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. Lab, greenhouse, and field (including on-farm) trials were conducted to produce high quality liquid organic fertilizer for fertigation purposes. A recipe was developed and its quality was evaluated in a series of field trials (including on farm) to produce vegetable crops and a series of greenhouse trials to improve seedlings quality of vegetable and fruit crops. Workshops/field days and public talks were given to disseminate the project findings. A book chapter and an extension bulletin were produced.
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 20-35oC).
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.
Over 85% of our food in the Pacific islands is imported, with stores having less than a 7-day supply at any given time. Cost of imported fertilizers were tripled between 2006 and 2008 and is expected to increase. This has increased the demand for locally produced organic fertilizers, food security, and ensuring a cost effective, stable source of agricultural inputs. Organic amendments release nutrients over a relatively long time. This slow release of nutrients reduce N losses and builds soil fertility over long term application. However, they may not meet the crops demand for nutrients. Water scarcity is a worldwide issue, and it’s a growing concerns in the Pacific Islands. Farmers have adopted drip irrigation and this has improved profitability by increasing crop yield, quality, and reduced production cost. Crops need multiple applications of fertilizers, especially at the peak uptake growth stages. Fertigation via drip is a highly recommended technique to apply both water and nutrients. It allows for uniform and proper application of nutrients within the wetted areas and reduce water and nutrient losses. Nitrogen is one of the most limiting nutrient for plants growth and yield, and can be easily measured by commercially available electrodes. Tankage (meat and bone meal by products) is a high nitrogen (9%) content fertilizer, approved for agricultural uses, produced locally, and under high heat, which reduce chances of pathogen growth (Random samples of the produced soluble fertilizers will be submitted for pathogen content analysis). It’s known that nutrient release from organic fertilizers are mainly due to biological and environmental factors. In addition, aerated (brewed) compost tea is proven to have higher nutrient availability and content. This project focused on elucidating the processes (biology and chemistry) and other factors (covering, aeration, time, and temperature) of nutrient release from local, relatively cheap inputs, and on evaluating the quality of the produced aqueous solutions on crops and soil fertility, especially under drip and mulching conditions for different Hawaiian soils.
Objective 1: Identifying optimal temperature, time, chemical, and biological factors to maximize mineralization and aqueous extraction of N from tankage;
Activities include: Develop and validate procedures to enhance the extracts of Nitrate (NO3-N) and Ammonium (NH4-N) from tankage:
For objective # 1, in the three activities below, same experiment setup will be used, only different materials will be tested. In each experiment, 4 grams of tankage and 200 ml of deionized water will be placed in 250 ml flask. The ratio of 1:50 (tankage:water) is used here to ensure that nitrogen release will not be affected by the build-up/increase nitrogen concentration in the soluble solutions. All experiments will be arranged in a Complete Randomized Design (CRD) with 3 replicates. Samples will be filtered using Fisher filter papers and nitrogen (NO3-N and NH4-N) concentration will be measured using Vernier electrodes. At each sampling time, calibration equations will be developed using known NO3-N and NH4-H content solutions, and few random samples will be submitted to the University of Hawaii’s ADSC (Agricultural Diagnostic Service Center) laboratory for quality assurance of NO3-N and NH4-N content. The best treatment from each activity will be used to conduct a factorial experiment in CRD to measure the interaction effects on nitrogen release.
NOTE: Sub-samples of the produced soluble solutions will be tested for STEC and non-STEC pathogens content.
1) Chemical and Biological: Different materials (baking soda, vermicompost, molasses, and yeast) will be tested for the chemical and biological effects on nitrogen release from tankage. All the materials will be used in small quantities. Prior to that, separate quantity (0.01, 0.1, 0.5, and 1.00 gram) experiments will be conducted to evaluate and set standards for each material;
2) Covering and Aeration: A set of experiments will be conducted to evaluate the effect of covering on release/accumulation of NO3-N and NH4-N in the soluble solutions. Air pumps will be used to test the effect of aeration on nitrogen release. This set of experiments will be conducted for each material separately (due to limited number of air pumps), where air will be provided through pipes at different time intervals (0, 8, 16, and 24 hours); and
3) Time and Temperature: Different time intervals (0, 4, 8, 24, and 48 hours) will be tested for the effect on nitrogen release. Temperature of 20oC (lab temperature) and 35oC (oven), and time between 0 to 48 hours (interaction). In this activity, Laboratory oven will be used. Each treatment will be replicated 6 times (3 in oven and 3 will be placed on lab bench). At initial (zero) time, deionized water at 20 and 35oC will be used, where water and tankage will be mixed and samples will be filtered immediately after.
