Seaweeds as Plant Fertilizer, Agricultural Biostimulants and Animal Fodder

Leonel Pereira, Kiril Bahcevandziev, Nilesh H. Joshi, Leonel Pereira, Kiril Bahcevandziev, Nilesh H. Joshi

• Publisher: CRC Press
• Year: 2019
• eBook ISBN: 9780429945113
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

The main effects of Seaweed extracts ( Ascophyllum, Fucus, Sargassum, Saccorhiza, Laminaria, Gelidium and others), when used as agricultural fertilizers, are better seed germination and higher quality fruit production, with longer shelf life; better use of soil nutrients; more productive crops and plants with greater resistance to unfavorable environmental conditions.

Algae also have a long history of use as animal feed. They have a highly variable composition depending on the species, collection season and habitat, and on external conditions such as water temperature, light intensity and nutrient concentration in water.

In relation to ruminal fermentation, a high variability of the digestibility values ??was found among seaweed species and cannot be attributed only to the composition of different nutrients of the algae. The role of marine algae for reduction of methane production is discussed with particular emphasis on novel algae-based feed strategies that target minimal methane emissions without affecting the functionality of the microbiota and overall animal productivity.

Key Features:

• Sustainable Agriculture
• Natural Feeding
• Nutrients Liquid Seaweed
• Agricultural Biostimulants
• Natural Pesticides

CHAPTER
1

Historical Use of Seaweed as an Agricultural Fertilizer in the European Atlantic Area

Leonel Pereira and João Cotas*

Marine and Environmental Sciences Centre (MARE), Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3000-456 Coimbra, Portugal

1 Introduction

The first documented use of seaweed as agricultural fertilizer in the European Atlantic Area occurred among the ancient Romans. L.J.M. Collumella, the most notable Roman writer on agricultural practices, wrote that roots were to be wrapped in seaweed in order to retain the freshness of the seedlings (Battacharyya et al. 2015). In AD 79, Pliny noted the gathering of “margo” (thought to be maerl, a red seaweed) by “peoples of Britain and Gaul” in order to fertilize their soils (Monagail et al. 2017). Seaweed was regularly used by ancient coastal people along the Atlantic to fertilize soil, but only the Romans have left written records of this practice.

The use of seaweed as fertilizer is known in several European maritime countries—in the North Atlantic, Iceland, Scandinavia and Baltic countries, Norway, Denmark, Orkney and Hebrides, Scotland, Ireland, the Aran Islands, the Channel Islands, Brittany, Spain and Mediterranean countries, in the Eastern Adriatic, Kirk Island (Bacelar 1953, Gavazzi 1974, Rasmussen 1974), and also in the Azores and Cape Verde (Medeiros 1967, Ferreira 1968). In Portugal, north of the Douro River it was practiced along the whole coast and was a normal and extremely frequent activity—and in some cases even a fundamental economic category. South of that river seaweed was used on a very small scale, near Peniche and in certain corners of the cliffs of Ericeira and Cape Espichel (Oliveira et al. 1990); on the Alentejo and Algarve coast, where the sea casts up enormous quantities of algae—the limos or the golfo—on to the rocks, they have never been practically used.

The cutting or collection of seaweed growing in the Iberian Peninsula or washed on to the beach—sargaço (see the main species of algae that constitute the sargaço and other traditional marine plants used in agriculture, in section 4), argaço (Basto 1910), or limos (Oliveira et al. 1990)—for fertilization of farm fields was certainly the most important of these agricultural and maritime activities, where tasks contributing to the crop developed in a natural setting that was often foreign to them, and where agriculture and fishing coexisted.

The production of algae depends on certain conditions, which are especially evident precisely in this area of our coast and in southern places—the coast must be fringed with rocks on which algae grow but from which the movement of surface waters during storms and tides can also pull them off; in fact, it is generally after storms and tides that more sargaço appears on the beaches. In order for this activity to be practicable, the coast must be accessible, and there must be wide sandy areas or available space for the collection and drying of algae—conditions that together are characteristic of the sea shore north of the Douro River, and that do not occur frequently south of this river (Oliveira et al. 1990).

