by Christian Schmalz, MBA Marketing Director, UlexAndes-USA

Seaweed (kelp) remains a scientifically proven natural, cost-effective, biodegradable agri-input that has consistently improved agriculture crop health and yields. Seaweeds contain major and minor nutrients, trace elements, alginic acid, vitamins, auxins, gibberellins and cytokinins in balanced proportions optimal for plant absorption. Combination products may be the future in kelp extract fertilizers; given the vast amount of seaweed species yet to be investigated.


The benefits of kelp forests have been known and utilized long before Charles Darwin compared species in 1909. Because of their diverse evolution, complex structure and high impact on marine coastline ecosystems, they continue to populate research studies from a diverse range of scientific fields. Their importance in agriculture also continues to be studied as the well-supported benefits of kelp extract fertilizer continue to challenge scientists to explain and differentiate specific biochemistry interactions.

Economically, kelp has played a significant role in the lives of maritime people for millennia. Distribution, and therefore production of kelp forests for harvesting, is physiologically constrained by light, nutrient-rich boundary currents and sea temperature consistent with global latitudinal distributions. Emerging markets, especially the Asia-Pacific region that has traditionally dominated the kelp food supply sector, have heavily invested in the technology necessary for new market entry into biomaterials and agrichemicals. One report suggests that scientific publications and seaweed product patents have both experienced >10% growth since 1990.


Seaweeds are classified into three broad groups based on their pigmentation: Phaeophyceae (brown), Rhodophyceae (red) and Chlorophyceae (green).

A review of kelp extract fertilizers currently available in todays agriculture marketplace reveal that it is dominated by Phaeophyceae, the brown algae species, which are commonly located in colder waters. It is reported there are over 1500 species of brown algae in a variety of sizes. Laminaria, often described as giant kelp, grows up to 60m in length in large underwater forests. This type of brown kelp is one of the few with the ability to be cultivated. Ascophyllum nodosum, arguably the predominate seaweed available for agriculture use, can reach two meters in length and is commonly found attached to rocky coastlines in the northern Atlantic Ocean; including the north-western coasts of Europe, and north-eastern coast of North America.

While most brown algae species thrive in colder water exposed to active, nutrient-heavy boundary currents, numerous species can be found in more temperate oceans. Sargassum, named from Portuguese sailors in the Sargasso Sea, and described by Columbus as gulfweed, can be found covering beaches, attached to sub-tidal coral or rocks in sheltered areas of the Atlantic Ocean. Ecklonia maxima is also typically found growing in shallow forests in the temperate areas of the southern oceans, primarily the southern Atlantic Ocean coast off Africa. Seaweed extract fertilizers also contain small levels of natural plant growth regulators


“Secret sauce”

The biochemistry makeup of seaweed is the ‘secret sauce’ that enables for efficient transfer of nutrients between plants and soils. Alginic acid (alginates), a major content of liquid seaweed extract fertilizers, is a polysaccharide widely distributed throughout the cell wall of seaweeds contributing to the flexibility of the kelp. It decomposes more readily than cellulose to stimulate soil microorganisms, resulting in improved water holding capability of soils and crumb structure formation. Alginates from different species of brown seaweed vary in their chemical structure. Seaweed extract fertilizers also contain small levels of natural plant growth regulators (cytokinins, gibberellins, auxins). Recently, UlexAndes-USA completed a project comparing a combination seaweed extract fertilizer product (sargassum and ascophyllum nodosum) against established individual seaweed and synthetic products widely available in the agriculture marketplace. Ascophyllum nodosum, arguably the predominant seaweed available for agriculture use, is commonly found attached to rocky coastlines in the northern Atlantic


Laboratory Analysis quantified acetic acid (IAA), indole-3-butyric acid (IBA) and gibberellic acid (GA3) in seaweed samples using UPLC/MS through an independent, well-respected laboratory. A quantification method was developed for subsequent use of the method on sample sets provided by the sponsor. Water was used for calibration curve generation and to determine detection limits and recovery. The UPLC-MS system (ACQUITY UPLC-Quattro Primer XE MS, Waters Corp., Milford, MA) was used for seaweed sample analysis. The TargetLynx application manager (Waters Corp., Milford, MA) was used for data analysis.

Indol-3-acetic acid (IAA) is the active auxin (phytohormone) in seaweed kelp extracts.

Auxins are a class of plant hormones that have been extensively studied concerning their impact on a plethora of developmental processes during the plant’s life cycle.

Indole-3-butyric acid (IBA) is recognized as an auxin precursor or storage form. Scientists suggest only a small fraction of (IAA) exists as free or active. Much of the auxin ‘pool’ exists as this inactive precursor, which may exist to regulate the auxin homeostasis. Gibberellic acid (GA) is another phytohormone involved in most aspects of plant cell growth and development. Gibberellic acid is very potent growth regulator that is applied in low concentrations due to the paradoxical reaction that may occur with over-application.


Field trials on select crops, including cherries, potatoes, tree fruits and alfalfa. The use of AUXANO™ showed very positive effects. For example, single drop potato tubers were “dipped” with AUXANO™ in addition to a foliar feed schedule. AUXANO™ treated plots increased #1 potatoes by 14% and #2 potatoes 13% over the controls and increased the solids by 2%. Overall, yield was increased by 41%. The impact on cherries resulted in a 2.6% increase in higher pack out, a 35% Brix increase, increased micronutrient levels, and a 6.6% increase in 9-10 row sizes. The other trials exhibited similar crop specific results.