Submitted to: Subtropical Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 24, 1997
Publication Date: N/A
Interpretive Summary: The long term drought in south Texas is resulting in reduced water allocation to farmers. Cassava is a durable, drought-tolerant plant which can be utilized for feedstock, processed, fresh consumption or fermented and distilled for use in oxygenated fuels. Information on cassava adaptability to the LRGV is lacking. A preliminary study in 1996 suggests that modest yields of 5 to 9 Mt / ha 230 days after propagating can be achieved with nominal water (36 cm) and fertilizer (50 kg N/ha) inputs. Accessions tested varied in their tolerance to a calcareous, high pH soil, and a major freezing event, but yields were statistically comparable. Plant stems and roots growing below the soil line remained viable after a temperature of -5.7C on 19 December 1996.
Four cassava (Manihot esculenta, Crantz) accessions were received from the USDA, ARS Plant Introduction Station in Mayaguez, PR, on 16 January 1996. The next day, the 15 to 20 cm long cuttings were propagated individually in 1 gal. pots containing Metro Mix No. 4 for ten weeks before field setting in a transition Hidalgo-McAllen sandy loam soil at the Moore Air Base site near McCook, TX. Three plant establishment methods, control (no soil ammendment), addition of 15 Mt bagasse/ha, or 50 kg cross-linked polyacrylamide/ha into the planting trench were evaluated. The 2 x 1.2 m spacings on 15 cm high beds provided 4036 plants/ha. Plants received a total of 35.8 cm of water between field planting and harvest (230 days). Mid- and late season soil moisture at 38 cm depth only was lowest in soil containing bagasse. Establishment method had little or no effect on plant size, leaf nutrients, leaf pigment concentrations, root dry matter or root yield. Accessions differed in many of these attributes except root yield, the means of which ranged from 5 to 9 Mt/ha. Aerial parts of accessions were killed by a temperature of -5.4 C on 19 December with accession mean survival rates of 40 to 72% on 23 March 1997.