Agriculture and Polluted Runoff
Agriculture: With Opportunities Come Responsibility
Coffee arrived in Hawai`i in the early 1800s and by the early 1900s it was grown on all of the major Hawai`ian islands. Hawai`i has roughly 6,500 acres of coffee statewide. Hawai`i Coffee Association
Hawai`i, with its year-round growing season and isolation, supports a variety of agricultural products. Long known for sugarcane and pineapple, Hawai`i’s farm economy is in transition to a much more diversified product mix with many smaller operations. Hawai`i now leads the nation in sales of several tropical commodities.
With the great opportunities that Hawai`i has to offer its farmers, it also brings a responsibility to protect Hawai`i’s water resources. EPA’s Agriculture Strategic Plan for the Pacific Southwest Region notes that agriculture is the nation’s leading source of pollution for ground, surface and coastal waters. Livestock and crop farming practices can contribute pollutants such as sediments, nutrients from fertilizers and animal waste, pesticides, herbicides, and bacteria from animal waste to local waterways. By choosing sustainable farming practices, farmers can reduce the amount of polluted runoff from their farms. Several examples of sustainable farming practices are described below.
Develop a Conservation Plan
Working with local Soil and Water Conservation Districts (SWCDs), farmers and ranchers can develop a unique plan for their property that will improve water efficiency, decrease erosion and minimize their environmental impact. A conservation plan addresses pollutants in farm runoff with nutrient and pest management strategies. Conservation cover and mulching recommendations address the quantity of farm runoff. Conservation plans also provide information about soils and nearby streams, aquifers, ditches and other water resources. To find the SWCD in your area, visit the Hawai`i Association of Conservation Districts Web site.
Conserve and Protect Water Resources
It is important for farmers to adopt practices that will keep rain and irrigation water on their property to prevent polluted runoff from entering nearby streams and rivers. These practices will protect local waterbodies and also prove helpful during times of drought and water shortages. Farmers can conserve water resources by using water more efficiently, improving on-farm retention of water, reducing water demand, and increasing soil content and soil moisture. EPA’s Sustainable Water Infrastructure Web site provides links and suggests ways that farmers can conserve water.
For livestock farmers, it is important to have access to an adequate supply of water that is clean enough to support healthy animals. Livestock farmers need to be careful that animal wastes do not contaminate drinking water sources for livestock and wildlife. Guidance on how to implement proper techniques for managing animal waste can be found at:
- Concentrated Animal Feeding Operations (CAFOs) Fact Sheets
- Natural Resources Conservation Service Animal Waste Management
Properly Apply and Time the Application of Fertilizers, Pesticides and Herbicides
Taro was brought to Hawai`i by Polynesian settlers about 1500 years ago. Taro can be grown as wetland in a series of ponds (pictured above) called lo’i or in dry, upland areas where watering is supplied by rainfall or supplemental irrigation. The bulk of taro is made into poi. Other processed uses for taro include a traditional Hawai`ian dessert called Kulolo (a mixture of taro and coconut cream and/or shredded coconut meat) and chips. USDA
Fertilizers, herbicides and pesticides are often applied to improve production, but when applied improperly, these nutrients and chemicals often enter our waterways. Before fertilizers are applied, a soil test should be administered to determine exactly which, if any, fertilizers should be applied. Hawai`i’s Cooperative Extension Service provides information on how to conduct a soil test in its paper “Testing Your Soil: Why and How to Take a Soil-Test Sample “. Fertilizers should be used sparingly and applied when rain is not in the immediate forecast. Organic fertilizers are also known to release nutrients more slowly, allowing a longer treatment of the soil.
Pesticides are chemicals that are intended to kill or repel a pest such as unwanted insects, weeds, rats, germs and fungus. It is important to properly use and dispose of pesticides in order to keep these harmful chemicals out of Hawai`i’s waterways. All pesticides should be carefully applied per the label’s instructions. Old and unused pesticides require special disposal and should not be thrown out in the trash or poured down the drain. To learn where pesticides can be properly disposed of, visit the Hawai`i Department of Agriculture site. The Hawai’i Department of Agriculture’s Plant Pest Control Branch also provides updates of the latest pests that are affecting Hawai`i on their Pest Advisory Web page.
Protect Soil Resources: Plant Cover Crops
Exposed soil can be easily washed away by rain and irrigation water into nearby waterbodies. Sediment clouds the waters and aquatic animals (including corals) can be smothered. It is important to keep soil on the land and out of waterways. After harvesting, cover crops should be planted. Range and grazing lands should also be planted year-round.
- The College of Tropical Agriculture and Human Resources offers a listing of recommended cover crops and “green” manures.
- CTAHR provides a slideshow on groundcover use and establishment in sustainable papaya orchards.
Past Agricultural 319 Projects
319 Grants have been used to address polluted runoff from agriculture. Examples of past projects are listed below.
- The Integration of Aquaculture with Taro Production in Hawai`i: A Commercial Demonstration of Pollution Abatement, Soil and Water Conservation, Controlled Eutrophication and Waste Recovery
- Demonstration and Training in Critical Area Stabilization Techniques on Agricultural Roads and Unprotected Waterways East and West Kauai
Pili grass (above) is mostly grown on the island of Moloka’i, Maui and the big island. For some restoration projects, pili grass is bundled into bales and used for erosion control (below). The bales are made by picking the seeds of the mature grass and rolling them into a hay bale. The seeds are still viable. When the seeds come in contact with water, they “dig” into the ground and become established.
Pili grass bundles.
- Polluted Runoff Control for Waialee Livestock Farm
- Early Warning Indicators of Ground Water Contamination in Soils with Variable Charge Clays
- Cover Crops for Erosion Control in Ko’olaupoko
- Contaminant Control by Cover and Residue Management on Agricultural Land in the Pearl Harbor Basin
- Cover Cropping for Reducing Soil Nitrogen Following Seed Corn Production in the Kaiaka-Waialua Watershed
- Erosion Control Studies for Agricultural Roads in the Kaiaka – Waialua HUA:
- Reducing Nonpoint Source Pollution from Sediments and Herbicides in Orchards in the Kaiaka-Waialua HUA
- Reducing Nonpoint Source Pollution from Sugarcane Fields by Cereal Cover Cropping in Kaiaka – Waialua HUA
- Best Management Practices to Reduce Runoff from Pineapple Fields, West Maui
- West Maui SWCD Best Management Plan Improvement on Maui Pineapple Co. and Pioneer Mill Co. Land
- West Maui SWCD – Pioneer Mill Company Sediment and Erosion Control
Hawai`i Watersheds (The Big Island)
- Animal Waste Management Program in Hawai`i: Implementation and Evaluation of the Modified Deep Litter System Under a Tropical Agricultural Ecosystem
- Fact Sheet: Protecting Water Quality from Agricultural Runoff
- Hawai`i Department of Agriculture: Pesticides
- EPA Region 9: Water and Energy Efficiency for Agriculture
- NRCS Pacific Islands Area Technical Resources
- A Landowner’s Manual: Managing Agriculture Irrigation Drainage Water
- National Management Measures to Control Nonpoint Source Pollution from Agriculture
- Polluted Runoff Agricultural Links
- Agriculture in the Pacific Southwest Region – Region 9 Agriculture Strategic Plan FY2003 through FY2008
- Hawai`i Association of Conservation Districts (HACD)
- University of Hawai`i, College of Tropical Agriculture and Human Resources (CTAHR)
- Hawai`i Water Quality Extension Program
- Natural Resources Conservation Service (NRCS) Pacific Islands
- Hawai`i Livestock Waste Management Guidelines