ما هو الدبال ومما يتكون وما خصائصه وفوائده وطرق زيادته في التربة

What is humus? Many people who are interested in studying soil and its types want to know what humus is and how it is formed, and how it contributes to improving soil properties and increasing its fertility, as humus contains a high percentage of nutrients and biological materials that enter into activating physiological processes. For plants, the concentration of humic substances in the soil varies, and their concentration can be increased by adding many substances and fertilizers to the soil.

What is the definition of soil?

Soil is defined as a biologically active porous environment because it was formed in the upper layer of the earth’s crust. Soil is one of the main layers of life on the earth’s surface because it serves as a reservoir for water and nutrients, as well as a means to filter and destroy hazardous waste, and is also involved in the processing of carbon and other elements in the global ecosystem and processes Weathering that is controlled by biological, climatic, geological and topographical influences is one of the most important factors influencing soil formation.[1]

What is humus

Humus is a group of plant and animal residues that are analyzed by a group of bacterial organisms that live in them and transformed into new materials after analysis. And hormones, in addition to cellulose, pectin, resins and gums, and the decomposers in the middle of this mass of materials are affected by temperature, humidity, ventilation and climatic conditions, and some elements are returned to the air directly, for example carbon dioxide, carbon dioxide and nitrogen in the form of ammonia NH3 or free nitrogen, Or in the form of ammonia salts, which eventually form other substances needed by plants and stored in the soil, and in general the humus in the soil contains 45% lignin compounds, 35% proteins, 11% carbohydrates, 3% fats and wax, and 6% substances Other organic humic substances are unstable, and their quantity in the soil is constantly increasing due to new additions, as their substances are decreasing due to constant dissolution.[1][2]

What is the main source of humus in soil?

How is humus formed?

Humus is formed over time as a result of the bacterial decomposition of plants and animals. It contains 60% carbon, 6% nitrogen, and less than phosphorous and sulfur. Usually, when humus decomposes, its components turn into shapes. Humus consists of three main types, which differ from each other according to the types of organic matter. of which it consists, and the plants to which it belongs, and these divisions are as follows:[3][4]

Moore humus (acid): It is a type that is formed in the soil that contains many organisms, the most famous of which are fungi and small arthropods. It is widespread in coniferous forests and cold areas.
Mull humus (alkaline): It is a type of humus that forms in deciduous forests or grasslands in areas with warm and humid climates. The humus with large pores is characterized by rapid decomposition and mixing with soil rich in minerals, so the soil layers are not clear, and there is a good percentage of living organisms in it, and it is alkaline soil; Any high pH.
Humus Mudder (Neutral): It is a humus that is medium between mol and moar humus in terms of pH. This type of humus consists of more organic substances than humus of the alkaline type, but the material does not mix well with mineral components.

What is the importance of humus?

Humus contains many nutrients useful for healthy soil, and the most important of these elements is nitrogen, which is the main nutrient for most plants. Therefore, agriculture in many areas depends on the presence of nitrogen in humus and other humus components. Some experts believe that humus makes the soil more fertile. Research confirms that humus helps prevent plant and crop diseases, and humus can be obtained naturally or produced through a process called composting, which decomposes organic matter such as food and agricultural waste to turn it into soil.[5]

Water that is above the surface of the earth and does not require effort to extract it is called water

Characteristics of living organisms in humus

Soil mainly contains a large number of living organisms; Whether they are animals or plants, the group of microbes includes: bacteria, fungi, algae, protozoa and viruses, as well as worms and land insects, and the density of each of these organisms in the soil depends on the conditions prevailing in it. When we address the importance of bacteria and fungi in humus and soil, we find the following data:[6]

bacteria

The simplest soil organisms number approximately 100 million cells/gram in soil, and one acre of good quality soil contains 250-150 kg/g of bacteria; Depending on the depth of the arable layer, and the amount varies according to soil conditions such as temperature, humidity, acidity and depth. Bacteria live in colonies in soil granules that are spherical or spiral in shape. One of the most important biological processes carried out by bacteria in soil is the fixation of nitrogen in the atmosphere; That is, the conversion of atmospheric nitrogen into a form that benefits plants through symbiotic and non-symbiotic fixation.

fungi

They exist in the form of intertwined cells and make up 50-30% of soil microbes, and they spread in forests and acidic soils and their role in soil is to help break down organic matter, and can form a symbiotic relationship with plants, some of which cause disease.

