Not everyone knows this but there are different types of art agrikola, each with its own characteristics. For every farmer, whether he works professionally or in the home, it is essential to understand what type of land he is dealing with. Each plant, in fact, adapts and grows better on a certain type of soil rather than on another. We too at Organic Cultivation, when we describe a crop, always specify which type of soil is ideal for healthy and luxuriant growth.
Today we will give some definitions that will allow us to understand what are the characteristics and peculiarities of our land. In this way we will identify the right agronomic choices, in terms of processing, fertilizzazzjoni, irrigazzjoni and choice of suitable cultivars.
Soil and agricultural land
According to a well-known and simple definition, the soil is the superficial part of the earth’s crust capable of hosting plant life. Agricultural land, on the other hand, is that part of soil which, due to its characteristics, is best suited to be used by man for agriculture. The latter, therefore, is different from natural soil, also due to repeated processing and various agronomic interventions. Furthermore, agricultural land cannot be seen as an inert entity, but rather as a dynamic system in continuous evolution. On this ground, human interventions should therefore be conservative and ameliorative.
The different types of agricultural land
Thompson diagram for evaluating agricultural land
To classify the different types of agricultural land, the first characteristic to be studied is the insiġ. This study reveals, in fact, the different percentages of mineral particles of which the soil itself is made up. The percentage of solid particles is distinguished by particle size classes, that is, by size. Texture allows us to understand the physical-mechanical properties of agricultural soil.
The main constituent elements of agricultural land are:
- Iskeletru
- Sand
- Clay
- Ħamrija
- humus
Sand, silt and clay make up the so-called “fine earth”. Depending on the different percentages of these elements, the different types of agricultural land can be classified into various textural classes. To do this, just follow the Thompson diagram (pictured).
Let’s see what these elements are in detail.
Iskeletru
The term “skeleton” refers to the largest particles of the soil, ie those greater than 2 mm in diameter. Let’s talk about common elements such as: stones, gravel, gravel, pebbles.
These large particles are the least suitable for cultivation, as they do not retain water and make it difficult to carry out various cultivation operations.
Sand
The sand is represented by elements smaller than those of the skeleton, but still relatively large.
There are different types of sand, which are distinguished according to the size of the granules. In general these have a size between 50 microns and 2 mm.
A further distinction is that in the following sand subclasses:
- Very fine, between 50 and 100 microns
- Fine, between 100 and 250 microns
- Medium, between 250 and 500 microns
- Coarse, between 500 microns and 1 mm
- Very large, from 1 to 2 mm
The presence of sand makes the agricultural land easily permeable and workable. However, it must be said that its excessive presence poses fertility problems. The sand, in fact, does not retain water and mineral salts, elements necessary for plant nutrition.
Clay
Contrary to popular belief, clay represents the finest element of the soil. It has high colloidal properties, that is, it is made up of very small minerals that cement themselves together, giving life to a very compact and hardly permeable layer. The tendency of agricultural soils that are too clayey is to cause water stagnation and root asphyxiation. This creates problems with the physical fertility of the soil.
On the other hand, clay has the ability to retain nutrients and therefore improves biological fertility.
Ħamrija
Silt represents fractions of soil with characteristics intermediate to those of sand and clay. In particular, the larger silty ones have properties similar to those of sand, the finer ones to those of clay, with the exception of colloidal properties. The silt, in essence, has the strengths and weaknesses of sand and clay, and these, in part, compensate for themselves.
Soils with a lot of silt are of difficult agronomic management and pose problems of physical and mechanical as well as biological fertility.
humus
Humus represents the organic component of agricultural land. It is the most fertile part and derives from the ripening and decomposition processes of the organic substance.
The presence of this element gives fertility to the soil, which is able to better retain water and nutrients.
To understand it better, we recommend these insights on trobbija tad-dud u l-ħumus tal-ħniex.
Land classification
Soils can be classified in various ways, depending on the elements present. There are medium-textured soils, sandy or loose ones, clayey ones, silty ones and humiferous ones.
Medium-textured soil
This type of soil has fractions of sand, silt and clay in such quantities that none prevail over the other. The medium-textured soil is the best for those who practice agriculture, as it creates the ideal conditions for the balanced development of plants.
The texture of this type of soil usually consists of:
- 50-70% sand
- 25-40% silt
- 5-15% clay
- Percentages higher than 2% of humus
- Negligible skeleton
In the presence of such terrain, the goal is to maintain the structure. This is achieved with limited processing, constant and not excessive supply of adequate organic substance rotazzjonijiet tal-għelejjel, irrigazzjoni taqtir. In addition, soil conservation agronomic techniques such as mulch naturali.
Sandy or loose soil
The sandy soil is composed of a quantity of sand higher than 70% and clay always lower than 30%. As mentioned, if there are high percentages of sand, the surface is easy to work with, has excellent permeability, is well ventilated and heats up quickly.
At the same time, however, this type of soil is not very fertile. The distance between the constituent particles, in fact, makes it difficult for the nutrients to stay in the upper layers useful for the roots. Sandy soil also needs frequent watering, especially in summer. To correct and improve it, a high intake of organic substance is recommended, for example through mature manure or organic manure (which jinstab hawnhekk).
You can also opt for a massive use of kompost tad-dar.
Clayey soil
Clayey agricultural soils are those in which the clay content is on average higher than 45%.
They are defined as “heavy”, due to the difficulties in processing and the tendency to retain too much water, giving rise to water stagnation. As we know, these stagnations can be a major problem for most crops. They often cause stunted growth and lead to rot and disease.
