UVI Research and Technology Park

Sustainable Tropical Leguminous Cover Crop and Green Manure Mulch Systems

Developing Sustainable Tropical Leguminous Cover Crop and Green Manure Mulch Systems for Low-External-Input crop Production in the U.S. Virgin Islands, Puerto Rico, and Florida

Stuart A. Weiss sweiss@live.uvi.edu

Elide Valencia elideval@uprm.edu

Danielle D. Treadwell ddtreadw@ufl.edu


Tropical smallholder farmers operating under low-external-input (LEI) conditions rely upon non-intensive on-farm or locally available inputs for agricultural production; however, such resources are limited in the tropics. Weeds are recognized as one of the top threats to sustainable crop production by farmers. Leguminous cover crops and green manures (CC/GM) used as surface mulch in minimum-till agroecosystems may improve soil quality and provide alternative weed management strategies.


  • To assess two mucuna (Mucuna pruriens L. cv. Vine 90 and Dwarf) varieties and cowpea (Vigna unguiculata cv. Iron Clay) as a cover crop and then as a green manure (CC/GM) where the crop residue is terminated with a roller-crimper to produce organic sheet mulch. 
  • To evaluate and compare five tropical CC/GM species to each other and to a weedy fallow in rotation with a subsequent minimum-till hot pepper (Capsicum chinense Jacq.) rotation where the CC/GM residue is mechanically (roller-crimper) killed for surface sheet mulch for weed suppression and to improve soil quality.
  • To evaluate sunn hemp as a CC/GM rotation with hot pepper production where the crop residue is either mechanically (roller-crimper) killed for surface sheet mulch or is green chopped and soil incorporated to determine effects on soil quality and weed suppression in comparison to 3 common cultural weed management practices. 


  • Determine the effectiveness of mechanical termination with a roller crimper on tropical pulse cover crop species such as cowpea, velvet bean, and pigeon pea.
  • Identify and test additional crop species that can be successfully terminated with a roller crimper to produce surface sheet mulch. 
  • Design year round cover crop management strategies using a roller crimper for mechanical cover crop termination.
  • Determine if cover crop residue resulting from mechanical termination with a roller crimper can provide adequate weed suppression compared to conventional weed control methods for subsequent vegetable crop production..

Anticipated Outcomes and Benefits

This project hopes to develop alternative weed suppression strategies for tropical vegetable production that utilize cover crop residue as surface sheet mulch.  The benefits of this system are the reduction or elimination of herbicides and mechanical weeding.  Cover crop surface sheet mulch systems for vegetable production will be compared to other weed suppression practices such as plastic mulch and hay mulch.     


  • Southern-Sustainable Agriculture Research and Education (SARE) Research and Education Grant

University of the Virgin Islands
Agricultural Experiment Station
RR 1 Box 10,000
Kingshill, VI 00850
Telephone: (340) 692-4020 Fax: (340) 692-4035