SHJ 17:2

Sugarcane is one of the most important crops for renewable energy and
biomass production which considerably exhausts the available macro-and
micronutrients in the soil especially nitrogen (N). Fertilization of N has been a
practice in sugarcane production to attain greater yield. However, excessive
application of N fertilizer can cause harmful effects on the environment aside from
the additional cost of production and lowers nitrogen use efficiency (NUE) in
sugarcane plants. Thus, this study was conducted to evaluate the NUE of
sugarcane at the early growth stage and determine the concentration of N in
different plant parts from the applied 15N-labeled urea. The experiment was laid out
in a randomized complete block design with five levels of N: T₁ – control, T₂ – 40 kg N ha^-1, T₃– 80 kg N ha^-1, T₄ – 120 kg N ha^-1 and T₅ – 160 kg N ha^-1. Results revealed that
regardless of days after ¹⁵N labeled urea application, significantly highest NUE of
sugarcane plant parts was recorded when N was applied at a lower level (40 kg N
ha^-1) which eventually translated to a significantly higher overall fertilizer NUE of
the plant among other treatments. Moreover, among the different plant parts,
sugarcane plant stalk tissues accumulated a significantly higher level of ¹⁵N
regardless of N levels.

Keywords: ¹⁵N isotope, nitrogen use efficiency, sugarcane, tracer technique