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Feature: Our 'Tropic Sun' Shines

NRCS Plant Materials Centers partner to develop innovative plant technologies for conservation solutions.

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'Tropic Sun' sunn hemp field at the Hoolehua Plant Materials Center
David Duvauchelle, Resource Specialist, Hoolehua PMC

Foundation seed of 'Tropic Sun' sunn hemp was planted at the Hoolehua Plant Materials Center 2007. 'Tropic Sun' sunn hemp, Crotalaria juncea, a fast growing leguminous green manure cover crop, is ideal for improving soil fertility, controlling erosion, suppressing weeds, and reducing rootknot nematode populations. When incorporated into a crop rotation system, 'Tropic Sun' sunn hemp can provide up to 150 pounds of actual nitrogen per acre and produce up to 3 tons of organic matter per acre in 60 days.


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 Foundation seed of 'Tropic Sun' sunn hemp planted at the Hoolehua Plant Materials Center 2007.
Glenn Sakamoto, PMC Manager, Hoolehua PMC
 

Recently, the Hoolehua Plant Materials Center (PMC) release ‘Tropic Sun’ Sunn Hemp has gained some national attention. With the rising costs of fuel, the cost to) produce commercial fertilizers has also risen. The once high cost to fertilize fields by planting a green-manure crop such as ‘Tropic Sun’ is now beginning to look like the more economical choice for farmers. Add the fact that it reduces nematodes in addition to incorporating organic matter into the soil; this option is looking better and better everyday.

Currently, Plant Materials Centers throughout the Nation are all working simultaneously on this study to determine the geographical limitations of ‘Tropic Sun’. The study will look at biomass yields at 30 days after planting (DAP), 60 DAP, and 90 DAP to identify where ‘Tropic Sun’ may and may not grow reasonably well.

Crotalaria juncea (sunn hemp): Sunn hemp grows well throughout the Pacific Islands Area. The cultivar ‘Tropic Sun’ is an excellent cover/green manure crop and is resistant to root-knot and reniform nematodes. It is becoming popular in California and the South. The restrictions on the use of methyl bromide have increased its popularity because of its ability to control nematodes. Growers in southern Florida are, apparently, only moderately successful in producing ‘Tropic Sun’ seed on a commercial scale. The seed is commercially produced on Oahu and approximately 12,000 pounds were produced in 2008.

If you encounter any problems with the files provided on this page, please contact Leslie Glass at 701-250-4330.

The following document requires Acrobat Reader

'Tropic Sun' Sunn Hemp Release Brochure. (PDF; 229 KB) Glenn Sakamoto, Robert Joy and Jolene Lau. 2009. Hoolehua Plant Materials Center, March 2009. 2p. (ID# 8433)

Plant Materials Centers taking part in the study

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