What are Organic Fertilizers used for?

Updated: Sep 8, 2020

Today there are several well-founded reasons to use Organic or Ecological methods.

In today's conventional agriculture, Farmer's depend on Agrochemicals and industrialized technologies to produce their crops. which require high investment of money and eventually lead to pollution and environmental degradation and thus hinders the economic development of the agriculture sector and of rural areas; an unsustainable situation in the long term.

In underdeveloped countries, where labor and land are the most available factors of production, organic farming represents an important alternative for the development and advancement of the field, as well as the main way to achieve healthier products.

In this article we will take a closer look at organic fertilizers, and we will discuss their different types and benefits.


Organic fertilizers are substances that are made up of waste of animal or vegetable origin that are added to the soil in order to improve its physical, biological and chemical characteristics. These may consist of crop residues left in the field after harvest; green manures (mainly nitrogen fixing legumes); organic remains from the farm (manure, slurry); organic remains from the processing of agricultural products; household waste, (household waste, excreta) and compost prepared with the mixtures of the aforementioned compounds.

This class of fertilizers not only provides nutritious materials to the soil, but also favorably enhance the structure of the soil. Likewise, they provide nutrients and modify the population of microorganisms in general, thus ensuring the formation of aggregates that allow greater water retention, gas and nutrient exchange, at the plant root level.

What are the Benefits of Using Organic Fertilizers?

Cultivated lands suffer the loss of a large amount of nutrients, which can deplete the organic matter of the soil, for this reason they must be constantly renewed. This can be achieved through the management of crop residues, the use of organic fertilizers, manure or other type of organic material introduced into the field.

Composting consists of applying mineral or organic substances to the soil in order to improve its nutritional capacity. Through this practice, the nutritive elements extracted by the crops are distributed in the field, in order to maintain a renewal of nutrients in the soil. . The use of organic fertilizers is especially recommended in soils with low organic matter content and degraded by the effect of erosion, but their application can improve the quality of crop production in any type of soil.

The composition and nutrient content of manure varies greatly according to the species of animal, the type of management and the state of decomposition of the manure. Chicken manure is the most nitrogen-rich manure, on average containing twice the nutritional value of beef manure.



Manure is the excrement of animals that results from the digestion process of the food they eat. Generally between 60 and 80% of what the animal consumes is eliminated as manure.

The estimation of the quantity produced by an animal can be done in the following way:

Average animal weight x 20 = amount of manure / animal / year.

The quality of the manure depends on the species, the type of bed and the handling given to the manure before it is applied.

Manures improve the biological, physical and chemical properties of soils, particularly when they are used in a diversified way.

To obtain greater advantages, they should be applied after being fermented, and preferably with an adequate soil moisture.

Islands guano (bird droppings)

It is a mixture of sea bird droppings, feathers, remains of dead birds, eggs, etc., which undergo a slow fermentation process. The use of island guano has been known in Latin America for more than 1500 years.

It is one of the best quality natural fertilizers in the world, due to its high content of nutrients, and can have 12% Nitrogen, 11% Phosphorus and 2% Potassium. It is mainly used in sugarcane, potato and vegetable crops. .

It must be sprayed at an acceptable depth, or covered immediately, to avoid loss of ammonia. It can be mixed with other organic fertilizers to increase its mineralization and achieve better efficiency.

Earthworm Humus

Earthworm humus is the name given to the excrement of earthworms dedicated especially to transforming organic waste and also those produced by earthworms as their digestion waste.

The California Red Earthworm (Eisenia foetida) has adapted very well to our conditions and is very widespread in the different regions of the country.

Earthworm humus is also the organic fertilizer with the highest bacteria content, it has 2 billion bacteria per gram of humus; for this reason its use is effective in improving the biological properties of the soil.

Green Manure

Green Manure in most cases is the best technique to associate with phosphatisation in the correction and initial fertilization of the soil.

Green manuring is a practice that consists in growing plants, especially legumes (clover, alfalfa, beans, alfalfilla, kudzu, mucuna, crotalaria, desmodium, etc.) or grasses (such as oats, barley, ray grass, etc.), and then incorporate them into the soil while they are still green, without previous decomposition, with the purpose of improving the physical, chemical and biological conditions of the soil, restoring and improving its natural fertility. It is advisable to use mixtures of crops to use, such as green manures, because while legumes provide nitrogen, grasses improve the content of organic matter.

Green Manure Concept: Any competitive plant that is well adapted to a certain location, that produces a large amount of biomass and collaborates with the structure. They generally constitute good fodder and agricultural products.


It is a natural fertilizer that results from the transformation of the mixture of organic residues of animal and vegetable origin, which have been decomposed under controlled conditions. This compost is also known as "topsoil" or "mulch". Its quality depends on the inputs that have been used (type of manure and plant residues), but on average it has 1.04% N, 0.8% P and 1.5% K. It may have contaminating elements if it has been used urban garbage. When using stabled manure from cattle (milk or fattening) there are risks of salt problems. In these cases, a reduced amount of manure and plenty of straw should be used. It is highly appreciated in nurseries, to make various types of mixtures with sand and cape soil that are used to make seedlings of vegetables, flowers, shrubs or trees.

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