aspeagro.com en brochure biostimulants mol

Technical report

All the research mentioned in this report have been carried out by our R + D + I Department in collaboration with the Department of Agrochemistry and Biochemistry of the University of Alicante.

Index 1. Introducciรณn.

2. Definitions.

3. Composition and structure.

4. Actions of humic substances.

4.1 Indirect effects.

A. Supply of nutrients to the roots.

B. Improvement of soil structure.

C. Increase in the microbial population.

D. Increase in capacity for cathic exchange (CCE).

E. Combination with xenobiotics.

4.2 Effects on the plant (direct effects).

A. Absorption of humic substances.

B. Incidence in germination and plant growth.

C. Growth and root development.

D. Absorption of macronutrients.

E. Absorption of micronutrients.

F. Effects on cell membranes.

G. Energy metabolism.

H. Synthesis of proteins, nucleic acids and enzymatic activity.

5. MOL and organic farming.

6. Directions for use and dosage.

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1. Introduction In recent years, scientists, technicians, professionals and farmers have witnessed a real confusion about the so-called humic substances, organic products of very diverse origin: leonardite, vegetable waste, animals, peat, lignite, etc. The information available on these products is sometimes confusing and not well founded, which can lead to a wrong choice in the product that interests us, the doses to be applied or the most appropriate time for its use, so that the results obtained in many Sometimes they are not the most desired.

With this report, we intend to offer a clearer vision on this type of products so widely used in world agriculture.

We will put special emphasis on the definitions, compositions and effects, so that we can have useful and complete information that allows us to better understand the humic substances.

2. Definitions to describe the dark colored organic material present in the soil. This author observed that the humus was richer in C and poorer in H and O than the plant material of origin.

The soil biomass is the living organic matter included Before delving into the effects and properties of in the microbial tissues, while the humus, would be humic substances, it would be best to define precisely the mixture of complex organic substances of high the terminology we are going to use. molecular weight, colloidal nature and acidic properties; Sometimes, this term is also used as a Organic Soil Matter is one of the most important synonym for organic matter. natural resources, recognized since antiquity as a primary agent in its fertility. It is defined as the Soil organic matter includes a broad spectrum of totality of the organic substances present in the soil, organic constituents, many of which come from including the remains of unaltered vegetable and biological tissues. animal tissues, their products of partial We can distinguish two large groups, non-humic decomposition, the biomass of the soil, the organic substances and humic substances. fraction soluble in water and the humus.

In the 19th century, De Saussure was the first to use the word "humus" (which in Latin means soil) Figure 1.

Different organic fractions in the soil.

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Since the appearance of agriculture, approximately 12,000 years ago (Neolithic) in the lands of the Middle East, the interest in knowing the interaction of organic matter with plants and soil has been maintained throughout history.

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Non-humic substances include those organic compounds that belong to chemically recognizable and non-exclusive species of the soil: • Polysaccharides • Simple carbohydrates • Amino sugars • Proteins • Amino acids • Fatty acids • Waxes • Lignin • Resins • Pigments • Nucleic acids • Hormones • Organic acids Most of these substances are easily degradable, can be used as a substrate by soil microorganisms and have a transitory existence in the soil.

Humic substances can be defined as a category of substances yellow to black

of high molecular weight and refractory properties, they also have colloidal nature and resistance to microbial attack. This statement, however, is more a description of the humic substances than a definition, and is a sample of the non-specificity that prevails in the study of these substances. These materials result from the degradation of remains of animals and plants, and can not be classified within the category of discrete compounds as with non-humic substances.

Humic substances are ubiquitous, and are found in all soils, sediments and waters.

Carbohydrates

We can make an estimate of the composition average of the organic matter of the soil (Figure 2), although we must consider that they are very influenced by environmental conditions.

N Compounds Lipids Humic substances

Figure 2.

Average composition of soil organic matter 5

3. Composition and structure Within these heterogeneous substances, of colloidal nature that we have called humic substances, we find two groups of compounds known as humic acids and fulvic acids that we could define as: • Humic Acids: Dark colored organic material that can be extracted from the soil by alkalis and other reagents and that is insoluble in dilute acid. • Fulvic Acids: Fraction of soil organic matter that is soluble in both alkali and acid.

