Effect of calcium silicate and need based nitrogen management in aerobic rice

Nitrogen (N) is an important component of rice cultivation system, especially where rice is grown under aerobic condition. This study examined the effects of Silicon (Si) and leaf colour chart (LCC) based N management on yield and N use efficiency in aerobic rice. A field experiment was conducted during wet season 2008 in sandy loam soil at Bangalore-north with split plot design. The treatments consist four main plots viz., control (No N), 60 Kg N ha⁻¹ (No basal + LCC-3), 90 Kg N ha⁻¹ (Urea 30 Kg N ha⁻¹ as basal + LCC-3) and 100 Kg N ha⁻¹ as urea (RDF) and two sub plots viz., with (calcium silicate at 2 t ha⁻¹) and without Si treated plots. Periodical LCC readings were taken and N was applied if the LCC value falls below the prescribed critical value. The results revealed that the highest grain yield was recorded with the application calcium silicate at 2 t ha⁻¹ and with 90 Kg N ha⁻¹ (Urea at 30 Kg N ha⁻¹ as basal + LCC-3) and it was on par with 60 Kg N ha⁻¹ (no basal + LCC-3) compared to recommended N (100 Kg N ha⁻¹) under aerobic rice. Higher fertilizer N-use efficiency was recorded with the application of Si and need-based N management using LCC-3 rather than recommended dose of fertilizer over control.