Using green seaweed (Ulva spp.) as a soil amendment: Effects on soil quality and yield of sweet corn (Zea mays L.)

View the project final report

• 2011 annual report
• 2012 annual report

Commodities

• Vegetables: sweet corn

Practices

• Crop Production: organic fertilizers
• Education and Training: extension, on-farm/ranch research
• Farm Business Management: budgets/cost and returns, feasibility study
• Natural Resources/Environment: biodiversity
• Production Systems: organic agriculture
• Soil Management: organic matter, soil analysis, soil chemistry, soil microbiology, soil quality/health
• Sustainable Communities: local and regional food systems

Application of seaweed as a soil fertility management strategy is a traditional practice in many coastal regions, utilizing an inexpensive, abundant, nutrient-rich resource, and often supporting diversified, sustainable agriculture. In this study, I will investigate the application of this practice in coastal New England. The use of excessive beach-cast green seaweed biomass may address the problems of reliance on increasingly expensive inorganic fertilization, accumulation of problematic seaweed biomass, and maintenance of soil fertility and quality. To assess the production result obtained by initiating seaweed amendment as a soil fertility management practice, I will compare the yield of sweet corn (Zea mays L.) in response to soil amendment with either inorganic fertilizer or green seaweed (mostly Ulva spp.) collected from bloom-impacted sites. Additionally, I will evaluate the effects of seaweed amendment on diverse soil physical, biological, and chemical parameters important for agricultural productivity, maintenance of soil quality, and associated conservation of soil resources. To explore the feasibility and viability of adopting seaweed use in agriculture, I will evaluate benefits, limitations, and economic considerations related to the practice, and assess the role of seaweed amendment in long-term, whole-farm soil fertility management plans. The results of this study will be disseminated through University of Rhode Island Cooperative Extension, academic, and farm education venues, sharing a potential means for farmers to reduce costs, improve soil fertility, enhance environmental stewardship efforts, and increase sustainable use of local resources.

1) Characterize and prepare suitable amendment material from raw green seaweed biomass for field application.
2) Evaluate the effect of seaweed amendment on the yield (bushel/acre and biomass/cob) and quality of sweet corn, an economically important crop for local agricultural production, in comparison to a conventional inorganic fertilization treatment. This objective will address the hypothesis that sweet corn yield and quality is at least equal in seaweed-amended plots in comparison to inorganically-fertilized plots due to the provision of plant nutrients and improvement of diverse soil quality parameters.
3) Evaluate seaweed amendment effects on physical, chemical and biological soil quality parameters in comparison to a conventional inorganic fertilization treatment. Hypothesized effects of seaweed
amendment on soil quality parameters are summarized in Table 1 (Attachments).
4) Assess the economic and practical feasibility of seaweed amendment for sustainable agriculture in coastal New England through synthesis of experimental findings, both from this and previous studies, and
through discussions with local agriculturalists, Extension agents and agricultural economists. This will allow for evaluation of how this practice may be incorporated into long-term soil fertility and whole-farm management plans.