This is the time when you can best evaluate what type of soil you have in your garden or allotment. This is important because certain plants have a preference for a particular type of soil, while the others will recede. We will discuss about certain important features of the soil like: profile, texture, pH, fertility and living organisms. The quality of the soil determines the quality of your products.
The profile of the soil is the represented by several different layers:
In the left picture you are shown a soil profile or a grass land. This is not the ideal profile that you like to have in the garden, because the humus layer is not thick enough (the darker part). The deeper you go, the lighter the soil it gets. This is because deep soil lacks organic matter.
The texture of the soil may or not be identical in a garden. It all depends on the plants that were previously cultivated, the original features and the improvements given to the soil. The size of the particles forming the soil determines its texture. From this point of view we may classify the soil into three categories: clay soils, sandy soils, loamy soils.
Look at your soil, take some samples. If you can make out of your soil a sphere, and while you shaping it you are reminded of Plasticine then you most probably have a clay soil. If it is sandy it loses shape immediately and if you have loam you will see that it is crumbly and the surface of your sphere is not regular.
pH. Is your soil alkaline or acidic?
pH measures whether your soil is bitter or sour, alkaline or acidic. pH is measured on a scale from 0 to 14. The lower the pH value, the more acidic the substance, the higher the value the more alkaline the substance is. For instance, lemon juice has a pH of 2, orange juice a pH of 3 and tomato juice a pH of 4, while sea water has a pH of 8, backing soda of 9, bleech of 13. The neutral value stands at 7. That is the pH of distilled water.
Because of the composition of the soil, normally, the garden soils fall between 4.5 and 7.5. Certain plants, like Hortensias, Rhododendrons and Azaleas prefer rather acidic soils, others, like cabbages, more alkaline. Most of the garden plants flourish at pH of 6.5, so a very slightly acidic soil. While is relatively easy to increase the pH of the soil by adding lime, the things are not so simple when you desire to lower the pH.
The pH of the soil is important because the plants are able to absorb nutrients they need only under specific pH conditions. If the pH is too high or too low, certain nutrients, even if they exist in the soil, they practically unavailable to the plants. The attached diagram shows the availability of certain nutrients according to the pH of the soil.
Fertility of the soil is determined by five aspects: air, water, pH, organic matter and mineral nutrients. A fertile soil is rich in major nutrients (nitrogen, phosphorus and potassium), has sufficient quantities of mineral nutrients also called minor or oligo-nutrients (boron, chlorine, cobalt, copper, iron, manganese, magnesium, molybdenum, sulphur, and zinc), it has a good pH (usually 6.5). It is rich also in organic matter which has the capacity of making the soil lighter, easier to cultivate and contributes to drainage and water retention. A fertile soil is not only able to retain water but also has the capacity to avoid waterlogging. Air is important for the developing of the roots. Without air, the roots simply suffocate and then rot and the entire plant is compromised.
The profile of the soil is the represented by several different layers:
- The highest layer may be litter, this is clearly seen in the forests and it is the result of falling leaves and other parts of the plants living in the area.
- Just under the litter it is the humus. It is usually darker, finer and well drained. It is composed mostly by mineral parts and organic parts. Most of the organic part of the soil is found in the upper layer, ideally somewhere between 60 – 90 cm.
- The upper layer is a mixture of organic and inorganic matter, lighter in colour less fertile. The roots of the plants are digging through this layer looking for food, still.
- Underground it is the lower part of the soil. It is more compact, it may contain stones or water, it lacks aeration and roots receive less oxygen. Most of the fruit trees expand their radicular system into this layer.
- Underground may rest of different type of rocks which are impenetrable and they do not offer a source of food. Sometimes the roots of the tress may go around the blocks of stone to seek support. In other parts, near the rivers, this part may be always waterlogged and the survival of the roots of the plants is impossible.
In the left picture you are shown a soil profile or a grass land. This is not the ideal profile that you like to have in the garden, because the humus layer is not thick enough (the darker part). The deeper you go, the lighter the soil it gets. This is because deep soil lacks organic matter.The texture of the soil may or not be identical in a garden. It all depends on the plants that were previously cultivated, the original features and the improvements given to the soil. The size of the particles forming the soil determines its texture. From this point of view we may classify the soil into three categories: clay soils, sandy soils, loamy soils.
