Soil and Plant Silicon and Silicate Response by Sugar Cane

Abstract Calcium silicate slag increased sugar yields 12 tons/hectare in a field where phosphate extractable soil silicon and trichloroacetic acid (TCA) extractable silicon of sugar cane (Saccharum officinarum) leaf sheaths were about 20 ppm. Large amounts of P or lime did not alleviate leaf freckle whereas slag did so to a marked degree. Acid solutions of phosphate, sulfate, acetate, and water can be used successfully as extractants for soil silicon. The general order for extractable silicon from soils developed on basalt and alluvium was: Humic Ferruginous Latosol < Humic Latosol < Low Humic Latosol < Dark Magnesium clay. This is also the order of decreasing weathering for these soils as indicated by total soil silicon and occurrence of secondary minerals. Leaf sheath silicon (TCA extractable) was especially well correlated with log extractable soil silicon (r = 0.97 for water extraction). Irrigation waters may contain much silicon and contribute greatly to the supply of extractable soil silicon and to plant silicon.