Objective 2: Developing yield response curves and recommendations to optimize aqueous solution for greenhouse and field applications,
1) From objective # 1 results, the best solutions will be tested in a series of greenhouse and field experiments to evaluate the quality of the produced soluble fertilizers compared to synthetic and organic aqueous solutions available in the local markets. Different crops will be tested (e.g. eggplant, beets, and beans, in the greenhouse trials), and taro, papaya, and eggplant (growers-managed farms). Randomized complete block design with three replicates will be used for each experiment. Seedlings will be produced in separate trays. Two weeks after, seedlings will be transplanted into bigger pots filled with peat moss. The same soluble fertilizers (treatments) will be tested in seedlings and after transplanting stages. Leaf chlorophyll content will be measured weekly using SPAD meter (Minolta SPAD 502), and fresh and dry weights of plants will be recorded at harvest time.
2) The results from previous greenhouse experiments will be validated through a series of on-farm field trials. Different soils will be evaluated on different Hawaiian Islands (Oahu, Big Island and Molokai). Same soluble fertilizers (treatments) will be tested, and Papaya, Taro, and Eggplant crops growth and yield will be evaluated.
3) Develop recommendations for local farmers using the previous results. Recommendations for greenhouse and field applications, through different extension media, will be developed based on the crops response curves and data analysis.
Objective 3: Disseminate the project findings, among local producers, extension agents, NRCS planners, and other university professionals, through a series of workshops and field days, extension bulletins, production procedure manual, and other online resources.
Activities include: (Please see producer adoption section for more information about extension agents/farmer to farmer extension plan).
1) At least 3 on-farm workshops and field days to be conducted on different Hawaiian Islands (Oahu, Molokai, and Big Island) to transfer the project findings among the local community, where study findings will be presented.
2) At least 2 Extension bulletins and a short manual for solution fertilizer production procedures will be developed and distributed among local farmers. Technology transfer efforts will focus on the methodologies that used in this project to produce the soluble solutions and the crops response to the application of the fertilizers. Websites to which materials will be posted include: SOAP: http://www.ctahr.hawaii.edu/sustainag/index.html; eXtension: http://www.extension.org.
3) At least 2 scientific peer reviewed publications to be produced in the last year of the project, developed based on the data collected from production procedures, application (greenhouse and field trials), and crops growth response.
Note: Cost analysis of solution fertilizers production will be conducted throughout all activities.
Completed all lab trials to evaluate different factors (time, temperature, open and closed condition, and chemical/biological agents) to enhance the release of nitrate (NO3-N) from the solid materials into the solution.
Application recipe was developed and used in comparison with liquid synthetic fertilizer (the application of both liquid fertilizers was based on the NO3-N concentration in the solution).
Completed field trials for pak choi, lettuce, daikon, kai choi, and turnip crops. All crops were repeated twice to validate the results of first round.
Completed five greenhouse trials for sweet corn, tomato, chili pepper, papaya, and coffee seedling using the liquid organic fertilizer, liquid synthetic fertilizer, and water only as control to improve seedlings quality.
Completed chemical tissue analysis for crops and seedlings harvested from the field and greenhouse trials through ADSC (Agricultural Diagnostic Services Center) at the University of Hawaii.
Completed On-Farm field trials with two collaborators: Jared Davis (Molokai Island) and Mark Hamamoto (Oahu island) for 2-acre application of liquid organic fertilizers under different vegetable crops.
Publish a book chapter in an open access publisher to ensure easy access to it. The chapter included details about the materials used in producing the liquid organic fertilizer, recipe, and results of the application from the field trials.
Published one extension bulletin including details of the materials, methodology, recipe, application, and results from the lab and field trials.
Five field days/workshops were conducted, on different Hawaiian islands, combined with other WSARE funded projects to disseminate the project findings among local farmers and community, extension agents, university researchers/educators, and other ag professionals.
Five guest lectures were given: 2 to classes at the University of Hawaii (Vegetable crop production and Organic Food Crop Production) and 3 to training programs (GoFarm, Student Organic Farming Training, and New Beginner Farmers).
The recipe is new/novel by its nature of using local materials. So, for the adoption percentage calculation, we considered any farmers applying the recipe in their operation as increased percentages from none (0%) due to no previous use of the recipe was recorded. Adoption increase percentages were measured by quantifying number of participants in each field day/workshop (as total number), and the answer to a question about the use of the recipe in their operation.
1-Increased 10% among long term crops farmers who are incorporating the project produced recipe to meet the immediate need of crops to nutrients (especially nitrogen).
2-Increased 15% adoption among local farmers who are utilizing the recipe to improve seedlings quality of different vegetable and fruit crops. Improving seedlings quality is important to start with stronger plants, a uniform field, and it’s expected to lead for higher yield.