Although humic and fulvic acids share in large part the effects on soil and plant, their different structure and physico-chemical properties make them more efficient for certain functions (Figure 3).

Therefore, despite being considered globally as humic substances, humic acids and fulvic acids have many differences

FULVIC ACID HUMIC ACID

+ +

Color intensity Degree of polymerization Molecular weight Concentration of C Content of N Similarity to lignite Content in O Acidity and CIC

Figure 3. Properties of humic substances.

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+ +

physical-chemical factors that make the behavior in the soil and its physiological actions in the plants are different according to the fraction used.

Of the variety of functional groups that the humic substances have, the most frequent in the structure of the fulvic and humic acids are usually the -COOH (carboxylic), -OH (phenolic and alcoholic), quinonic and ketonic groups. The concentration in which these functional groups are found in humic substances varies according to their origins. The total acidity, and therefore the groups that contribute most to it (-COOH and -OH), is higher in fulvic acids than in humic ones. In contrast, humic acids have a higher percentage in quinonic groups.

As we have already mentioned, knowledge of the basic structures of humic and fulvic acids is necessary to understand the role and function of these constituents in plant nutrition, however the multiple molecular components of which they are formed means that we can not

establish structural formulas in a definitive way, although with the development of the latest analytical techniques (Nuclear Magnetic Resonance, NMR, Electronic Spin Resonance, ESR, etc.) along with advances in computer science have been able to establish three-dimensional structural models (Figure 4).

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% w/w

Figure 4.

Three-dimensional structure for a humic acid.

The MOL product range is made up of the MOL, MOL Org, MOL Solid and MOL Solid Combi products, whose open-ended composition is attached

Organic material Total humic extract Humic acids Fulvic acids Organic Nitrogen Potassium (K2O)

42,5 18,1 11,0 7,1 4,5 3,5 1,02 1,27

% w/w

Total Organic Matter Humic acids Fulvic Acids Potassium (K2O)

80,0 65,0 15,0 7,0

pH 10%

7

7

4. Actions of humic substances In the middle of the 19th century, Justus von Liebig established that the principle of plant nutrition was determined by chemical elements called nutrients (carbon, oxygen, nitrogen, potassium, etc.) that plants take in various Justus von Liebig forms: CO2, NO3 -, K +, Mg2 +, and once absorbed via radicular or aerial constitute the materials, the fundamental bricks from which the plant building is built. Therefore, humus is not essential "per se" for plants, but it does play an important role in controlling a number of factors of nutrition, both in the soil and if we grow in hydroponic conditions.

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What are, therefore, the effects derived from the humic substances, what make them practically indispensable in the current agriculture? These effects have been explained by different theories, however, the most accepted by the scientific community is the hypothesis that assigns direct effects to humic

substances on the plant, having an almost hormonal behavior, and indirect effects acting on the metabolism of soil microorganisms and the dynamics of nutrients in it.

When addressing the effects of humic substances, the following factors should also be taken into account: • The properties of the soil.

• The concentration in which humic substances are found.

• The nature of these compounds.

• The molecular weight of the humic fractions.

• The content in functional groups.

• The plant species, its age and phenological status.

4.1 Indirect effects Humic substances can indirectly affect plant nutrition through different mechanisms.

A. SUPPLY OF NUTRIENTS TO ROOTS. The humic substances can serve as a source of N, P and S, which release through the mineralization that organic matter suffers in the soil. This source of elements that have humic substances is also due to the possibility of complex metals.

The dynamics of P in the soil depends on the Ca complexation by humic matter. In limestone soils, Ca is a reactive cation and ubiquitous that decreases bioavailability of numerous micronutrients (Fe2 +, Zn2 +, Cu2 +), as well as P, due to the formation of insoluble calcium phosphates. The complexation of Ca for humic substances increases the solubilization of apatite limiting adsorption and fixation of P. The results show that the Ca complexing power of substances humic is well related to the improvement in

The nutrition of P in limy soils, in addition, the positive effect of the complexation of Ca on P seems to depend on the pH of the soil. Tests with MOL and MOL SOLID showed that increasing the pH of the medium increased the concentration of calcium complexed. (Figure 5)

PEAT

MOL Solid

AH-COMPOST

MOL

The application of MOL and MOL SOLID in tomato plants showed a significant increase in the iron content of radicle (Figure 6), also improving nutrition with respect to other elements such as N, Ca or P. An explanation for the increase in the concentration of iron could be due to the formation of soluble complexes of Fe3 + that increases the amount of iron available and its transport to the root.