What are the components of humus?

Humus in the soil contains approximately 45% of lignin compounds, 11% of carbohydrates, 35% of protein substances, 3% of fats and waxes, 6% of other organic matter, and the proportion of nitrogen and carbon in it is 10-14: 1, and usually it does not exist in a static equilibrium, rather it is found in a moving equilibrium when its quantity in the soil is constantly increasing due to the entry of new organic matter into the soil, and on the other hand, the humus in the soil also decreases due to its continuous dissolution, the composition of humus also changes in its composition from one soil to another ; Depending on the environmental and weather conditions, because its composition depends on several factors such as, humidity, temperature, ventilation, plant type, growth method and other factors, and any difference in these factors leads to a change in the composition of humus, and thus a change in the ratio of carbon to nitrogen, and varies The formation of humus is also in different layers of the same soil, where the humus is found in the soil with the highest percentage on the surface, and then its percentage gradually decreases with the depth of the soil.[6]

The part of the plant that bears the leaves and flowers

The benefits of humus for the soil

Humus is a colloidal brown compound rich in energy, provides the plant with the elements necessary for life and has a high water-holding capacity. Its presence in the soil, even in small quantities, increases soil fertility and productivity. It is a permanent component of the organic part of the soil and plays a multifaceted role in it, including:[5][6]

Humic substances in their nucleus and side chains contain a group of elements such as calcium, potassium, sulfur and phosphorous, which are of great importance to plants, as during their decomposition these elements are released and become ready and easy for plants, and on this basis humus is a reserve source of food and helps the soil to retain water.
Humus water contains dissolved salts necessary for plant growth.
Humus improves soil properties due to its colloidal properties and ability to collect soil granules. It is also a suitable and fertile environment for microorganisms that form viscous materials that bind soil granules.
Humic substances are characterized by high absorption of positive ions and do not allow water to wash them away; Therefore, humic acids that contain oxides of calcium, manganese, aluminum and iron are stable compounds, and in general we find that soils rich in humus have a higher fertility energy compared to soils poor in them.
Aggregation of soil particles and mixing of soil mineral components with organic components in a way that is difficult to separate, except for a change in acidic or basic conditions.
It is a storehouse of nutrients and elements necessary for plant growth, which are released gradually.
Contains growth stimulants such as auxin.
It promotes the growth of some antimicrobial agents and the emergence and growth of fungi, bacteria and some worms harmful to plants.
Humus contains in its main components several important elements such as phosphorous, sulfur and potassium, which play a major role in plant growth.
It increases water retention in the soil, protects the soil from drying out and makes it suitable for plant growth.
Its properties help to collect soil particles and make it a fertile environment suitable for the growth of microorganisms that produce mucus that causes soil particles to stick together.
It is distinguished by its dark color, which gives the soil its distinctive color and increases its ability to absorb sunlight.
It has a high ability to absorb positive ions, while calcium, manganese and aluminum with humic acid are stable chemical compounds that increase soil fertility.

Ways to increase the level of humus in the soil

Many farmers and gardeners want to improve the properties of the soil by increasing the proportion of the soil in its components in inexpensive and effective ways, and this can be achieved by implementing one of the following four methods:[7]

Provide special precautions and conditions.
Putting humus in the soil as a fertilizer.
Providing suitable conditions for the work of worms and living organisms.
The need for regular crop rotation in the garden or vegetable garden.

The proportion of humus in the soil

Soil can be classified according to its fertility, which depends on its ratio for its many benefits on the soil, and the soil is divided into the following types:[8]

Poor soil contains 1% humus.
Humus is moderate and contains about 2% humus.
The average humus is 3% humus.
Black soil contains approximately 15%.

