AEROBIC RICE'S YIELD PERFORMANCE AND NITROGEN USE EFFICIENCY UNDER VARIOUS NITROGEN FERTILIZER RATES
Journal: i TECH MAG (Research Article)
Author: Zaki Musa
This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Aerobic rice, a water-saving cultivation system rice could thrive well in rain-fed areas in Sarawak which lacks in drainage and irrigation system, with appropriate fertilizer management practices. Since nitrogen (N) as a major determinant factor in rice yield is required differently based on cultivation system, soil and other in-situ conditions, a study was conducted to determine the optimum N fertilizer rate while assessing nitrogen use efficiency of aerobic rice in Lundu, Sarawak. Four N fertilizer rates (T1=0, T2=100, T3=200 and T4=300 kg N/ha) were tested with split application of urea (46% N) at 23%, 31%, and 46% at 5, 25, and 45 days after emergence (DAE) using MRIA1 variety. The findings indicated that an increase in N fertilizer of more than 100 kg N/ha had no discernible impact on yield. The highest yield recorded was 3.31 t/ha in T2 and decreased to 2.99 t/ha and 2.86 t/ha respectively in T3 and T4, while T1 recorded 1.12 t/ha. Meanwhile, significant differences in partial factor productivity (PFPN), agronomic efficiency (AEN), apparent recovery efficiency (REN) and physiological efficiency (PEN) were observed between the treatments with descending efficiency trends at higher N fertilizer rates. Optimum NUE values were recorded in T2 with PFPN = 29.30 kg/kg; AEN = 14.56 kg/kg; REN = 0.26 kg/kg; and PEN = 55.64 kg/kg. Therefore, it can be concluded that 100 kg N/ha is recommended for aerobic rice cultivation in Tanjung Purun, Lundu, as yield and NUEs were optimized.