Adoption of Improved Crop and Soil Management Practices to Eliminate Bare-Ground Fallow and Reduce Reliance on Pesticides by Hawaii Farmers
Many farmers in Hawaii do not follow consistent IPM or effective sustainable farming practices. This is in large part due to lack of demonstration that the practices can work effectively and to lack of specific motivation to change. This project includes an educational component for students interested in agriculture as well as for the established working farmers. It will include a demonstration project with involvement of students, surveys of growers' current practices, outreach to growers, and on farm participation with growers to facilitate adoption of IPM practices.
A serious concern addressed by this project is the lack of sustainable soil management. Many Hawaiian growers practice bare-ground fallow between cropping cycles as a way of reducing weed pressure and soil borne pest problems. However, this has resulted in excessive soil run-off into fragile marine environments, development of soil subsurface hardpan, and reliance on herbicides for weed control. The soil hardpan further restricts plant root system growth and permeability to irrigation water exacerbating the run-off problem. Alternative proposed practices include soil amendments such as molasses, pineapple processing waste, bagasse and several bioactive products that are available at little or no cost in Hawaii. Cover crops have also proven effective for soil and pest management. The selection of new, alternative practices will be made on an individual basis for each farmer based on their current practice. Finally, the information demonstrated and practiced in the project as well as the outcomes and changes in farming practices will be disseminated to all Hawaii growers.
Project goals and objectives
1. Reduce and/or eliminate bare-ground fallow.
2. Engage the community in the project (Waiahua High School, Pioneer Hi-Bred International, inc., growers, agricultural product suppliers).
3. Test a variety of sustainable cropping methods and soil additives for yield improvement with the long term objective of grower adoption.
On farm cover crop plantings of oats, winter wheat, sunn hemp, and lana vetch were established during the 2003/2004 rainy season (mid-October to mid-April) to: 1) demonstrate benefits of cover crops to growers, and 2) provide control of soil borne pests such as nematodes and suppression of weeds with the ultimate goal of grower adoption. Weed control, especially, has been a major reason for the bare ground fallow practice. Sites selected for demonstration cover crop plantings had high weed and nematode pressure. Additionally, two compost teas used by organic farmers, Enhanced Microorganisms (EM) and Liquid Compost Factor (LCF), were examined for impact on soil nematode populations.
The project enlisted the cooperation of several North Shore grower participants for the on-farm plantings. Junior and senior students from Waialua High School assisted with plot establishment and research data collection, analysis, and presentation. Pioneer Hi-Bred International, Inc. was instrumental in providing student help for the project.
As a direct result of the effort expended during the 2003/2004 rainy season more than 1,550 acres of farmland were planted to a variety of cover crops during the 2004/2005 rainy season on Oahu. The most commonly grown cover crops were oats, winter wheat, and sunn hemp. The stated goal for grower adoption of Best Management Practices (BMP) for the 2003 to 2005 project effort was 500 acres by project completion. Reniform nematodes were reduced by 95% in a large oat cover crop planting on farm land previously cropped to pineapple. EM and LCF trials were not effective in reducing nematode levels. All cover crop plantings gave excellent weed suppression when planted at recommended rates. Sunn hemp and oats gave the best overall weed suppression.
Follow up efforts include the purchase of a grain harvester with a grant from USDA-NRCS Oahu Resource Conservation and Development program in order to produce sunn hemp seed for Hawaii and a grant proposal submitted to the Western Sustainable Agriculture Research and Education program to demonstrate the utility, and further facilitate the adoption, of various cover crops as green manures.