How do flowering plants reproduce?

Agricultural properties of humus

Among the most prominent agricultural properties of humus are the following:[8]

Such quality as friability allows moisture to be well absorbed and retained in the soil for a long time, and air retention is necessary for the roots.
On sandy soils, after applying humus, moisture is retained for a longer time, and it also makes heavy soils more compact and nutritious.
Improves Soil Structure – Capillaries do not form in normal weather, and grow easily in hot weather.
When fertilizing with mineral fertilizers, it contributes to its delivery to plants.
Nutrients allow in the process of humus formation, by not feeding plants during the days of the season; Except when a particular substance is needed to feed the plants.
In turn, it improves the gas nutrition of plants, due to the fact that it contains a large amount of carbon dioxide.
It attracts earthworms.

Humus preparation method

The method of preparing humus includes:[7]

Tools

Humus making tools include:

Large box made of wood.
One removable wooden board for the convenience of drilling.
Holes at the bottom for moisture drainage.
Top – a piece of slate, cellophane, ruberoid.

How to prepare

The method of preparing humus is carried out according to the following steps:[7]

Ready humus is placed under the box in sawdust.
The box is placed in a dark place.
It is better to chop the grass (you can hoe).
Gradually fill the box and mix the contents periodically.
Sprinkle the lawn with soil or sawdust.

What are the layers of soil?

And what does the soil consist of? Soil is divided into three layers, each of which differs in its physical, chemical and biological properties from the layer above and below. Soil consists of three layers:[7]

superficial layer

This layer is also called the humus layer, and this layer consists of decomposing materials and organic materials because it is rich in organic matter and this is the reason for its dark brown color, as the seeds and roots of plants grow in this layer, and many living organisms were found in it, such as earthworms, millipedes and worms millipedes, bacteria and fungi in this soil layer.

subsoil layer

It is located below the surface of the soil, and is characterized by a lighter color than the soil of the surface layer, due to the lack of humus in it, and it also contains a lower percentage of organic matter, but it is rich in minerals falling from the surface soil, and it also contains a low percentage of organic matter, and it contains a large percentage of mineral salts, especially iron oxide, and farmers often mix horizon A and horizon B when plowing their fields for better results.

mother class

This layer is located below the layer directly under the soil, and this layer does not contain organic materials like the other layers, because it consists of rocks and rocks, so it is very solid, and this layer is a transitional zone between each of the two previous layers.

Nonvascular plants usually grow near the surface of the earth because they do not have them

What are the most famous organisms that live in the soil?

There are many things in soil such as organic matter, animals, vertebrates or invertebrates, and there is a known relationship that exists between the animals that live in the soil and plants; Animals depend on these dead plants for energy, and plants depend on animals to rot so that the life cycle continues, making the soil useful in this cycle, fertilizing it with minerals and nutrients from dead and decaying plants and animals, and in general the animals that live in the soil are small in size and simple elongations, and ranges from Their body length ranges from 0.00008 inches to over eight inches, and there are three subcategories in this length range, namely:[8][9]

Microfauna: Length ranges from 0.0002 to 0.002 cm, including protozoa.
Medium animals: from 0.002 to 1.016 cm in length, include butterflies, spiders, insect larvae, isopods, small centipedes, jumping tails, and more.
Large Animals: They are at least 1.016 cm in length and include animals such as earthworms, largest spiders, insects, soil-dwelling vertebrates, and more.

Soil is also home to animals such as burrowing and burrowing animals, as well as animals that use the space between soil particles to move; Since burrowing animals are often found in desert areas where surface temperatures are much higher than soil temperature, some of these desert burrowing animals also include reptiles such as lizards, small mammals such as foxes, and arthropods such as termites.

It stores water, food, salt and waste

Finally, in this article, we explained what is humus and what is the composition of humus, as we indicated its importance in soil fertility, ways to increase its level in the soil, and classification of soil according to the percentage of its presence in it.