By far the majority of the world’s potash production is utilized in agriculture. Over 97% of all potash is sold to improve the world’s food, fiber and other farm output. Potassium is one of the three major plant nutrients, and as such must be added to all intensive farming soils in comparatively large amounts for high crop production. Once the soil becomes depleted of any of the 16 or so necessary plant nutrients each must be added in equal amounts to the plants’ uptake. With all but the three major nutrients, nitrogen, phosphorus and potassium, however, the quantities are somewhat less, or very small (they are called secondary or micronutrients). Nitrogen may be provided to the soil through crop rotation and the action of legumes with their root nodules’ nitrogen (from the air)-fixing bacteria. However, the phosphate and potassium must either be in the soil or supplied externally in the amount required by the plant. Many potash-containing minerals such as clay, feldspar and mica are found naturally in soils. Some of their potassium content becomes available to plants with weathering, and consequently many soils have been slow to become depleted in potash. Consequently, the addition of potash may not be as demanding as the other nutrients with some crops or soils. Also, the placement of the potash is important in many soils since the potassium may be ion exchanged with clays or organic matter near the surface, and thus not be very mobile.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Utilization of Potash in Agriculture
PhD Donald E. Garrett
- Springer Netherlands
- Chapter 8
Fallstudie Überschwemmungskarten/© Thaut Images | Fotolia