2 Iberian Peninsula

2.1 The sargaço

The algae harvest in the Entre-os-Rios and the Douro regions (North of Portugal) was, from the Middle Ages to the mid-20th century, an economic and socially important activity in mainland Portugal, as is clearly demonstrated by the Dionysian and Manueline provincial laws of Póvoa de Varzim and Maia. In the provincial law published on March 9, 1308, granted to the old regiment of Varzim de Jusão and its terms, King D. Dinis determined that the privilege of collecting sargaço, as an economic activity of great importance at that time for fertilizing the land, belonged to its residents. These provisions were later confirmed in the Manueline Order of 1514 but, since it was a natural resource capable of generating revenue, the Order also established a tax on the sargaço trade (Pereira and Correia 2015).

In light of the close connection between algae and the way of life of a people, it is useful to distinguish the two main mixtures of marine algae traditionally used as fertilizer, that is, moliço and sargaço. Moliço is a mixture of green algae (Chlorophyta) and red algae (Rhodophyta), and also some marine plants. It is composed of specimens of the genus Enteromorpha (algae now belonging to the genus Ulva), Chaetomorpha/Rhizoclonium (Chlorophyta), Gracilaria and Ceramium (Rhodophyta), and seagrasses (angiosperms) belonging to the genera Zostera, Ruppia and Potamogeton (Figs. 1, 2 and 3), all harvested in Ria de Aveiro (Aveiro, Portugal) (see also sections 2.2 and 4).

Sargaço (also called “argaço” and “limos” since the time of the first kings of Portugal) is a mixture composed exclusively of several marine macroalgae (Saccorhiza, Laminaria, Fucus—Phaeophyceae, Codium—Chlorophyta, Palmaria, Gelidium and Chondrus—Rhodophyta) (Figs. 1 and 2), which grow on the rocks of the coastline (see also section 5). Traditionally, the algae washed on to the rocks on the seashore were collected and spread out on the sands to dry. The equipment used included the carrelo (used to transport the raft), the raft (used to reach the rocks furthest from the beach where the algae cling) (Figs. 4a, b), tools for cutting and collecting (foicinhão, croque, engaceira) (Figs. 4c, d), baskets made of wood splints (to pack and transport them to land), round mesh bags to collect loose sargaço from the water, and ox carts to transport them to the drying ground. Once they were dried, the sargaço was transported in the same baskets to the medas or haystacks (Figs. 4e, f). These haystacks were topped with straw to protect them from rain and sun (Pereira 2010a, Pereira and Correia 2015).

The harvesting of sargaço can be related historically, to a certain extent, with small holdings and intensive crops; it is in fact in these cases that the use of algae as fertilizer was especially effective and viable. And it was precisely these conditions that prevailed in the northern areas of the coast, where this activity had the greatest importance and where, in addition, the search for sargaço and cultivation of farm land were mainly carried out by families using their own labour (Oliveira et al. 1990).

To the north of the river Douro, this activity had characteristic and unique aspects. It was based on distinct sociological and economic conditions, which sometimes related to certain local patterns concerning gender-based division of labour, or the hybrid nature of the activity itself, in which a specific socio-professional evolution or mutation occurred. The gradual transformation of a form of family labour, a subsidiary of one’s own agriculture, into an autonomous commercial activity by people of other social categories who were recruited for it, and in the vast dune areas of Aguçadoura a well-defined movement of exploitation and valorization of the sands, began at the end of the 18th century. Intensive horticulture—the fields of maceira (Fig. 4g) typical of the region—is closely linked to this phenomenon, allowing it on the one hand and being increased by it on the other. In some cases, the activity of collecting and using sargaço was an essential factor of coastal settlement.

Figure 1. Main species used as agricultural fertilizer: Chlorophyta – a) Rhizoclonium linum, b) Codium tomentosum, c) Ulva sp.; Phaeophyceae – d) Ascophyllum nodosum, e) Bifurcaria bifurcata, f) Fucus serratus, g) Fucus vesiculosus, h) Himanthalia elongata, i) Laminaria digitata, j) Laminaria hyperborea, k) Pelvetia canaliculata, l) Saccharina latissima, m) Saccorhiza polyschides; Rhodophyta – n) Calliblepharis jubata, o) Chondrus crispus, p) Cryptopleura ramosa.

Color version at the end of the book

Figure 2. Main species used as agricultural fertilizer: Rhodophyta – a) Ceramium sp., b) Gelidium corneum, c) Gigartina pistillata. d) Halarachnion ligulatum, e) Lithothamnion corallioides, f) Lithothamnion glaciale, g) Osmundea pinnatifida, h) Palmaria palmata, i) Phymatolithon calcareum, j) Polyneura bonnemaisonii, k) Polysiphonia elongata, l) Vertebrata thuyoides.

