Kenaf Productivity and Morphology. When Grown in Iowa and in Kentucky.

Natural fibers are a promising alternative to synthetic fibers for reinforcing plastic or other composite materials, or fuel purposes. Kenaf (Hibiscus cannabinus L.), a fiber crop is grown to a limited extent in the U.S. predominantly in the Southern states. Producing kenaf in the Midwestern U.S. could provide a local source of these fibers for use in a number of manufactured products and potentially for use as a biofuel feedstock. The objectives of this study were to: 1) compare the productivity and the morphology of kenaf cultivars ‘Tainung 2’ and ‘Whitten’ when grown in Iowa and Kentucky and harvested after the first killing frost; 2) assess kenaf growth over the growing season; and 3) determine management (variety and seed density) effects on kenaf productivity and morphology. When grown in Kentucky in 2014, Tainung 2 yielded 24 Mg ha^-1 whereas Whitten had a yield of 19 Mg ha^-1. In contrast, kenaf grown in Iowa showed a yield of 8 Mg ha^-1. In 2015, kenaf grown in Iowa and Kentucky had similar yield of 12.6 Mg ha-1 on average. When grown in Iowa, kenaf response to variety and seed density was more stable over time than in Kentucky. Therefore, a producer in Kentucky could influence kenaf productivity by changing management practices and variety. Tainung 2 was in general more sensitive to location and to seed density than Whitten. In 2015, Tainung 2 planted at a denser population produced 30% greater biomass than for Whitten and other seed densities. Whitten performed similarly across locations and seed densities. Growing Tainung 2 in Kentucky produced plants with 16% more core fiber than in Iowa, but using that same variety in Iowa would result in higher bast production. Overall, kenaf production is very feasible in Kentucky and Iowa but Kentucky has greater yield potential.