MOL

MOL Solid

SH Doses (mg/L) Figure 5. Power of Ca2 + complexation of humic substances vs pH.

Figure 6. Root content of iron (mg / kg m.s.) compared to the application of MOL and MOL SOLID 9

C. INCREASE IN THE MICROBIAL POPULATION. The addition to the soil of humic substances, which can be used as a carbon source, increases the microbial population (Figure 7) and therefore the associated enzymatic activity.

The fulvic acids present in MOL, and more specifically their quinonic groups, seem to favor the reduction of Fe (III) by iron-reducing bacteria.

107 Cells/g

MOL g/100 g Soil

Figure 7. Increase in total bacterial population in soils with the amount of MOL applied to the soil, 30 days after application.

In the fertility of the soil, the exchange of cations of the organic fraction is of absolute importance, since it will suppose the supply of K +, Ca2 +, Mg2 + and some micronutrients (Fe3 +, Cu2 +, Mn2 +, Zn2 +) for the plants. The Cationic Exchange Capacity of the soil can depend on more than 80% of the organic matter, therefore there is a direct relationship between CEC and the organic matter content (Figure 8). In general, humic acids will adsorb preferentially polyvalent cations (Ca2 +, Mg2 +, Fe3 +, Zn2 +, Cu2 +) against monovalent ones (K +, Na +, NH4 +).

E. COMBINATION WITH XENOBIOTICS.

Soil CEC cmol/Kg

A developed and stable structure is of great importance in soils to have good aeration and water retention capacity. This property is very determined by the ability of organic matter to join soil particles together and act as a cement of them, which gives the root a more suitable environment and contributes to a better growth of the plant.

D. INCREASE IN CATIÓNIC EXCHANGE CAPACITY (CEC).

Organic Matter

The humic substances will affect the ioactivity, persistence and biodegradability of pesticides. The combined effects of humic substances and herbicides can produce synergistic or antagonistic responses of the plant depending on the origin and nature of the material.

Figure 8. Relationship between the organic matter of soil and its CEC. 10

We must not forget that for solid organic matter to produce these effects on the soil, the contribution of large quantities is often necessary.

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B. IMPROVEMENT OF THE SOIL STRUCTURE.

In recent years, research on humic substances has been focused on their direct actions. Their biostimulant effects have been investigated considering the implication of these products in the different physiological-biochemical processes that take place in the plant.

The direct effects require small quantities and more precise molecular sizes and structures, the effects on the plant can be done either by the compounds or organic structures present in the soils or by foliar application of humic substances.

they arrive at the following conclusion: while the fractions of low molecular weight, like the fulvic acids, are taken by the roots and translocated to the interior of the plant actively and passively, the humic acids only do it passively, therefore we could consider that fulvic acids are more physiologically active than humic acids, however we must not forget that humic acids often contain fractions of low molecular weight, and therefore we should not underestimate their potential as a biological activator.

A. ABSORPTION OF HUMIC SUBSTANCES.

B. INCIDENCE IN GERMINATION AND VEGETABLE GROWTH.

To consider the direct effects of humic substances on plant growth, we must consider that these substances can be absorbed by the plant species. Since the mid-twentieth century, various analytical methods have been proposed that would allow concluding that humic and fulvic acids were incorporated into plant material. The latest research on this subject

One of the effects generally assumed by humic substances is their influence on the germination of the seeds. Our research has shown how MOL and MOL Solid improve the percentage of germination of tomato seeds, even in saline conditions (Figure 9).

This increase in germination produced by the action of MOL and MOL Solid has been justified in considering that these materials influenced the enzymatic activity of the seeds and / or cellular respiration processes.

% Germination with respect to control

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4.2 Effects on the plant (Direct effects)

CONTROL

MOL

MOL Solid

Figure 9. Percentage of seed germination tomato cv Daniela regarding the control.

