Energy beets: an undiscovered crop for the Southeastern US

Authors: Webster, Theodore; GREY, T - University Of Georgia; Scully, Brian; BRENNEMAN, T - University Of Georgia; Davis, Richard; DUTTA, B - University Of Georgia; Johnson, Wiley - Carroll; Knoll, Joseph - Joe

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/28/2014
Publication Date: 9/28/2014
Citation: Webster, T.M., Grey, T.L., Scully, B.T., Brenneman, T.B., Davis, R.F., Dutta, B., Johnson, W.C., Knoll, J.E. 2014. Energy beets: an undiscovered crop for the Southeastern US [abstract]. Weed Science Society of America Meeting Abstracts. 46:246.

Interpretive Summary:

Technical Abstract: Energy beets (Beta vulgaris), which are sugar beets grown for non-food sources, are a potential winter cash crop for growers in the southeastern U.S. that are planted in the autumn and harvested in the spring, complementing current summer crop rotations. The end-product from energy beets will be industrial sugars that can be processed into ethanol, biodegradable plastics, or some other non-food product. Unlike other potential energy crops, beets have established varieties, agronomic practices, pesticides, and equipment. The challenge will be to adopt those practices developed in other regions of the U.S. to a winter-based system in the southeastern U.S. Two studies were conducted near Chula, GA at the USDA-ARS Jones Research Farm and University of Georgia Lang Research Farm to evaluate the yield potential of energy beets when harvested at different times during the spring and summer. The first study included four non-Roundup Ready beet varieties (EGC-183, EGC-184, EGC-185, and ENC-115) planted 6 October 2011 and 1 November 2012 and the second study had five Roundup Ready varieties (ERR-303, ESR-304, ENR-305, ECR-306, and ERR-313) planted 1 November 2012. Beets were planted in three rows spaced 45 cm apart on a standard bed with 183 cm wheel tracks. The herbicide program included ethofumesate PPI in both studies. In the non-Roundup Ready beets, two POST applications were made at 20 and 40 days after crop emergence and included the tank mixture of desmedipham, phenmedipham, triflusulfuron, clopyralid, and ethofumesate. In the other study, glyphosate and clethedoim were applied at 30 and 60 days after planting, respectively. Maintenance fungicides (azoxystrobin and prothioconazole) were applied as needed. In the non-Roundup Ready beets, there were seven harvest times, initiated approximately 187 days after planting and continuing every three weeks through 318 days after planting. In the Roundup Ready beets, harvest was initiated at 215 days after planting and continued every two weeks for a total of four harvests. Data collection at harvest included: root biomass, foliar biomass, and an estimate of sugar content; roots were liquefied and total solids of the beet juice measured. In the non-Roundup Ready beets, yields were lowest at the first harvest in 2012 (53 to 65 Mg/ha) and 2013 (46 to 64 Mg/ha) and nearly doubled within 6 to 9 weeks, as yields were maximized in mid-June at 250 days after planting in 2012 (103 to 129 Mg/ha) and 230 days after planting in 2013 (90 to 129 Mg/ha). Plant pathogens (Sclerotium root rot and Cercospora leaf spot) were low at early harvests, increasing in intensity as air temperatures and humidity increased. Beet yield declined in July and August (in response to increased disease severity), with final yields ranging from 70 to 110 Mg/ha in 2012 and 28 to 61 Mg/ha in 2013. In the Roundup Ready beets study, yields were 113 Mg/ha during the first week of June and increased to 141 Mg/ha by the third week of July. In both of these studies, winter beets harvested in the spring and early summer had yields that were at least equivalent to average yields in the Midwest U.S., and consistent with the average yields in the Imperial Valley of California 89 Mg/ha, where peak yields approach 142 Mg/ha. Theoretical ethanol yields ranged from 4,760 to 6,730 l/ha (509 to 720 gal/a) at the first harvest and 9,315 to 13,350 l/ha (995 to 1,427 gal/a) in mid-June. In the Roundup Ready beet varieties, the average theoretical ethanol yields over the four harvests ranged from 11,700 to 14,590 l/ha (1,250 to 1,560 gal/a). There is high potential for successful beet production in the coastal plain of the southeastern U.S., providing an agronomic cash crop during the typical winter fallow period with minimal disruption to traditional summer cash crops. Additional studies are underway to evaluate optimum autum