3-Increased awareness of 50% among local ag-production companies about the benefits of quality control in their operation and the importance of meeting the local market demand on the state ag production and economy.
4-Increased 50% adoption among local training organizations (such as GoFarm, New beginner Farmers training, and Master Gardeners) of the recipe in their training materials and field application of the recipe, especially under organic farming.
5-Its expected that the impact/outcomes of this project will last and continue beyond the project duration and to be incorporated into other projects as well.
Educational & Outreach Activities
Ahmad, A.A., T.J.K. Radovich, H.V. Nguyen, J. Uyeda, A. Arakaki, J. Cadby, R. Paull, J. Sugano and G. Teves. 2016. Use of Organic Fertilizers to Enhance Soil Fertility, Plant Growth, and Yield in a Tropical Environment. In: M.L. Larramendy and S. Soloneski, (eds.), Organic Fertilizers-From Basic Concepts to Applied Outcomes. Chapter 4, p: 85-108. http://www.intechopen.com/books/organic-fertilizers-from-basic-concepts-to-applied-outcomes.
Amjad Ahmad, Theodore J.K. Radovich, Nguyen V. Hue, and Alton Arakaki. 2014. Producing High Nitrogen Liquid Fertilizer for Fertigation Purposes. HanaiAi newsletter. http://www.ctahr.hawaii.edu/sustainag/news/articles/V19-Ahmad-Nfertigation.pdf
Amjad A. Ahmad. 2016. Local Fertilizer Research Updates. Sustainable and Organic Agriculture Program’s Extension and Research Update. Nov. 9-10, Waimanalo Research Station, University of Hawaii at Manoa, Hawaii.
Amjad A. Ahmad. 2016. Advancing Sustainable Farming in Hawaii: Soil Fertility and Crop Diversity. Seminar series, Department of Tropical Plant and Soil Sciences. University of Hawaii at Manoa, Oct. 7, Honolulu, Hawaii.
Amjad A. Ahmad, Theodore J.K. Radovich, Hue V. Nguyen. 2016. Pros and Cons of Locally Produced/Available Organic Fertilizers. Cover Crops and Soil Health Field Day, June 21st, Waimanalo Research Station, Oahu, HI.
Amjad A. Ahmad, Theodore Radovich, Jensen Uyeda, Nguyen Hue, Alton Arakaki, Jari Sugano, Glenn Teves, Chandra Gangiah, Ian Gurr, Arnold Berek. 2016. Improving Soil Health, Plant Growth, Yield, and Quality with Local Fertilizers. Go-Farm Training, June 7, Waimanalo Research Station, Oahu, HI.
Theodore Radovich, Amjad A. Ahmad. 2016. Soil Health and Organic Practices. Organic Farming & Soil Health Workshop. Kahumana Center, June, 4, Waianae, HI.
Amjad A. Ahmad, Theodore Radovich, Jensen Uyeda, Jari Sugano, Alton Arakaki. 2016. Soil Health and Locally Produced Fertilizer Inputs. Edible Crops Conference. May 24. Turtle Bay, Kahuku, HI.
Amjad A. Ahmad, Theodore Radovich, Jensen Uyeda, Nguyen Hue, Alton Arakaki, Jari Sugano, Glenn Teves, Chandra Gangiah, Ian Gurr, Arnold Berek. 2016. Local Inputs for Organic Farming in Hawaii. Master Gardener Training. April 13. Kauai, HI.
Amjad A. Ahmad, Jensen Uyeda, Theodore J.K. Radovich. 2015. Local Organic Fertilizers for Better Yields and Fertile Soils. AgPro Workshop. Oct. 13-14, Maui College/Cooperative Extension Services, Maui, Hawaii.
Amjad A. Ahmad and Theodore J.K. Radovich. 2015. Producing Liquid Fertilizers from Solid Organic Sources. Organic Agriculture Workshop on Oahu (Aug. 29) and Maui (Sept. 19), Hawaii.
Amjad A. Ahmad, Hue V. Nguyen, Theodore J.K. Radovich. 2015. Enhancing Nitrogen Availability in Liquid Fertilizers Derived from Solid Organic Sources for Fertigation. HorScience 50(9): S222. ASHS Annual Conference, Aug. 4-7. New Orleans, Louisiana.
Amjad A. Ahmad, Theodore J.K. Radovich, Nguyen V. Hue, Alton Arakaki, Glenn Teves, Jari Sugano, Jensen Uyeda. 2015. Local Sources of Soil Fertility. Western Sustainable Agriculture Research and Education (SARE) Agroforestry Workshop Series. June 12-13 on Maui, and 20-21 on Kona, Hawaii.
