High nutrient solution fertilizers derived from local organic inputs for field and greenhouse application in the tropics

High nutrient solution fertilizers derived from local organic inputs for field and greenhouse application in the tropics

Summary

Replacing imported fertilizers with local resources is the highest research and educational priority identified by stakeholders throughout the Pacific at multiple meetings. While progress is being made in developing recommendations for locally produced solid fertilizers, the need for solution fertilizers derived from local resources has not yet been adequately addressed. This is especially true for growers of long term food crops, such as taro and fruit trees, who need to provide supplemental nutrition throughout the cropping cycle. The production of locally derived nutrient solutions for fertigation will keep local farmers competitive, reduce water-use and loss, and protect the environment by reducing chemical use. Anecdotes from innovative growers and preliminary findings in the lab has shown that locally produced tankage (rendered meat, 9% N) was a good source of soluble nitrogen (NO₃-N and NH₄-N). At lab scale, some treatment effects on nitrogen release from tankage were tested. The preliminary results are promising, although there is a need to evaluate more treatments and increase scale in order to come up with recommendations for local farmers. The goal of this project is to develop capacity among Pacific Island growers to cost effectively produce concentrated nutrient solutions from local materials, accelerating current efforts to reduce grower reliance on imported fertilizers.

Objectives/Performance Targets

Objective 1: Identifying optimal temperature, time, chemical, and biological factors to maximize mineralization and aqueous extraction of N from tankage.

Activities: Develop and validate procedures to enhance the extracts of nitrate (NO₃-N) and ammonium (NH₄-N) from tankage using factors, such as:

1) Chemical and Biological (Baking soda, vermicompost, molasses, yeast).

2) Covering and aeration (cover/no cover, and aeration/no aeration).

3) Time and temperature (Time intervals 0-48 hours and 20-35^oC).

Objective 2: Developing yield response curves and recommendations to optimize aqueous solution for greenhouse and field applications.

Activities: Develop and validate greenhouse and field application recommendations to local farmers and producers through:

1) Series of greenhouse trials (to test quality of highest nitrogen soluble solution).

2) Series of on-farm trials (to evaluate laboratory and greenhouse trials results).

3) Evaluation of results (Develop greenhouse and field application recommendations).

Objective 3: Disseminating the project findings among local producers, extension agents, and other university professionals, through a series of workshops and field days, extension bulletins, production procedure manual, and other online resources.

Activities include: Transfer the project findings among local farmers and other professionals through:

1) At least three on-farm workshops and field days to be conducted on different Hawaiian Islands (Oahu, Molokai, and Big Island).

2) At least two Extension bulletins and a short manual for solution fertilizer production procedures.

3) At least two scientific peer reviewed publications.

Note: Cost analysis of solution fertilizers production will be conducted throughout all activities.

Accomplishments/Milestones

• Twenty lab experiments were conducted to examine the effect of different factors/agents (single factors: Time, Temperature, Cover, Chemical, and Biological) on enhancing the release of nitrogen from Tankage (Meat and Bone Meal By-Products) into the liquid fertilizers produced.

• Ten lab experiments were conducted to examine the effect of different combinations of multi-factors on enhancing the release of nitrogen from tankage into the liquid fertilizers.

• A recipe was achieved with the highest nitrogen content in the liquid fertilizer.

• Validated previous lab results/recipe in an on-farm field trial on Molokai Island at the collaborator’s (Jared Davis) property for watermelon crop.

• Replicated field trial was conducted/still on-going at Poamoho Research Station to evaluate the achieved recipe on pak choi, lettuce, daikon, turnip, sweet corn, and other crops to be considered soon. The recipe is compared to a synthetic liquid fertilizer of 30-10-10.

• One extension bulletin and three public presentatation were given by the project PI/Co-PIs about the project activities and findings so far.

Extension bulletin: Amjad Ahmad, Theodore J.K. Radovich, Nguyen V. Hue, and Alton Arakaki. 2014. Producing High Nitrogen Liquid Fertilizer for Fertigation Purposes. HanaiAi. http://www.ctahr.hawaii.edu/sustainag/news/articles/V19-Ahmad-Nfertigation.pdf

Public presentations:

Amjad A. Ahmad, Theodore J.K. Radovich, and Nguyen V. Hue. 2015. Local Inputs to Enhance Soil Fertility and Plant Growth in Agroforestry Systems. Western Sustainable Agriculture Research and Education (SARE) Agroforestry Workshop Series. March 21 on Molokai and April 25-26 on Kauai, Hawaii.

Amjad A. Ahmad, Theodore J.K. Radovich, and Nguyen V. Hue. 2015. Using Locally-Produced Farm Inputs. Guest Speaker at the Molokai Native Hawaiian Beginning Farmer Program, Jan 29, 2015. Molokai Island, Hawaii.

• PDF file of presenatation given at the annual ASHS meeting

Impacts and Contributions/Outcomes

1-Increase interest among local farmers and ag companies regarding the liquid fertilizer production/use in their operations.

2-Utilizers of tankage and vermicompost are incorporating project recommendations into their operations.

3-Increase awareness among local farmers about the ability to produce the liquid fertilizer within their operation and apply with the drip irrigation for fertigation purposes.

Collaborators: