Questions and Answers for Using Sunn Hemp (Crotalaria juncea L.) as a Green Manure Cover Crop
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How to Cite

Fall, Thioro, Ariel Freidenreich, Stacy Swartz, Christopher Vincent, Yuncong Li, and Zachary Brym. 2020. “Questions and Answers for Using Sunn Hemp (Crotalaria Juncea L.) As a Green Manure Cover Crop”. EDIS 2020 (5), 4.


This document synthesizes information about the warm season cover crop sunn hemp. The question-and-answer format addresses frequently asked questions for growers with answers that summarize the growing body of sunn hemp research. The information is provided so that growers in Florida can learn about up-to-date cultivation and management options for sunn hemp as well as better understand its practical uses. This document is a follow-up to the following:

Wang, Qingren, Yuncong Li, Waldemar Klassen, and Edward Hanlon. 2015. “Sunn Hemp : A Promising Cover Crop in Florida”. EDIS 2015 (7), 4.

Wang, K., and Robert McSorley. 2004. “Management of Nematodes and Soil Fertility With Sunn Hemp Cover Crop”. EDIS 2004 (18).
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Abdul-Baki, A. A., H. H. Bryan, G. M. Zinati, W. Klassen, M. Codallo, and N. Heckert. 2001. “Biomass Yield and Flower Production in Sunn Hemp: Effect of Cutting the Main Stem.” J. Veg. Crop Prod. 7: 83–104.

Adler, M. J., and C. A. Chase. 2007. “Comparison of the Allelopathic Potential of Leguminous Summer Cover Crops: Cowpea, Sunn Hemp, and Velvet Bean.” HortScience 42(2): 289–293:

Baligar, V. C., and N. K. Fageria. 2007. “Agronomy and Physiology of Tropical Cover Crops.” J. Plant Nutr. 30: 1287–1339:

Chase, C. A., and S. B. Coplin. 2017. “A Cover Crop Mixture for Weed and Sting Nematode Management.” Weed Science Society of America Meeting Abstract 320.

Schomberg, H. H., N. L. Martini, J. C. Diaz-Perez, S. C. Phatak, K. S. Balkcom, and H. L. Bhardwaj. 2007. “Potential for Using Sunn Hemp as a Source of Biomass and Nitrogen for the Piedmont and Coastal Plain Regions of the Southeastern USA.” Agron. J. 99: 1448–1457.

Skinner, E. M., J. C. Díaz-Pérez, S. C. Phatak, H. H. Schomberg, and W. Vencill. 2012. “Allelopathic Effects of Sunnhemp (Crotalaria juncea L.) on Germination of Vegetables and Weeds.” HortScience 47(1): 138–142.

Vincent, C., B. Schaffer, D. L. Rowland, K. W. Migliaccio, J. H. Crane, and Y. Li. 2017. “Sunn Hemp Intercrop and Mulch Increases Papaya Growth and Reduces Wind Speed and Virus Damage.” Scientia Horticulturae 218: 304–315.

Wang, Q., W. Klassen, H. Bryan, Y. C. Li, and A. A. Abdul-Baki. 2003. “Influence of Summer Cover Crops on Growth and Yield of a Subsequent Tomato Crop in South Florida.” Proc. Fla. State Hortic. Soc. 116: 140–143.

Wang, Q. R., Y. C. Li, and W. Klassen. 2007. “Changes of Soil Microbial Biomass Carbon and Nitrogen with Cover Crops and Irrigation in a Tomato Field.” J. Plant Nutr. 30: 623–639:

Wang, Q., Y. C. Li, and W. Klassen. 2005. “Influence of Summer Cover Crops on Conservation of Soil Water and Nutrients in a Subtropical Area.” J. Soil Water Conserv. 60: 58–63.

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