Color version at the end of the book

Figure 3. Main species used as agricultural fertilizer: Marine angiosperms – a) Ruppia spp., b) Stuckenia pectinata, c) Zostera marina, d) Zostera noltei.

Color version at the end of the book

This task entailed its own tools and techniques and even, in some cases, specific customs and dress, which at times underlined the nature of the different social strata concerned.

Sargaço harvesting in this geographical area was originally carried out primarily by farmers in the coastal zone who, as part of their farming activities, went to the sea to collect sargaço for their own fields and sometimes also for sale. These peasants lived farther inland. The inland landscape revealed villages with large farmhouses with wide façades, open porches and low roofs, scattered along winding roads, with churches and adjacent cemeteries, and pine trees separating neighbouring parishes. On the shores stood simple shacks for shelter and storage of algae, implements, and boats.

Sargaço harvest began practically in May, when the species known as the “folha-de-maio” (May-leaf) (Laminaria hypeborea, Phaeophyceae) (Fig. 1j) grows. This alga becomes very hard after drying and decomposes only if the year is rainy (Oliveira et al. 1990, Pereira 2016). The months of greater abundance of sargaço are May and September, because of the tides of the equinoxes.

The most convenient period for this activity is undoubtedly summer—June, July, August, and often also September. In June the folha-de-junho or folha-mimosa (June-leaf or mimosa-leaf) begins to grow, consisting of fine algae that are harvested in July. After September, the catch is generally irregular and hardly profitable; from November onwards, it is practically nil. However, there are often bountiful spells after a few days of rough seas, which pull the algae from the submerged peninsula, near or far, and drag them to the coast. Certain days of exceptional abundance live a long time in the memory of the “sargaceiros” (Guimarães 1916).

2.1.1 Composition and characterization of sargaço

Among the various algae that are collectively referred to as “sargaço” (see also section 4), the most frequently found, on the Minho coastline, belong to the group of brown macroalgae (phylum Ochrophyta, class Phaeophyceae), which in Portuguese is named bodelha (Fucus vesiculosus) (Fig. 1g), botelho-bravo (Pelvetia canaliculata) (Fig. 1k), cintas (Saccorhiza polyschides) (Fig. 1m), cordas or corriolas (Himanthaliae longata) (Fig. 1h), folha-de-maio (Laminaria hypeborea) (Fig. 1j), and taborro (algae of the genus Laminaria and Saccorhiza) (Fig. 1m). Among the red algae (phylum Rhodophyta) are found the macroalgae guia or francelha (Gelidium corneum) (Fig. 2b), botelho-crespo (Chondruscrispus) (Fig. 1o), and argancinho-das-lapas (Osmundea pinnatifida) (Fig. 2g) (Pereira 2010a, Pereira and Correia 2015, Pereira 2016). They were all used in agriculture, both as fertilizers and as phytosanitary products (Matos 2018).

The taborro, however, because it has a high water content, is usually separated from the other species and used green immediately after harvesting, without being subjected to the drying and composting process. It is therefore used essentially as meadow fertilizer, or mixed in plowed land, before any seeds are sown.

Red seaweed species, after drying, is used in the pharmaceutical and cosmetic industries and also in the manufacture of agar (E406), carrageenan (E407) and plastics.

Very rich in lime, potassium, phosphoric acid and nitrogen, sargaço is an excellent natural fertilizer. As it dries, the content of those substances rises considerably, and only water decreases by about 60%. Table 1 presents the mineral composition of the fresh and dry sarg...

Table of contents

• Cover
• Title Page
• Copyright Page
• Preface
• Acknowledgements and Credits of Images
• Table of Contents
• 1. Historical Use of Seaweed as an Agricultural Fertilizer in the European Atlantic Area
• 2. Macroalgae Polysaccharides in Plant Defense Responses
• 3. Marine Macroalgae: A Potential Source of Plant Growth Regulators
• 4. Role of Secondary Metabolites from Seaweeds in the Context of Plant Development and Crop Production
• 5. Seaweeds as Plant Biostimulants
• 6. Seaweeds in the Control of Plant Diseases and Insects
• 7. Algae as a Promising Feed Additive for Horses
• 8. Bioactive Algae and Cell Therapies – An Irreversible Perspective in Clinical Nutrition of Horses with Endocrine Disorders
• 9. Seaweeds as Fish Feed Additives
• 10. Effects of Feeding with Seaweeds on Ruminal Fermentation and Methane Production
• Index
• About the Editors
• Color Plate Section