Cover crops, an old agricultural conservation practice, are part of the new vision of young farmers in the Caribbean Area who are planting diverse species to maintain soil health. Cover crops can benefit the environment by:
Improving the natural biological processes in the soil,
Reducing soil erosion,
Increasing organic matter,
Maintaining and improving water quantity and quality, and
Reducing soil compaction
Cover crops have been used in the Caribbean Area since the early 1900’s, but recently their on-farm application has gained in popularity and importance.
Crotalaria juncea - Sunn hemp
José V. Fabre has been growing cover crops on his banana, citrus and vegetable farm for the past two years. On his 30 acres of bananas, José grows Canavalia ensiformis—an herbaceous, erect to viny legume (also called sword bean). Its vigorous growth inhibits most weed development, and in favorable conditions it can produce up to 80,000 pounds of green material and 231 pounds of nitrogen per acre. Since he began using cover crops on his farm, José has reduced his use of glyphosate fertilizer by 83%. He has also reduced sediment deposition to his drainage canals so much that he only needs to maintain them twice a year, compared to his previous quarterly maintenance schedule. His irrigation cycles have also dropped by 50%, dramatically reducing his energy use. All this while maintaining the same banana yields as when he used conventional farming practices. He also uses Geophila macropoda, a well-known soil-improver, in his banana fields, and is planning to establish Crotalaria juncea (Sunn hemp) in his pineapple fields.
Jose V. Fabre showing Canavalia ensiformis on his banana plantation in Sabana Grande, Puerto Rico.
Canavalia ensiformis, sword bean.
Crotalaria juncea, or Sunn hemp, is an annual erect legume with fibrous stems up to 6-8 feet high. It can fix nitrogen from the atmosphere into the soil, and produces abundant organic matter. In Puerto Rico, yields after 120 days average 1,651 pounds per acre biomass and 54 pounds per acre of nitrogen. Crotalaria juncea produces an allelopathic substance that is toxic to many nematodes, reducing their populations in the soil. The plants are ready to incorporate into the soil when flowering, about 60 days after planting. Sunn hemp also attracts pollinators, mainly bumblebees.
Sunn hemp flowers
Duamed Colón has a small plantain farm in Gurabo, Puerto Rico, where he has been planting cover crops for two years. Duamed also produces Canavalia seed as part of his agricultural enterprise. He began by planting just Canavalia, but now he is mixing Canavalia with Crotalaria. Some of Dumed’s results are:
Reduced fungicide use for Black Sigatoka by 78%;
Reduced nematicide use by 50%; and
Reduced herbicide use by 72%.
Duamed Colon on his plantain plantation with Sunn hemp (Crotalaria juncea).
Plantains with a Canavalia ensiformis cover crop.
For more information
For more information on cover crops in the Caribbean Area, contact Plant Materials Specialist, Edwin Más, at 787-831-3416 x.106.