Reducing Pacific Island Growers' Reliance on Off-island Fertilizer Sources Through Improved Awareness and Efficient Use of Local

Reducing Pacific Island Growers' Reliance on Off-island Fertilizer Sources Through Improved Awareness and Efficient Use of Local

Summary

Replacing imported fertilizers with local resources is the highest priority identified by the participants of the Western SARE Hawai’i Subregional conference. Lab and greenhouse experiments were conducted to screen locally produced composts and fertilizers for their N release and plant growth response (Please see results section for more details). Periodically, samples from Island Commodities has been collected to quantify their nutrient content and measure stability of the product over time. Samples of major algae invasive species were collected periodically and analyzed for their potassium content. Research is on-going on other objectives/activities of this project.

Objectives/Performance Targets

1. Enhance the capacity of at least 300 growers, compost producers, and other agricultural professionals in Hawaii, American Samoa, and elsewhere to evaluate compost quality.
2. Identify the most important variables influencing the effect of rendered meat products (tankage) on plant growth and mineral nutrition in Hawaii and American Samoa.
3. Quantify the independent and interactive effect of species, collection location, and simple processing on nutrient content and availability of three algae species collected from multiple sites on Oahu, Molokai, and Hawaii islands.
4. Ensure dissemination of information from this project to producers and agricultural professionals throughout the Pacific region beyond the project duration.

Accomplishments/Milestones

• Master degree student Plan-A (Jeana Cadby) completed her degree with partial help from the project. She conducted two field trials using algae applied at different application rates on sweet potatoes growth and yield. Also, the student wrote a thesis (citation below and full thesis file is attached).
• PhD student (Chandrappa Gangaiah) completed data analysis of two previous greenhouse experiments to examine the effect of algae species applied at different application rates on Chinese cabbage growth response and potassium tissue uptake.
• PhD student developed his PhD proposal based on the previous data analysis (PDF copy of the proposal presentation is included).
• Validated previous lab experiment results in a fish pond with ocean water, focused on reducing viability of seaweed species in collaboration from the Super-Suckers team of the Department of Land and Natural Resources. The experiment is included in the master student thesis.
• Completed lab mineralization/leachate column study using tankage applied at different application rates under two different soils. High school student (Roshani Jha) is presenting part of the tankage mineralization/leachate experiment data in Hawaii State’s Science Fair competition.

PUBLICATIONS

Peer-reviewed articles and book chapters:

Amjad. A. Ahmad, N. V. Hue, and Theodore J.K. Radovich. 2014. Nitrogen release patterns of some locally made composts and their effects on the growth of Chinese cabbage (Brassica rapa, Chinensis group) when used as soil amendments. Compost Science & Utilization 22(4): 199-206.

Radovich, T., A. Pant, A. Ahmad, C. Elevitch, and N. Hue. 2014. Enhancing soil function and plant health with locally available resources. Book Chapter In: Food-Producing Agroforestry Lanscapes of the Pacific (Series). Hawaii, USA.

Graduate Student Thesis:

Jeana Cadby. 2014. The effect of invasive seaweed (Eucheuma spp.) and tankage, as a soil amendment, on sweet potato growth in two Hawaiian soils. Master Thesis. University of Hawaii at Manoa.

• Master student (Jeana Cadby) full thesis
• Chandrappa Gangaiah_PhD proposal presentation

Impacts and Contributions/Outcomes

1-Local fertilizer producers report improved knowledge of product quality.

2-Utilizers of algae, tankage, and compost are incorporating project recommendations into their operations.

3-Biosecurity protocols have reduced concerns of algae spread to other areas.

Collaborators: