Skip to main content
ARS Home » Research » Publications at this Location » Publication #256414
Title: Monoculture and polyculture: Kenaf (Hibiscus cannabinus) and sunn hemp (Crotalaria juncea)

Author
item Webber Iii, Charles
item DICKSTEIN, REBECCA - University Of North Texas
item AYRE, BRIAN - University Of North Texas
item D'SOUZA, NANDIKA - University Of North Texas
item STEVENS, KEVIN - University Of North Texas
item CHAPMAN, KENT - University Of North Texas
item ALLEN, MICHAEL - University Of North Texas
item DAGNON, KOFFI - University Of North Texas

Submitted to: Journal of Environmental Monitoring and Restoration
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2011
Publication Date: 2/27/2012
Citation: Webber III, C.L., Dickstein, R., Ayre, B.G., D'Souza, N.A., Stevens, K.J., Chapman, K., Allen, M.S., Dagnon, K.M. 2012. Monoculture and polyculture: Kenaf (Hibiscus cannabinus) and sunn hemp (Crotalaria juncea). Journal of Environmental Monitoring and Restoration. 7:26-33.

Interpretive Summary: Kenaf (Hibiscus cannabinus L.) and sunn hemp (Crotalaria juncea L.) are fast growing summer annual crops with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). Field research was conducted in southeast Oklahoma (Lane, OK) to compare monoculture and polyculture production of these two crops. The experiment was arranged in a randomized complete block design (RCBD) with 3 planting regimes, 4 harvest dates, and 4 replications. Kenaf ‘Tainung #2’ and sunn hemp ‘Tropic Sun’ were planted on June 1, 2009 on a Bernow fine sandy loam, 0-3% slope (fine-loamy, siliceous, thermic Glossic Paleudalf) soil in 4 rows with a 76 cm spacing between rows in plots 3 m wide and 9.1 m long. Kenaf and sunn hemp were each planted as monocultures with final population stands of 430,547 plants/ha, and as a polyculture with a combined plant stand of 430,547 plants/ha. Kenaf and sunn hemp plants were harvested plants at 45-, 90-, 135-, and 177-days after planting (DAP). Plant height, stalk diameter, leaf and stalk yields were determined for each harvest. Independent of production system (monoculture or polyculture), kenaf produced greater stalk heights, basal stalk diameters, stalk percentages, and stalk yields at the final harvest (177 DAP) than did sunn hemp. The differences between crops increased with plant maturity (harvest date). Sunn hemp plant heights, basal stalk diameters, leaf, and stalk yields peaked by 135 DAP. Kenaf and sunn hemp leaf percentages and yields peaked at 90 DAP, independent of cropping system. There does not appear to be any short term advantage of growing these two crops in polyculture. Different varieties may influence the relative response to the cropping systems. It is also possible that long term benefits to soil quality, and to insect or disease control might be evident in a polyculture system. Additional research should investigate additional varieties and the potential long term benefit on soil fertility as a result of the nitrogen fixation ability of sunn hemp.

Technical Abstract: Kenaf (Hibiscus cannabinus L.) and sunn hemp (Crotalaria juncea L.) are fast growing summer annual crops with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). Field research was conducted in southeast Oklahoma (Lane, OK) to compare monoculture and polyculture production of these two crops. The experiment was arranged in a randomized complete block design (RCBD) with 3 planting regimes, 4 harvest dates, and 4 replications. Kenaf ‘Tainung #2’ and sunn hemp ‘Tropic Sun’ were planted on June 1, 2009 on a Bernow fine sandy loam, 0-3% slope (fine-loamy, siliceous, thermic Glossic Paleudalf) soil in 4 rows with a 76 cm spacing between rows in plots 3 m wide and 9.1 m long. Kenaf and sunn hemp were each planted as monocultures with final population stands of 430,547 plants/ha, and as a polyculture with a combined plant stand of 430,547 plants/ha. Kenaf and sunn hemp plants were harvested plants at 45-, 90-, 135-, and 177-days after planting (DAP). Plant height, stalk diameter, leaf and stalk yields were determined for each harvest. Kenaf leaf and stalk yields were greater than sunn hemp when comparing within the polycultures and between the monocultures. Stalk yields and stalk biomass percentages for both crops increased with each harvest date across cropping systems. Leaf biomass percentages decreased with each harvest date and leaf yields peaked at 135 DAP. The monoculture of each crop produced as good or better crop yields and individual stalk parameters (plant weight, plant height and stalk diameter) than crops grown in polyculture. These initial results provide no short term incentive for producing kenaf and sunn hemp in polyculture.