Promoting Tropical Cover Crop Mulch Systems for Minimum-Till Crop Production in the U.S. Virgin Islands

Project Overview

Project Type: On-Farm Research
Funds awarded in 2011: $14,957.00
Projected End Date: 12/31/2014
Region: Southern
State: U.S. Virgin Islands
Principal Investigator:
Dr. Stuart Weiss
Tarleton State University

Annual Reports


  • Fruits: melons
  • Vegetables: beets, cabbages, cucurbits, eggplant, peppers, tomatoes
  • Additional Plants: herbs


  • Crop Production: conservation tillage
  • Education and Training: demonstration, extension, on-farm/ranch research, participatory research
  • Farm Business Management: whole farm planning, cooperatives
  • Natural Resources/Environment: carbon sequestration, biodiversity, soil stabilization
  • Pest Management: cultural control, mulches - killed, mulches - living, mulching - vegetative
  • Production Systems: agroecosystems, holistic management, organic agriculture
  • Soil Management: green manures, organic matter, soil analysis, nutrient mineralization, soil quality/health
  • Sustainable Communities: ethnic differences/cultural and demographic change, local and regional food systems, sustainability measures

    Proposal abstract:

    Sustainable agriculture is a critical component to the social, economic, environmental, and political stability of the U.S. Virgin Islands (USVI). Virgin Island's farmers face unique challenges to sustainable agriculture as a result of geographic, environmental, and socio-economic conditions that exist in the USVI. Low-external-input farming is a reality for local agricultural systems in the USVI because conventional agricultural inputs are costly or difficult to acquire. The tropical environment poses extreme challenges for the management of soil fertility, agricultural pests, and water resources where farmers have limited options to address these management concerns. Soil fertility and pest management create unique challenges to USVI farmers in that imported fertilizers and pesticides are 2-to 3-times the cost of inputs in the continental USA and they require costly specialized application equipment to which USVI's farmers have little or no access. Thus, inorganic commercial fertilizers, bulk soil amendments, and chemical pesticides are not economically feasible for many smallholder farmers. Cover crop and green manure systems are one of the most promising technologies which farmers could adopt to support sustainable soil fertility levels, and agricultural improvements (Snapp et al., 1998); however, in order to be put into practice, a protocol for green manure/cover crop residue as mulch in minimum-till low-external-input farming systems is needed for our region. Minimum- till, mechanical-kill systems for cover crops have proven to be cost efficient, all while improving soil organic matter and providing weed suppression (Curran et al., 2010). Our project includes fabrication of a research and demonstration roller-crimper (a.k.a knife roller) implement for use by the Agriculture Experiment Station and the Cooperative Extension Service, which local farmers can test, copy, and fabricate, for their own on-farm use. The roller-crimper implement will mechanically kill tropical cover crops by severing or crushing the plants vascular system resulting in surface residue that provides soil cover, which results in an organic mulch that will reduce soil erosion, lower soil surface temperatures, minimize soil nutrient loss, reduce weed germination and growth, and decrease soil water loss. Leguminous cover crop species can fix nitrogen in the soil, which is especially important in the tropics, as degradation of soil nutrients occur rapidly under tropical environmental conditions (Smithson and Giller, 2002). Therefore, 5 leguminous (Crotalaria juncea, Dolichos lab lab, Clitoria ternetea, Cajanus cajan, and Vigna unguculatta) and 2 graminaceous (Pennisetum glaucum and Sorghum bicolor x S. sudanense ) cover crops will be evaluated. This research will test the response of mechanically killed tropical cover crops by a roller-crimper for their continued use as organic mulch in minimum-till vegetable crop production systems. Research will determine biomass production of 6 different tropical cover crop species, cover crop plant tissue nutrient levels, and post termination cover crop re-growth and weed suppression capability. Expected benefits of this cultural practice include the creation of nutrient-rich mulch that will last until the harvest of the following crop and thereby, shade the soil and reduce water loss from evaporation, protect the soil against erosion, reduce weed germination and development, and serve as an organic soil amendment to increase soil fertility. Curran W., M. Ryan, and S. Mirsky. 2010. Cover crop rollers for Northeastern grain production. Penn State University USDA-ARS. Available at: Smithson, P.C., and K.E. Giller. 2002. Appropriate farm management practices for alleviating N and P deficiencies in low-nutrient soils of the tropics. Plant and Soil. 245.1: 169-180. Snapp, S.S., P.L. Mafongoya, and S. Waddington. 1998. Organic matter technologies for integrated nutrient management in smallholder cropping systems of Southern Africa. Agric. Ecosyst. Environ. 71: 185-200.

    Project objectives from proposal:

    Project Objectives:

    1.) To construct a roller-crimper from locally available recycled materials for use in on-farm research and to demonstrate the effectiveness of the roller crimper to kill tropical cover crops to produce surface sheet mulch.

    2.) To evaluate the biomass production of 6 different tropical cover crop species.

    3.) To evaluate the effectiveness of the roller-crimper to successfully kill 6 different cover crop species and provide suitable surface sheet mulch for soil quality enhancement and weed suppression in subsequent vegetable crop production systems.

    4.) To determine cover crop re-growth and weed suppression capability in cover crop surface sheet mulch (6 species) post termination with a roller-crimper.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.