The ideal agricultural soil composition by volume is 50% solid (45% clay, silt, sand, and 5% humus) and 50% voids (25% air and 25% water). Its pH should be between 6.5-7.5, non-saline, lime content between 5-10%, organic matter between 3-6%, loamy texture, inorganic nitrogen (NH4-N + NO3-N) more than 70 mg/kg, phosphorus 8-25 mg/kg, potassium 110-290 mg/kg, calcium 1,150-3,500 mg/kg, magnesium 160-480 mg/kg, sulfur more than 10 mg/kg, sodium less than 100 mg/kg, exchangeable sodium percentage less than 15, iron 4.5-10 mg/kg, zinc 0.7-2.4 mg/kg, manganese 14-50 mg/kg, boron 1.0-2.4 mg/kg, copper more than 0.2 mg/kg, dark-colored, deep, permeable, warm, and well-structured. There is a strong antagonistic (mutually inhibitory) relationship between the macro nutrients potassium, calcium, and magnesium. For plants to benefit maximally from these nutrients, the ideal ratios of Ca/K = 12, Ca/Mg = 6, and Mg/K = 2 should be maintained in the soil with me/100 g exchangeable cations unit. Similarly, there is a strong antagonistic interaction between the micro nutrients iron, zinc, manganese, and copper, where an excess of one inhibits the uptake of others. Therefore, the use of fertilizers containing these nutrients should be based on complete analysis results obtained from reliable laboratories.
High pH (7.5-8.5), high lime content (more than 15%), low organic matter (less than 2%), and heavy texture (clay, clay-loam).
