Influence of Row Spacing and Nitrogen Levels on Dry Matter Yields of Kenaf ( Hibiscus cannabinus L.)

Kenaf is a potential annual paper pulp crop. Dry matter yields which are sufficiently high to compete with existing crops in Nebraska are needed. Adaptation and cultural studies were undertaken to determine the levels of productivity that can be expected in Nebraska. Irrigated and nonirrigated studies with different varieties, row spacings, and nitrogen fertilization were studied. Average dry matter yields of kenaf of 3.70 and 6.89 tons per acre were obtained in 5 years of nonirrigated and 2 years of irrigated tests, respectively. In only 2 of the 5 years were kenaf yields sufficiently high under nonirrigation to compete economically with corn or wheat grown under comparable conditions. Average kenaf yields were almost doubled under irrigation but were not considered high enough to compete with corn grown under similar conditions. Kenaf planted at a rate of 15 pounds per acre in rows spaced 14 inches apart gave highest yields in irrigated tests. The data indicate that higher populations (narrower rows or heavier rate within rows) might have yielded more dry matter per acre. Under nonirrigated conditions, yields from 21‐inch rows were highest but were not significantly different from other row spacings tested. Nitrogen applications, up to 150 pounds per acre under irrigation and 100 pounds per acre under nonirrigated conditions, did not significantly increase dry matter yields of kenaf. Kenaf samples harvested from 7‐inch and 28‐inch row spacings (2.0 and 0.8 plants per square foot) received similar compositional ratings for pulping potential.