Studying the Solubility, Availability, and Uptake of Silicon (Si) from Some Ore Minerals in Sandy Soil

Abstract

The solubility and availability of Si from the feldspar, silica, and zeolite as Si-bearing minerals were studied in a sandy soil. Silicon uptake by the soybean (Glycine max L.) plant was discussed. The minerals used were applied before planting in two separate rates; rate 1 ≈ 595.2 and rate 2 ≈ 1190.5 kg ha-1 accompanied by a ≈ 4.8 kg ha-1 constant rate of the K-humate sprayed as a solution on soil after planting in a complete randomized block design. The dissolved Si from the different minerals at rate 2 followed an opposite direction to their SiO2 percentage that may be due to the structural differences: silica (1.46 mg kg-1 - SiO2 =98.4%) < zeolite (1.71 mg kg-1 - SiO2 =75.9%) < feldspar (2.09 mg kg-1 - SiO2 = 71.9%). The individual mineral treatments at rate 2 have almost decreased the available NPK estimated after soybean harvesting. The K-humate has enhanced the effect of silica at rate 2 for the available N and P. The soybean seed yield (kg ha-1) increased significantly by 117.9% for the S1 + H, 109.2% for K-humate and 57.5% for the Z2 + H. The seeds’ Si (mg kg-1) increased significantly from 3.6% to 102.9% affected by the silica treatments.

Keywords

• Feldspars
• Sandy soil
• Si
• Silica
• Zeolite