Nitrogen Use Efficiency of Upland Rice in Northwest Region

  • Nguyễn Văn Khoa
  • Phạm Văn Cường


     The efficiency of nitrogen fertilizer in upland rice variety “Nếp nương tròn” and the control variety LC93-1 was evaluated in a nethouse pot experiment at Tay Bac University in Son La city. The pots were filled with 5 kg of upland soil. Plants of two varieties were fertilized with five levels of nitrogen: 0 mgN/pot (N0), 200 mgN/pot (N1), 400 mgN/pot (N1), 600 mgN/pot (N3), and; 800 mgN/pot (N4). The experiment was designed in randomized complete blocks with three replications, each replication consisting of 3 pots. The result showed that increased amount of nitrogen fertilizer from 0 mg/pot (N0) to 800 mg/pot (N4) increased plant height, number of panicles/hill, number of filled grains/panicle, biomass and grain yield in both varieties. Increased level of nitrogenous fertilizer led to apparent increased nitrogen concentration in stems and leaves but litle in grains. However, the amount of nitrogen absorbed by stem, leaves and grains and the total amount of nitrogen increased with the increased level of nitrogen fertilizer applied. Nitrogen use efficiency (NUE), agronomic efficiency (AE), physiological efficiency (PE) and utilization efficiency (UE) of two varieties declined with increased amount of nitrogenous fertilizer. Highest utilization efficiency (UE) was obtained at low nitrogen level.

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