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C. GROWTH AND RADICULAR DEVELOPMENT. If we refer to the influence of humic substances on the growth and development of the root, we have verified that the application both to the soil, and foliarly of MOL and MOL Solid improve the root growth, influencing the elongation and the formation of the first ones root hairs. The application of MOL in lettuce seedlings significantly improved root growth, going from an average root length of 13.6 mm for the control to 20.2 mm.

The latest research considers that humic substances contain compounds that serve the vegetable as precursors or substrates for the synthesis of hormone-like substances, which would explain the effect that humic substances have on the radicular and functional development of plants.

Root development with and without application of MOL (tomato).

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Without MOL

With MOL

have shown how the application of MOL and MOL SOLID diminishes the serious effects of salinity, The stimulation of plant growth produced by humic reflected in a decrease in foliar sodium in crops substances has been generally related to the such as table grapes, tomatoes or peppers. improvement in the macronutrient content. In our (Figure 10) trials we have observed that the application of MOL and MOL Solid in tomato plants produced improvements in P and K concentrations.

MOL Solid

MOL

PEPPER

% Na in m.s.

A special case is the Na. Although considered as Figure 10. Influence of humic substances on the Na content macronutrient, in some areas such as the in the pepper and tomato culture.

Mediterranean, the levels reached end up turning it into a danger for the proper development of plants. LThe salinity problems that the soils and waters of the Spanish Southeast usually present (Valencia, Alicante, Murcia and Almería) are closely related to the presence of Na +, this element causes osmotic imbalances in the interior of the plant, disturbances in the water balance and toxic effects such as the decrease in the metabolic energetic rate, which entails serious decreases in the productive yields. The results of our investigations PEAT TOMATO

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D. ABSORPTION OF MACRONUTRIENTS.

Treatment 13

LEMON

The importance of humic substances lies also in their ability to form complexes with the different transition metals.

In limy soils, with alkaline pH, the concentration of micronutrients in the soil solution may be insufficient for the needs of the plants. In this case, the stimulation of plant growth, by the application of humic substances, can be attributed above all to the maintenance of Cu, Zn, Mn and especially Fe in solution, at levels that avoid the appearance of micro-deficiencies.

In our research we have evaluated the ability of humic substances to mitigate the effects of iron deficiency in tomato plants; the results have shown that the application of MOL and MOL SOLID in conditions of iron deficiency, avoided the appearance of the symptoms of iron deficiency, such as internervial yellowing of young leaves and less vegetative development.

(Figure 11)

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Copper

Manganese

Zinc

Manganese

Zinc

Manganese

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E. UPTAKE OF MICRONUTRIENTS.

MOL Solid MOL TABLE GRAPE

MOL Solid MOL TOMATO

MOL Solid MOL The letters a and b indicate statistical differences Probability levels:

Normal Values

Copper

Manganese

Zinc

LEMON TABLE GRAPE TOMATO

Field trials conducted with MOL and MOL SOLID in fertigation have shown better foliar levels of Cu, Mn and Zn in tomato, citrus and table grape plants.

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Uno de los mecanismos que utilizan las plantas dicotiledóneas para combatir la clorosis férrica es la liberación radicular de protones y aumentar la actividad de la enzima Fe(III)-reductasa en la superficie de las células radiculares. Ensayos en cámaras de cultivo controlado sobre plantas de tomate, mostraron que la aplicación de MOL y MOL Solid producía un aumento en la capacidad de reducción de Fe(III), evitando la aparición de la deficiencia en estas plantas.

(Figure 12)

Uno de los mecanismos que justifican la mejora en los niveles de Fe en la planta al aplicar sustancias húmicas, ha sido la posibilidad que tienen estos compuestos de catalizar la reducción de Fe(III) a Fe(II). Esta reducción iónica es de considerable importancia ya que va a modificar las características de solubilidad de estos iones metálicos y mejorar su disponibilidad para las plantas y microorganismos.

D Fe MOL

Figure 11. Síntomas de deficiencia de hiero desarrollados por plantas de tomate y recuperación por la aplicación de MOL y MOL Solid.

