Diatomaceous earth as source of silicon on the growth and yield of rice in contrasted soils of Southern India

Abstract

Application of diatomaceous earth (DE) could improve the quality of soil, but its application in agriculture as a Si fertilizer requires additional research. Pot experiments were conducted with graded levels (0, 150, 300, 600 kg ha-1) of DE with recommended dose of N, P, K, in three types of soil (acidic, neutral and alkaline) from Southern India under two moisture conditions (field capacity and submergence) using rice as a test crop. The chosen DE consisted of biogenic silica, smectite, kaolinite and quartz. The grain yield was lower in plants grown in FC than in SUB moisture conditions regardless of the soil type and the DE added. Higher grain yield was observed with different DE applications under the SUB moisture condition in the three soils. The Si uptake increased for acidic and alkaline soils but not for neutral soil under the SUB moisture condition, whereas under the FC condition, the Si uptake was increased over the control only in alkaline soil. Increased nutrient and Si uptake was explained by the combination of physical and chemical properties of DE and was not only due to the contribution of amorphous silica. DE might be useful for improving the crop yield, but the soil composition and water regimes play a key role that influences the availability of nutrients in soils.