Efficiency of fertilizer nitrogen as influenced by inhibiting nitrification with thiourea
1987
Witthaya Masena | Thongpan Nonrucha (Khon Kaen Univ., (Thailand). Faculty of Agriculture. Dept. of Soil Science)
This tracer experiment was designed to study the effects of Thiourea at different concentrations on the availability and efficiency of fertilizer N applied to lowland rice as urea -15N. The results showed that Thiourea inhibited nitrifying activity of the nitrifiers which reflected in the increased availability and efficiency of fertilizer nitrogen to the rice plants. However, levels of Thiourea used did not cause the contrasting effect within the same soil, but among different soils. Of the total nitrogen absorbed by the rice plants during growth, 77.22-86.24 came from soil while 13.76-22.78 % were fertilizer nitrogen. Without Thiourea, the efficiency of fertilizer nitrogen was 21.25-28.71 % when Thiourea was applied, however, the efficiency was increased to 28.25-39.91 % varying among the soils studied but without significant effects of levels of Thiourea within the same soil. Thiourea and Nitrapyrin indicated similar potentiality as nitrification inhibitors for the two lowland soil of Northeast Thailand used in this study.
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