Soil Health Resource Guide - Oahu Resource Conservation and Development Council

Hawaiʻi Soil Health Resource Guide

This resource guide contains useful information for farmers and ranchers interested in building better soil on agricultural lands. A soil in good health can improve irrigation efficiency, reduce fertilization needs, reduce pest pressure, reduce erosion, and improve overall plant productivity. Hawai‘i’s unique island landscapes and history of soil degradation through intensive crop production heighten the importance and benefit of rebuilding soil health.

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The resources we’ve pulled together are broken down into eight categories, each with a brief description. Individual experts or entities are listed to help you know who to reach out to with questions or to learn more. We welcome you to stay in touch with our organization’s work to support Hawaii’s soil health movement via our website and newsletter.

Service providers that wish to be included in our resource packet can send us an info sheet and/or website link to admin@oahurcd.org.

Soil Health Management Plans

Soil health management planning is a new tool in Hawaii, used to identify and document soil health resource concerns and develop goals to improve overall soil health. Planning creates a comprehensive overview tool for the farmer to see where there may be missed opportunities to build soil health and what management goals to prioritize. Plans can also help communicate goals with other local producers, and demonstrate interest in resources available for soil health. Below are the organizations we know of offering soil health planning services.

Oahu Resource Conservation and Development Council – Oahu RC&D is piloting soil health management planning to address the growing interest among Hawaii producers to build soil health.
USDA Natural Resource Conservation Service (NRCS) – NRCS offers technical and financial assistance to help producers plan and implement soil health management plans. The Environmental Quality Incentive Program (EQIP) program provides funding support through contracts with eligible producers to obtain services of certified TSPs for development of Soil Health Management Plans. Certified TSP’s can be found here – NRCS Technical Service Provider Locator

Soil Testing Services

Soil health and soil nutrient testing assist land stewards in making informed management decisions. Soil nutrient testing can optimize crop production and protection of natural resources. Soil can be assessed for its health in biological, chemical, and physical properties. These soil properties support diverse processes critical to productive, resilient, and sustainable farms. We do not endorse any specific service providers or products.

Crop Nutrient Solutions – Soil analysis and crop nutrient recommendations on how to amend the soil from agronomist Pete Bunn.
Hawaiʻi Soil Health Program – Testing services provide an estimate of your farm’s soil health status using a soil health index developed specifically for the soils of Hawaiʻi by University of Hawaii faculty Dr. Susan Crow and Dr. Jonathan Deenik.
Agricultural Diagnostic Service Center (ADSC) – Conducts chemical analyses of soils as well as other diagnostic tests. ADSC is a laboratory that provides analytical results. Specific recommendations for corrective actions based on these analytical results are prescribed by CTAHR extension agents or other specialists.

Online Tools for Farmers

These free online resources provide site specific information for land stewards to use in supporting management decisions.

Cover Crop Calculator – Cover cropping benefits the soil, environment, and farm. Nitrogen-fixing species result in net gains of nitrogen in your agroecosystem. This calculator uses plant-available nitrogen mineralization rates from different areas, nitrogen content, and biomass production of cover crop residues to estimate the nitrogen contribution from cover crop residues in Hawaii.
Hawaii Soil Atlas – Input the location of your farm and this website will provide general information on soil attributes such as water retention, fertility, acidity or alkalinity, organic matter, and physical structure based on the mapped soil series.
Web Soil Survey – A soil report can be generated for a farm, ranch, or other planning area to provide soil data and information produced by the National Cooperative Soil Survey.

In-Field Tools for Farmers

NRCS Soil Health Assessment – Provides information on the indicators of soil health and assessments that can be done in crop fields to assess the physical, chemical, and biological properties of soils. This assessment is designed as a diagnostic tool to determine and document if soil health resource concerns exist.
NRCS Pasture Health Assessment – The Guide to Pasture Condition Scoring provides a systematic way to check how well a pasture is managed and assess for resource concerns related to biotic integrity, soil/site stability, and hydrologic function.

Practices to Support Soil Health

Principals that support soil functioning include maintaining the presence of living roots, limiting disturbance, maximizing soil cover, and maximizing biodiversity. A small selection of practices that can help achieve these principles are listed below. Financial support from NRCS assistance programs or other funding sources may be available for implementing soil health practices.

