Castor yield in response to planting date at four locations in the south-central United States

Oilseed crops have potential use in the production of biodiesel. Currently, most oil going into the production of biodiesel is derived from soybean (Gylcine max L.) grown in the central U.S. Inability of the southeastern states to compete with central U.S. soybean production has lead to the search for alternative oilseeds. The high oil content and unique properties of castor (Ricinus communis L.) give it potential for use as biodiesel. However, there is limited information on potential yields, adaptation, and planting dates of adaptation of modern castor cultivars. This study was designed to determine potential yields and ideal planting dates of castor at various locations in Mississippi and Tennessee. A single castor cultivar was sequentially planted at 14 day intervals, at four locations, ranging from Memphis, TN south to Poplarville, MS. Annual planting occurred from 1 April to 1 July at all locations, except the 1 April planting date was excluded from the two northern locations. Mean yield ranged from 89 to 1954 kg ha−1. Northern most locations and earliest plantings resulted in the greatest yields. Precocious flowering of castor immediately after 1 April planting at Shubuta, MS was associated with a lower yield. This flowering event was also observed at Poplarville, but did not significantly affect yield. The yield reductions due to southern planting coupled with precocious flowering at the southern locations seem to indicate a limited zone of adaptation for castor.