The term soil indicates a soil that is particularly rich in nutritive elements (usually vegetable substances in a state of decomposition) derived from the countryside, from the woods or from the composting of the organic part of the garbage and solid waste; this soil is mixed with other substances, and then used as fertilizer or fertile substrate for gardening plants, pot plants and greenhouses. Evidently, the etymology refers to the earth, that is to say to the soil in which the plants grow. In reality, the soil is composed of three parts: a vegetable part, consisting of plant residues and leaves; an inert, draining and structuring part, consisting of pebbles, gravel and sand; and finally a clayey part, consisting of silt or clay, more or less compact. Each of these parts, however, can be subjected to other distinctions concerning the physical nature, origin and chemical origin. But actually making too sharp distinctions would be wrong, because, for example, the plant component can be nourishing inside the clay, while the clay itself can look like sand, and so on. The fact remains that from the combination of the different parts descend physical conditions of water release, water retention and particular humidity, but also nutrients, both inorganic and organic. Furthermore, each soil is characterized by a specific pH, that is to say by a specific value of alkalinity and acidity.
From the point of view of the cultivation of plants, it is possible to identify a practically infinite range of soil, given that each plant species shows specific needs from this point of view: in fact, we will have plants that prefer draining soils and plants that prefer compact soils; plants that prefer alkaline soils and plants that prefer acid soils; and so on, without forgetting other peculiarities such as the richness or lack of nutrients and the ability to retain liquids. In addition to the main nutrients, corresponding to potassium, phosphorus and nitrogen, it is necessary to remember the so-called mesoelements, whose role is fundamental in the exercise of catalytic, chemical or physical functions, but above all the microelements, which, although present in minimal quantities, are reveal indispensable to guarantee the survival of the plants. It is also worth remembering that the mycetic and bacterial population is used to start important chemical transformations, to make nutrients available and above all to favor the condition of soft soil. About the cultivation soil, in the field of gardening the products used derive from the composition of different elements. It is essential to be aware of the needs of different plants, so as to adapt soil conditions to growth. It is above all at the time of sowing that the preparation proves to be important, when the availability of nutrients and the retention of liquids are relevant for the emergence of the stems (and in general for the first life stages of the different species). the softness of the soil and the ability to preserve moisture.
The uniformity of the soil, moreover, has increased the availability of peat, a compound deriving from the plant decomposition that exerts a major action in reducing infections. It is no coincidence that peat is rarely used for adult plants, which do not need to conserve moisture so clearly (or even to protect themselves from disease through external help): consequently, in these cases it can be done use of less expensive soil improvers. It should be noted, moreover, that the increase in the use of peat, due to the very substantial truth, has given rise to considerable problems of eco-sustainability, given that peat bogs are gradually running out: to find an immediate solution, a balanced management that manages to reconcile the natural restoration of peat bogs and their cultivation.
On the market
On the market, the soil is available in different forms: from medium to universal soil, to soil for basophilic plants; from loam without clay to soil for acidophilic plants. Furthermore, there are also products containing earthworm humus, for essences with specific needs. The chestnut soil, for example, is made of chestnut wood cut into pieces by a particular caries that is kept inside old trunks in a powdery form, while the woodland soil is obtained from woods that include deciduous trees, and can be stored in damp and cool places. The most widespread natural substrate remains, of course, garden soil, used for numerous herbaceous, shrub and tree species grown in parks and gardens. As a rule, it is considered of good quality a well-worked soil, sufficiently fertile, without pieces of roots or pebbles, able to favor an excellent drainage and therefore a regular water flow: a means to prevent the appearance of water stagnation and therefore the onset of rot due to humidity. The garden soil, commonly, consists of clay, silt, organic substances in the decomposition phase and sand. The compost, on the other hand, is particularly suitable for the cultivation of flowers: it is a product with a high content of nutrients, obtained by mixing manure and earth in equal parts.