Effect of Nitrogen Fertilizer Level on Yield, Nitrogen Efficiency, Urease Activity and Soil Fertility after Sugarcane Harvesting under Sandy Soil Condition

Abstract

The objectives of this research were to study the effects of different nitrogen fertilizer level on growths, yields, nitrogen efficiency, urease activity and soil fertility after sugarcane harvesting under sandy soil condition. The experiment was designed under Randomized Complete Block Design (RCBD) with three
treatments and four replications. There were three nitrogen rates i.e. 1) control group (0 kg/rai), 2) N at recommended rate (N1) and 3) double recommended N rate (N2). The results were indicated that plant height and stalk diameter were not significantly different between treatments. However, N2 treatment gave
significantly number of tiller and SPAD chlorophyll meter reading (SCMR) at 4 MAP (P<0.05) higher than N1 and control. Moreover, N2 treatment had the highest of cane yield (9.08 tons/rai) and stalk number (14,824 stalks/rai) (P< 0.01) compared with N1 and control group respectively. N2 treatment improved soil organic matter and available phosphorus but not soil urease activity while urease activity per N added ratio lower than N1 treatment. Thus, double recommended N rate not only increased cane yield but also nitrogen use efficiency in sugarcane production under sandy soil condition of Northeastern Thailand.