Cover Cropping – Integrating cover crops to your farm cycle can increase the biodiversity, soil cover, and living roots in your soil. This practice can address pest concerns, suppress weeds, break up compacted soils, fix-nitrogen, scavenge nutrients, and build soil carbon.
Cover Crop Chart for Hawaii
Cover Crops and Green Manures
Conservation Practice Standard Cover Crop (Code 340)
Mulch – Mulching conserves soil moisture, is a source of organic matter, lowers soil temperature, and protects your soil against raindrop impact.
Mulching for Healthier Landscape Plants
Conservation Practice Standard Mulching (Code 484)
NoTill/Reduce Till – Tilling breaks up soil structure, soil biological communities, and can create a compaction layer over time which adversely affects agro-ecosystems.
Conservation Practice Standard Reduced Till(Code 345)
Conservation Practice Standard No Till (Code 329)
Nutrient Management – Managing the rate, source, placement, and timing of soil amendments and nutrient applications can benefit the soil and environment. Building soil organic matter through the cycling of carbon and nitrogen in the soil is dependent on the ratio of C:N.
Plant Nutrient Management in Hawaii’s soils
Conservation Practice Standard Nutrient Management (Code 590)
Soil Carbon Amendments – Additions of high carbon products increase the carbon present in a soil or can sustain current levels by replacing carbon lost due to oxidation from cultivation. Soil carbon increases water and nutrient holding capacity. The C:N ratio of added amendments should be below 30:1 to avoid immobilization of nutrients.
Conservation Practice Standard Soil Carbon Amendment(Code 808)
Windbreaks – Alter the microclimate experienced by your crops and can reduce evapotranspiration, conserving soil moisture which enhances soil biology.
Trees and Shrubs for Windbreaks in Hawaii
Conservation Practice Standard Windbreak-Shelterbelt Establishment and Renovation (Code 380)

Sourcing Carbon

Incorporating organic matter can improve the physical, chemical, and biological properties of soil. Sourcing local organic matter can be a challenge.

Commercial Composting Facilities on Hawaiian Islands –
Suppliers of compost, soil mixes, and mulch approved by the Department of Health are listed here. Quality and availability may vary by supplier and location.
Island Commodities –
Oahu based producer of meat and bone meal by products with an average carbon to
nitrogen ratio of 5:1. Call (808) 682-5844 for availability.
On Site Composting –
Repurposing green waste or farm by-products into compost can be done on site through many methods. A method overview by University Hawaii is linked here.

Windward Zero Waste School Hui offers excellent guidance and resources for vermicomposting. They sell finished compost as well as worms on Oahu. It is against the law to import worms into Hawaii, so please purchase worms from local purveyors only.

University Hawaii Publications, Researchers, and Extension Agents

University of Hawaii, College of Tropical Agriculture and Human Resources promotes the success of Hawai`i’s agriculture, strong and healthy communities, and sound stewardship of Hawai‘i’s land and natural resources. Their publications are publicly available and easily found through internet searches, though faculty webpages are the best place to visit for news on current research efforts and publications.

University Hawaii Soil Nutrient Management – Explains fundamental concepts for managing nutrients in tropical soils with sections on soil basics, soils of Maui, and Nutrient Management.
University Hawai’i Sustainable and Organic Agriculture Program – Extensive collection of publications on cover crop species, compost, and more.
College of Tropical Agriculture and Human Resource Publication Search – The CTAHR publications database reflects over a century of study by researchers and
extension agents. Selected Publications –

Soils faculty at UH Mānoa

Dr. Jonathan Deenik, Department Chair – Soil Fertility and Management

Dr. Susan Crow, Associate Professor – Soil Ecology and Biogeochemistry

Dr. Noa Lincoln, Assistant Professor – Indigenous Crops and Cropping Systems

Dr. Nhu Nguyen, Associate Professor – Soil Microbial Ecology and Symbioses

Dr. Hue Nguyen, Professor of Environmental Soil Chemistry

Dr. Koon-Hui Wang, Associate Professor – Soil and Agroecosystem Health Management

University Hawaii CTAHR Cooperative Extension Agents

Non-profits & Funding Programs for Farmers Interested in Soil Health

These organizations provide training, events, and other services. Please visit their webpages for up-to-date information and opportunities.

GoFarm Hawaii – Statewide Beginning Farmer Training Program with sites on Oʻahu, Kauaʻi, Maui, and Hawaiʻi Island. Their mission is to enhance Hawaiʻi’s food security and economy by increasing the number of sustainable, local agricultural producers by providing hands-on commercial farm and business training.
Hawaiʻi Farmers Union United – Represents and advocates for farmers and ranchers on all of the Hawaiian Islands. Provides programs in farmer training, Hawaiian agricultural practices, and improving soil health, among others.
Hawaii Cattlemenʻs Council – Organization working for the cattle producers of Hawaii in areas of education, promotion, and research.
Oahu Resource Conservation and Development Council – Offers grant funded training for farmers, support for in-field research on soil management practices, cost share on practice implementation for farms in current project areas, and develops farm conservation plans.
Oahu Agriculture and Conservation Association – Efforts focus on expanding knowledge, support for producers, and implementation of best management practices for conservation and agriculture. They offer grant/loan application assistance and mini-grants to participants in their Together We Farm program.
The Kohala Center – Their mission is to respectfully engage the Island of Hawai‘i as a model of and for the world through our work in the areas of energy self-reliance, food self-reliance, and ecosystem health. They are a source of soil health knowledge and also facilitate business planning.
USDA Natural Resource Conservation Service (NRCS) – NRCS offers technical and financial assistance to help producers plan and implement conservation practices.

This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2019-38640-29880 through the Western Sustainable Agriculture Research and Education program under project number OW20-354. USDA is an equal opportunity employer and service provider. 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.