Main content area

Sunflower plant drying and machine harvest efficiency--Southern Plains

Allen, R.R., Wiese, A.F., Hudspeth, E.B. Jr.
Transactions of the ASAE 1979 v.22 no.5 pp. 992
water content, Helianthus annuus, irrigated farming, preharvest treatment, paraquat, desiccation (plant physiology), mechanical harvesting, drying, seeds, combine harvesters, Texas
Research was undertaken to determine the effect of chemical desiccation on plant drying and the efficiency of a modified small grain combine header for harvesting oilseed sunflower. Preharvest plant and seed drying patterns with and without a chemical desiccant (paraquat) were evaluated. After plants reached physiological maturity, seed in untreated plants dried to the safe threshing and moisture storage level of 9 to 10% in about 10 days although heads and stalks remained relatively green at about 70% m.c. The desiccant speeded head and stalk drying by 7 to 10 days but had little effect upon seed drying rate. The heading attachment originally consisted of seed gathering pans (22 X 120 cm) extending ahead of the cutter bar, and a modified large 3-slat 120 cm diam. open reel which was operated at 20 - 25 rev/min, with a travel rate of 4 km/h. In later trials a small 40 cm diam. paddle reel, partially covered with a shield which allowed only heads to enter the auger and prevented excessive lengths of stalk from entering the separator, was substituted for the large reel. A forward rotating shaft with teeth to help keep stalks from being pulled up by the roots and plugging the slats between seed pans was mounted below the cutter bar. The small reel operated at 200 rev/min with a 5 - 6.5 km/h travel rate. The heading attachment permitted harvesting 5 to 7 days earlier at higher m.c. than with an open-reel machine because less stalk was handled and also gave cleaner seed. The potential advantage of earlier drying using chemical desiccants was offset by the cost of chemical application and the ability of the shielded-reel header to harvest sunflower earlier.