Effects of different sources of silicon and irrigation regime on rice yield components and silicon dynamics in the plant and soil

Abstract

The amount of monosilicic acid, plant absorbable silicon, released from fertilizers can be influenced by silicon source and soil properties. A pot experiment was conducted to investigate the effects of different sources of silicon application on rice under different irrigation regimes in 2018. The treatments included two Si doses (250 and 500 kg Si ha−1 as potassium silicate (Ps), sodium silicate (Ss), calcium silicate (Cs) and biochar (Bi) sources) under two irrigation regimes (continuous flooding (W1) and irrigation when perched 70% field capacity (W2)) in two soil series with different textures (sandy-loam (S1) and silty-clay (S2)). The experiment was laid out in a split-factorial design with three replications. The results showed that S1W1Bi1 and S2W1Ps1 treatments were the best treatments to reach maximum plant height, the number of tiller and 1000 grain weight. The highest silicon content of stem (52.1 mg Si kg−1), leaves (87.5 mg Si kg−1) and paddy (95.5 mg Si kg−1) was observed in S2W1Ps1 treatment. Based on these results, a yield depression was observed at the higher Si rates (500 kg ha−1 compared to 250 kg ha−1) in fertilizer treatments of potassium and sodium silicates in sandy-loam soil under W2 irrigation regimes. After harvest of rice, the highest residual Si concentration in both soils (S1: 82.0 mg Si kg−1; S2: 145.6 mg Si kg−1) was found in Ps1W1 treatment compared with the control. In conclusion, biochar and potassium silicate treatments showed the highest increase in growth and yield components in S1W1 and S2W1 conditions, respectively.