- Clay soils
Are composed of very fine particles of sand of the size of 2 microns. This is about 100000 times smaller than a normal grain of sand. These soils are heavy, they tend to be on the wet side and they keep water and nutrients very well. The drawback is that they are compact and difficult to work and many of the plants will have difficulties in developing their roots. Also during the dry spells, the soils tend to dry forming light grey rocky blocks, difficult to break apart. They have a tendency to waterlogging and extra-care should be given to the overwintering plants, because it facilitates rotting of the roots. In addition they warm up slowly during the spring and seed germination is delayed. - Sandy soils
They are just the opposite of the clay soils. They are composed mostly of sand, which has the capacity of being airy and oxygen reaches easier the roots of the plants. However they have a low water and nutrient retention. Certain root plants (like carrots, or potatoes) will flourish in these grounds provided that they receive regulate feeding and watering. They warm up quickly during the spring and they can be worked easy.
- Loamy soils.
They are crumbly rich organic grounds, with good water retention and light structure. They are the best soil you can have in your garden, because they are composed of a good ratio of humus, clay and sand.
The ideal soil for the garden is composed of 65% sand, 10 % lime and 5 % humus. It is supple, crumbly, easy to work, had good water retention without the risk of becoming waterlogged.
Look at your soil, take some samples. If you can make out of your soil a sphere, and while you shaping it you are reminded of Plasticine then you most probably have a clay soil. If it is sandy it loses shape immediately and if you have loam you will see that it is crumbly and the surface of your sphere is not regular.
pH. Is your soil alkaline or acidic?
pH measures whether your soil is bitter or sour, alkaline or acidic. pH is measured on a scale from 0 to 14. The lower the pH value, the more acidic the substance, the higher the value the more alkaline the substance is. For instance, lemon juice has a pH of 2, orange juice a pH of 3 and tomato juice a pH of 4, while sea water has a pH of 8, backing soda of 9, bleech of 13. The neutral value stands at 7. That is the pH of distilled water.
The pH of the soil is important because the plants are able to absorb nutrients they need only under specific pH conditions. If the pH is too high or too low, certain nutrients, even if they exist in the soil, they practically unavailable to the plants. The attached diagram shows the availability of certain nutrients according to the pH of the soil.
Fertility of the soil is determined by five aspects: air, water, pH, organic matter and mineral nutrients. A fertile soil is rich in major nutrients (nitrogen, phosphorus and potassium), has sufficient quantities of mineral nutrients also called minor or oligo-nutrients (boron, chlorine, cobalt, copper, iron, manganese, magnesium, molybdenum, sulphur, and zinc), it has a good pH (usually 6.5). It is rich also in organic matter which has the capacity of making the soil lighter, easier to cultivate and contributes to drainage and water retention. A fertile soil is not only able to retain water but also has the capacity to avoid waterlogging. Air is important for the developing of the roots. Without air, the roots simply suffocate and then rot and the entire plant is compromised.
The soil is a true ecosystem by being the siege of intricate alimentary chains. The organisms in the soil participate actively in furnishing a good quality soil by their way of feeding themselves. The woodlouse, myriapoda, larvae of the flies and termites are fragmenting the organic matter. Certain mites, springtails and termites continue the fragmentation of organic matter in even smaller compounds. Beetles and their larvae, fungi, nematodes, worms and bacteria continue the fragmentation to even simpler compounds, making them available for the roots of the plants. At the same time ants, moles, slowworms, voles, termites are digging and making small tunnels in the ground, making it more airy. However some of these organisms may prove to be dangerous itself. Snails are feeding themselves on the crops but they are enriching the humus with organic matter once they are dead. Earthworms, although they are not directing menacing the crops, while they are digging tunnels underground can bring diseases and viruses to the roots of the plants. On the market exist a large assortment of chemicals destined to destroy all the insects in the ground, however this not ecological, and on long term these chemicals unbalance the healthy ecosystem of the soil.
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