Amjad A. Ahmad, Theodore J.K. Radovich, 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, 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.
2016: Sustainable and Organic Agriculture Program’s Extension and Research Update (Field day presented results of the liquid organic fertilizer application on taro and papaya plots at Waimanalo Research Station)
2016: Advancing Sustainable Farming in Hawaii: Soil Fertility and Crop Diversity (Departmental Seminar). Included demos of the preparation/application methods (showcase of ingredients, brewing materials, and field injection tools) of the liquid organic fertilizer recipe.
2016: Cover Crops, Soil Health, and Soil Fertility (Field day at Waimanalo Research Station). Included showcase of the recipe preparation/injection into drip irrigation lines.
2016: Improving Soil Health, Plant Growth, Yield, and Quality with Local Fertilizers. Guest lecture for Go-Farm Training program. Included demos of the preparation and field application of the liquid organic fertilizer to both program participants and crew on Oahu Island.
2016: Local Inputs for Organic Farming in Hawaii. Master Gardener Training (Guest lecture). Included field demos of preparation and field application of the liquid organic fertilizer recipe on Kauai Island.
2016: Local Organic Fertilizers for Better Yields and Fertile Soils. AgPro Workshop. Included demos of field preparation and application of the liquid organic fertilizer on Maui Island.
2015: Organic Agriculture Workshop/field day on Oahu (Aug. 29) and Maui (Sept. 19). Included demos of preparation and application methods of the liquid organic fertilizer on both Islands and field results (vegetable crops were growing under liquid organic and liquid synthetic application at Poamoho Research Station-Oahu only).
2015: Western Sustainable Agriculture Research and Education (SARE) Agroforestry Workshop Series. Covered 5 Islands in Hawaii, included demos of liquid organic fertilizer preparation and field application methods and results. Also included on-farm visits (tours) to farmers who adopted the recipe in their operation (such as Mark Hamamoto on Oahu Island and Jared Davis on Molokai Island).
To be completed in the near future:
1-A peer-reviewed journal article that was delayed due to some technical issues with tissue chemical analysis.
2-An extension bulletin and short manual were delayed due to the initial plan of including the greenhouse/seedlings data.
Simple Cost-Benefit analysis were conducted using the results obtained from the field trials . Comparing the locally produced liquid organic fertilizer (recipe from this project) to the liquid organic fertilizer from the market showed a slight increase in the benefits from using the locally produced liquid fertilizer. However, other factors (such as waste management benefits and environmental protection benefits) were not included since they have no actual value to be added into the analysis.
Also, Cost-Benefit analysis were conducted to compare the liquid organic fertilizer (from this project) to the liquid synthetic fertilizer (used as comparison in this project). The analysis showed an increase in the production cost under the liquid organic fertilizer and that might be due to the high amount of materials (tankage + vermicompost) needed compared to the synthetic source which was small amount (tankage has about 10% N, Synthetic source has about 30% N).
Farmer participation/adoption was measured during each field day/workshops that was conducted between Jan. 2015-Dec. 2016. At the end of each workshop/field day, surveys were distributed and the results (participants answers) were evaluated to measure adoption level among farmers and other stakeholders. In each field day/workshop, number of participants varied between 30-75 participants. There was a total of ~500 participant who completed surveys and included their contact information to be included in the listserv of the Sustainable and Organic Farming program. Also, the project included extension specialist (Theodore Radovich) and at least one extension agent on each island to ensure a well dissemination of the project findings.
1-Long term crops farmers are incorporating the liquid organic fertilizer recipe in their operations in order to meet the immediate need of crops to nutrients (especially nitrogen).
2-Farmers are utilizing the recipe to improve seedlings quality of different vegetable and fruit crops. Improving seedlings quality is important to start with stronger plants, a uniform field, and it’s expected to lead for higher yield.
3-Increased awareness among local ag-production companies and training organizations. (Go-Farm) is incorporating the liquid fertilizer recipe into their operations and training materials.
Areas needing additional study
1-Number of extracts from each batch using the recipe needs to be studied in order to evaluate quality of the produced liquid fertilizer each extract, plant growth response, improve waste management, and to reduce the production cost. Currently, the project PIs are recommending the farms/users of the recipe to use the leftovers from each batch as solid fertilizer or to be mixed with peat to improve seedling media quality.
2-Currently, vermicompost and aeration were found to be the best agents (factors) in improving the liquid organic fertilizer quality. However, passive (non-aerated) methods were not tested, which is important for farms with no or limited access to electricity.
3-Tankage was the main and only nitrogen source used for the purpose of this project. However, there are other locally produced materials with lower nitrogen content that need to be tested.