As we have mentioned, however, clayey soils retain nutrients as well as water. This feature greatly increases the fertility of the soil, a virtue that can be exploited with the necessary precautions. For example, it is possible to carry out drainage or draining operations of surface water.
To improve the structure of the earth, it is also recommended in this case to add organic matter before processing. It is also advisable to add river sand, in order to compensate for the excessive presence of clay.
Loamy ground
A soil is considered loamy when it has a quantity of silt higher than 80%. These are soils in which it is difficult to cultivate, where very hard clods and tenacious superficial crusts are formed. They have very low permeability and generate water stagnation and root asphyxia. They are also nutrient-poor soils, unlike clay soils, which are compact but rich.
The loamy soil is easily recognized, as it is very dusty when the climate is dry. On the other hand, in the presence of water it turns into mud and has a soapy consistency.
Unless major structural interventions are carried out, farming in this type of land is not recommended.
Humiferous soils
Finally we have the humiferous soils. Basically, they are those soils in which the content of organic matter exceeds 10%. In nature they are usually represented by wooded, peaty soils.
In peasant practice, it is those lands that are managed correctly, with a constant supply of organic substance and that undergo non-intensive cultivation practices.
The composition of the agricultural land
Hemm composition of the agricultural land it depends on several competing factors. The main factor is the nature of the soil itself, therefore the consistency of the pedo-genetic substrate and the ways in which its formation and evolution took place. A second factor is represented, in cultivated land, by the agronomic practices to which these are periodically subjected.
In the agricultural soil there are living organisms and dead organic components, in different stages of decomposition and transformation. Basically we’re talking about what we normally know as organic matter of the soil.
Organisms must be considered at the same time as inhabitants of the soil and as organic components that determine its fertility.
Pjanti
Among these we have first of all the plants, which penetrate the mineral complex of the soil with their roots, enrich it with organic substance and improve its structure.
A bare soil is certainly poorer in organic matter than a soil with adequate vegetation cover.
annimali
Then there are the animals (earthworms, worms, millipedes, moles, rodents, insects, mites, gastropods). These mainly provide for the breaking up of dead plant organs. Earthworms have a particular importance in this function, which operate a real channeling of the soil, mixing it and enriching it with organic substance, thanks to their digestive secretions.
As we know, the transformation activity of the organic substance of these annelids is exploited in specialized farms for the production of the famous ħumus tal-ħniex.
Bioreducer microorganisms
The organic substance that determines the composition of the agricultural soil also includes bio-reducing microorganisms. These decompose the organic residues of plants and animals present in the soil, until all the organic substance is oxidized and mineralized, i.e. transformed into inorganic compounds (carbon dioxide, water, mineral substances).
The main representatives of microorganisms living in the soil are: bacteria and fungi.
Batterji
Rizobi
The bacteria present in the soil constitute the main mass of microorganisms and are present above all in well-ventilated types of soils and with pH alkaline to slightly acidic. They feed mainly on easily decomposable substances, rich in carbon and nitrogen. In favorable environments, they reproduce very quickly.
Many bacterial species play an essential role in nutrient cycles. An example is that of riżobijabacteria that work in symbiosis with the roots of leguminous plants. These are able to fix atmospheric nitrogen in the soil, thanks to the action of a particular endogenous enzyme, the nitrogenase.
With symbiosis, a positive flow of nutrients is established between the two partners (plant and bacterium). This also increases the fertility of the soil: thanks to agronomic practices such as demel aħdar the nitrogen fixed in the soil will be available for subsequent crops.
Another particular order of bacteria present in agricultural soil are the aktinomiċetivery active when the soil is poor in oxygen (anaerobic conditions).
Faqqiegħ
Other microorganisms that contribute to the composition of the agricultural soil are i faqqiegħ. The more difficult the decomposition of plant residues and the more acidic the soils, the more intense their bio-reducing activity (heterotrophic plants).
Some groups of fungi specialize in the decomposition of lignin and its transformation into simpler compounds.
Many others live in symbiosis with the root systems of plants, generating positive effects; an example are mycorrhias.
Other fungi, on the other hand, are plant parasites and can cause serious damage, such as root rot and del necklace.
humus
The non-living organic substance present in agricultural soil is called humus.
Mineral compounds
As mentioned, in addition to the organic substance, the composition of the agricultural soil is due to the presence of mineral compounds. These are essentially made up of silica and silicates of aluminum, potassium, iron, magnesium. They can be present in large crystals (sand) or in smaller particles, with colloidal behavior, arranged in thin layers (mineral clays).
The degradation of silicates releases elements such as aluminum, iron, manganese and others that are found in the soil in the form of oxides and hydroxides.
Other elements such as nitrogen, phosphorus, potassium, magnesium, sodium and chlorine are present in the form of salts. These are partly soluble in soil water and partly insoluble.
Always present are alkaline-earth carbonates such as limestone (CaCO3), magnesium carbonate (MgCO3) and dolomite (CaMg (CO3) 2).
The content of limestone and soluble carbonates (active limestone) influences the structure of the soil, the chemical properties (pH, buffering power) and the absorption of nutrients by plants. The more calcareous the soils, the more difficult it is for plants to absorb nutrients.
Konklużjonijiet
We have come to the end of this article dedicated to the classification of soils based on their physical structure. In a future study we will talk about the chemical reaction of the soil, explaining the difference between acidic, neutral and alkaline soils. Another element to make the right cultivation choices.
Ibda Thread ġdid