Effect of Reduced Rates of N, P and K on the Yield of Rice (<i>Oryza sativa</i> L.) and its Nutrient Uptake

Abstract

An experiment was conducted to study the yield response and nutrient uptake of rice (BRRI dhan30) to reduced rates of N, P and K from the recommended fertilizer doses (RFD). The experiment was laid out in a randomized complete block design with four replicates. There were ten treatments viz. T₁ (control), T₂ (RFD), T₃ (RFD - 20% N), T₄ (RFD - 40% N), T₅ (RFD - 20% P), T₆ (FRD - 40% P), T₇ (RFD - 20% K), T₈ (RFD - 40% K), T₉ (RFD - 20% NPK) and T₁₀ (RFD - 40% NPK). The recommended fertilizer doses of the crop were 100 kg N, 20 kg P, 40 kg K, 20 kg S and 3 kg Zn ha^-1. The highest grain yield (5.10 t ha^-1) and straw yield (7.02 t ha^-1) were obtained by applying recommended doses of fertilizers which were insignificantly different from those observed in the treatments where N, P and K were reduced at the rate of 20% from the recommended doses. Similar results were also found in case of P, K and S content and uptake by rice plant, while the variation for N was found significant. Overall results indicated that 20% reduction of either N or P or K from the recommended doses would not significantly affect the yield of rice.