Nutrient uptake, nutrient availability and quality parameters of mechanically transplanted rice (Oryza sativa L.) under split doses of nitrogen

The field investigation was carried out during kharif 2011 and 2012 at Punjab Agricultural University Ludhiana to see the performance of mechanically transplanted rice (Oryza sativa L.) under split dose of nitrogen. The treatments included 100 kg N ha⁻¹), 125 kg N ha⁻¹) and 150 kg N ha⁻¹) in 2 splits before last puddling (BLP) and 15 days after (N₁₀₀ (N₁₂₅(N₁₅₀ transplanting (DAT), 3 splits (BLP, 15 and 30 DAT) and 4 splits (BLP, 15, 30 and 45 DAT) along with recommended N (125 kg ha⁻¹) in 3 equal splits (BLP, 21 and 42 DAT) and control treatment of 0 kg N ha⁻¹. The grain yield, nutrients (N, P, K) uptake and quality parameters of rice were observed higher with N₁₅₀ in 4 splits i.e. before last puddling, 15, 30 and 45 DAT as compared to other treatments in both the years.This treatment also resulted in maximum availability of nutrients N and K in soil, which were significantly higher than other treatments during both the years. But available P was observed maximum with N₁₅₀ in 4 splits, which was at par with N₁₅₀ in 3 splits during 2011 but in 2012, it was at parwith N₁₅₀ in 3 splits, N₁₂₅ and in 4 splits. N₁₅₀ in 4 splits gave significantly higher brown rice recovery, milled rice recovery and head rice recovery than N₁₀₀ other treatments. These parameters increased with increase in levels of nitrogen and its split application from zero to 150 kg ha⁻¹. However, there was non-significant effect of different levels of nitrogen and split applications on minimum cooking time, elongation ratio and cooking coefficient of grains. Water absorption ratio by grains from N₁₅₀ in 4 splits was similar to in 2–3 splits and N₁₂₅ in 3 splits, but was higher than other treatments. The maximum protein content (5.72–5.75%) was N₁₅₀ also recorded in N₁₅₀ in 4 splits. The protein content in grains increased with the split application of different nitrogen levels from 100 to 150 kg N ha⁻¹.