D Fe MOL Solid

Figure 12. Aumento de la actividad de la enzima Fe(III)-reductasa al aplicar MOL y MOL Solid en plantas de tomate deficientes en hierro.

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La estimulación en la toma de nutrientes debido al tratamiento con materiales húmicos, ha llevado a muchos investigadores a proponer que estas sustancias afectan a la permeabilidad de las membranas. La manera en la que actúan las sustancias húmicas sobre las membranas no está del todo clara, aunque es probable relacionarla con la actividad superficial de los compuestos húmicos como consecuencia de sus propiedades hidrófobas e hidrofílicas. De este modo, las sustancias húmicas pueden interactuar con las estructuras fosfolipídicas de las membranas celulares y comportarse como transportadores a través de ellas.

Algunos autores afirman que las sustancias húmicas en la rizosfera podrían ser afectadas por los ácidos orgánicos procedentes de los exudados de las raíces o del metabolismo microbiano, y por tanto ser disociados en constituyentes de menor peso molecular dotados con actividad hormonal.

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Nuestros ensayos muestran que la aplicación de MOL y MOL Solid aumentaba la permeabilidad de membrana en plantas de tomate, esta determinación se realizó a partir de la pérdida de electrolito, medida mediante cambios en la conductividad eléctrica. (Figure 13)

G. METABOLISMO ENERGÉTICO. Diversos trabajos demuestran que la presencia de sustancias húmicas mejora la fotosíntesis y la respiración (Figure 14 y Figure 15). Las plantas de tomate crecidas en aquellas disoluciones nutritivas que contenían MOL MOL y MOL SÓLIDO producían mayores niveles de clorofilas; de la misma forma también aumentó el consumo de oxígeno comparado con el control. De esta forma, se demostraba que los ácidos húmicos y fúlvicos tenían un efecto directo en la respiración. Los resultados sobre los niveles de clorofila a, clorofila b y clorofila total en plantas de tomate mostraron un aumento con la incorporación de MOL y MOL SÓLIDO a los tratamientos. (Figure 15) H. SÍNTESIS DE PROTEÍNAS, ÁCIDOS NUCLÉICOS Y ACTIVIDAD ENZIMÁTICA.

CONTROL

MOL

MOL Solid

Figure 13. Incremento en la permeabilidad de membrana al incorporar MOL y MOL Solido en la disolución nutritiva de plantas de tomate.

Las sustancias húmicas influyen en la síntesis de ARN-m, el cual es esencial para los principales procesos bioquímicos que ocurren en la célula.

Numerosos trabajos recogen la influencia

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F. EFECTOS SOBRE LAS MEMBRANAS CELULARES.

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de las sustancias húmicas en la síntesis de proteínas, especialmente enzimas. Diversos trabajos han mostrado que las sustancias húmicas influyen en el desarrollo de enzimas como catalasa, o-difenoloxidasa y citocromo en tomates o invertasa y peroxidasa en remolacha. Diversos autores denominan a la acción hormonal de las sustancias húmicas como comportamiento “auxin-like”. Resulta muy difícil explicar los mecanismos por los que las sustancias húmicas afectan a las actividades de las enzimas. Los diferentes mecanismos están relacionados con la reactividad de los grupos funcionales de los materiales húmicos, que varían dependiendo de la enzima en cuestión.

Figure 15. Efecto del MOL y MOL SÓLIDO en los contenidos de clorofilas en hojas de tomate

Figure 14. Efecto de MOL y MOL SÓLIDO en la respiración y en los niveles de clorofila en plantas de tomate.

CONTROL

MOL

MOL Solid

Control MOL MOL Solid 17

5. Modo de empleo y dosis

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CULTIVO CÍTRICOS ÁRBOLES FRUTALES FRESA FLORICULTURA HORTICULTURA ABIERTA INVERNADERO MAÍZ OLIVO PERAL UVA DE VINO UVA DE MESA CULTIVO RAYGRASS ORNAMENTAL HORTICULTURA

APLICACIÓN AL SUELO ÉPOCA Medio ciclo de primavera Medio ciclo de primavera Ciclo completo Ciclo completo Ciclo completo Ciclo completo Durante el primer riego Ciclo completo Medio ciclo de primavera Medio ciclo de primavera Medio ciclo de primavera APLICACIÓN FOLIAR Dosis general: 1-3 L MOL/200L NÚMERO DE APLICACIONES 5-6 aplicaciones 5-6 aplicaciones 3-4 aplicaciones

