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Publications

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

Thioro Fall, Ariel Freidenreich, Stacy Swartz, Christopher Vincent, Yuncong Li, and Zachary Brym

This document synthesizes information about the warm-season cover crop, sunn hemp. It addresses frequently asked questions for growers and summarizes the expanding body of sunn hemp research. The information is provided so growers in Florida can learn about up-to-date cultivation and management options as well as better understand sunn hemp's practical uses. This document is a follow-up to EDIS publications SL 306 (https://edis.ifas.ufl.edu/tr003) and ENY-717 (https://edis.ifas.ufl.edu/ng043).

Sunn Hemp—A Promising Cover Crop in Florida

Qingren Wang, Yuncong Li, Waldemar Klassen, and Edward A. Hanlon Jr.

As one of the promising cover crops under tropical, subtropical, or even template climate, sunn hemp (Crotalaria Juncea L.) has shown great advantages in improving soil fertility and increasing the yield and quality for subsequent cash crops. Due to the leguminous feature, sunn hemp can grow well in the soil with poor fertility, grow fast, accumulate a significant amount of nitrogen from soil, suppress weeds and soil root-knot nematodes, and tolerate dry and wet environmental conditions. Therefore, this article aims to elucidate unique features, origin, plant growth, handling, potential benefits, and the limitation in seed production of sunn hemp. It provides basic information to growers, stakeholders, and anyone interested in growing cover crops for crop rotation to optimize the cropping systems for sustainable agriculture.

Management of Nematodes and Soil Fertility with Sunn Hemp Cover Crop

K. -H. Wang, R. McSorley, and Z.J. Grabau

Sunn hemp, Crotalaria juncea L. is a rapidly growing crop used for fiber production in India and Pakistan. It is popular as a green manure in many tropical and subtropical areas in the world, and is also valued because it suppresses weeds, slows soil erosion, and reduces root-knot nematode populations. Recently, as cultivars adapted for seed production in the southeastern United States have been introduced, there is a growing interest in rotating sunn hemp with agronomic crops in the southern United States and in using sunn hemp as a summer cover crop in Florida and other southeastern states. This publication informs agricultural professionals about the impacts of sunn hemp cover cropping on soil fertility and plant-parasitic nematodes.