20, and $25 per acre for herbicides; application timing was either postemergence (POST) only or preemergence (PRE) + POST. The PRE herbicide chosen was pendimethalin; POST herbicides included combinations of paraquat, 2,4-DB, bentazon, imazapic (.5 and 1X rates), or acifluorfen that equaled the assigned cost. Two control treatments not part of the factorial were included for comparison: a nontreated and a high-value treatment (traditional herbicide program). ANOVA results revealed that the two-way interaction between location and treatment were significant. The main effects of year, cost, and application timing, nor their interactions were significant therefore, data are presented by location. Yields at Citra were generally lower than either Dawson or Florence with a range of 90-1710lb/acre. Most common weeds present were sicklepod (Senna obtusifolia), hemp sesbania (Sesbania exaltata), Florida beggarweed (Desmodium tortuosum), and annual morningglory (Ipomoea spp.). Treatments costing > $20/acre were consistently greater in yield versus lower costing herbicide systems, though not always statistically different. No distinction in application timing was made. The lack of annual grass species likely decreased the importance of pendimethalin applied PRE. Treatments 4 and 7 both contained 0.5X rates of imazapic which resulted in less weed control for all species measured. This resulted in significant yield loss for treatments 4 and 7, especially treatment 4 which was no different than the nontreated. Treatment 8 utilized also the 0.5X rate of imazapic, however it was also paired with both pendimethalin PRE and paraquat +