DOSIS ANUAL 100-140 cc/árbol 100-160 cc/árbol 120 L/Ha 100-120 L/Ha 80-120 L/Ha 100-120 L/Ha 50-80 L/Ha 110-120 cc/árbol 30-50 L/Ha 30-60 L/Ha 70-100 L/Ha DOSIS ANUAL 5 L /1000 m2 100 cc / 20 L 1-2 L/200 L

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1. Enriquecimiento de substratos Mezclar 10 a 20 g. de MOL COMBI SOLID por m3 de substrato.

2. Fresas Foliar: 30-60g/100L; 2 a 6 tratamientos (dosis total por cultivo: 100-200 g/1000 m2). No pulverizar en floración.

Suelo: 50-100 g/1000 m2 y aplicación, repetir el tratamiento cada 3-5 semanas (dosis total por cultivo: 300-500 g/1000 m2).

3. Hortalizas Foliar: 20-50 g/L; 2 a 4 tratamientos (dosis total por cultivo: 100-200 g/1000 m2). En rábanos, no superar concentraciones de 10 g/100L).

Suelo: 50-100 g/1000 m2 y aplicación, repetir el tratamiento cada 2-4 semanas (dosis total por cultivo: 200-600 g/1000 m2).Las dosis mayores se utilizarán en cultivos de alta producción (tomate y pepino en invernadero, etc.).

4. Viveros Planteles: aplicaciones en pulverizaciones a una concentración 20-40g/100L. Contenedores: preparar una solución al 0,05% (0,5 g/L) y aplicar a razón de 200 g. por litro de substrato.

Plantas vivaces: regar con una solución al 0,1% (1g/L) a razón de 100-150g/100m2.

5. Frutales Foliar: 50-150g/100L; 2 a 6 tratamientos (dosis total por año: 3-8 Kg/Ha. Suelo: 0,5-1,5 Kg/Ha y aplicación, repetir el tratamiento cada 2-5 semanas (dosis total por año: 4-7 Kg/Ha).

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¿CÓMO APLICAR MOL Solid?

Recomendamos aplicar MOL Solid como una disolución. Pesar la cantidad de MOL Solid (1 parte) y disolver en 10 partes de agua; añadir esta disolución al sistema de riego (al tanque de agua, etc.).

MOL Solid es totalmente soluble en agua, la disolución al 10% de MOL Solid es miscible con la mayoría de fertilizantes y pesticidas solubles en agua y que son usados comúnmente. No obstante, recomendamos una pequeña prueba de compatibilidad antes de usar MOL Solid la primera vez.

MOL y MOL Solid son productos compatibles con la mayoría de productos fitosanitarios y abonos foliares. No obstante, no se debe mezclar con productos que especificamente no admitan su mezcla con productos orgánicos

Con la ilusión del neófito y la constancia derivada de la experiencia nos presentamos ante usted, estimado cliente, en el inicio de una nueva etapa de nuestra vida empresarial.

Una vez más Agrícola de Aspe quiere ofrecerle lo mejor de nosotros, y como pequeña muestra de ello, hoy llevamos a sus manos una nueva “memoria técnica” de uno de nuestros productos más veteranos y prestigiados en mercados nacionales e internacionales: MOL (Ácidos Húmicos).

Este documento, que hoy presentamos, pretende actualizar nuestros conocimientos en relación a este producto, así como iniciar la publicación de una serie de memorias divulgativas de productos tales como: STYM 25 (Aminoácidos), COLOR K (fertilizante potásico altamente asimilable).

Con el ánimo renovado y la mejor disposición, queremos agradecer a todos nuestros clientes su confianza durante todos estos años y expresar nuestra disposición a seguir sirviendo, con la misma ilusión y entrega.

Nos reafirmamos en nuestro compromiso cotidiano para poder seguir contando con su confianza y apoyo. Decía un célebre autor que “Cuando no falta voluntad siempre hay un camino”.

Muchas gracias.

Dr. Juan J. Sánchez Andreu