Soil in everyday life means land areas on which variety of works such as agriculture, housing, and so on can be established. While for agriculture, soil has a special meaning, which is a natural medium for plants’ growth. Soil is the result of evolution, has a unique and organized arrangement and consists of layers or horizons that develop genetically. Vertical cross section of the soil shows the structure of the soil horizon called the soil profile. Constituent of the soil profile from top to bottom respectively are O, A, B and C horizons; and so called solum is A and B horizons (Fig beside).
O horizon is an organic horizon formed on the top layer of mineral soil, found mainly in forests soil that has not been disturbed. A horizon is the surface soil horizon which consists of a mixture of organic and mineral materials and is the eluviations horizon (experienced leaching). B horizon is an accumulation horizon (illuviation) of materials leached from above layer (clay, Fe, Al, organic matter). While C horizon is the parent material (regolith) that is slightly weathered (soft).
For citrus, soil is a place to stand upright, to take nutrients and water, and to exchange nutrients between soil and plant roots. Citrus has wide adaptability towards physical and chemical characters of soil. However, the ideal soil physics are has deep soil layer (> 75 cm), texture of sandy to sandy loam, good drainage and aeration, and the depth of the ground water level of about 100 cm. While ideal peat soil is the peat soil that has largely decayed (sapric), and the depth of pyrite should be more than 150 cm from the soil surface. While the ideal chemical character of soil, among others are, pH of about 6.5, cation exchange capacity of more than 25 me/100 g soil, base saturation > 50%, and the salinity of less than 2 mmhos/cm, and mineral soil’s carbon organic content of about 3-5%.
Author : Sutopo
Translated by : Tyas