Quantitative field evaluation of Malaysian-made formaldehyde treated granular urea for Nicotiana tabucum L., using lsN isotope aided technique

K. C. Tham. W. I. Wan Azman. K. Harun and B. Kadmin

Abstract

Ther esponsbey tobaccoto formaldehydtere atcdg ranulaur rca( viz.2 .0-2.8 mm Ø and 6.0-8.0 mm Ø and NH₁NO₃ were compared under traditional management of two season (Rusila soil series) and regularly sprinkler irrigated (Rhu Tapais oils cries) conditions using ¹⁵N isotope labelling technique.  Treatment receiving granular urea consistent had hidher and yield and lower percentage ¹⁵N atom excess - indicating a higher efficiency than treatment receiving NH₄NO₃ althougha these were not significant (p :0.05) at any one location. None of the commercial fertilizer sources tested had any significant effect on dry matter, yield. In terms of efficiency expressed in equivalen sttandard ^₁₅N fertilizer units, granular real consistently supplied higher a mounts of plant available N than did NH₄NO₃. The effects were however significant (p :0.05) only at Bachokin 1986 where LGU and SGU supplied approximately 1.3 times more plant available N than did NH₄NO₃. Uptake of commercial fertilizer  source as measured in the plant tops was highest with LGU and lowest with NH₄NO₃ under both management conditions although these difference were not significant (p =0.05). None of the commercial N fertilizer source had any significant effect on the crop index or  the percentag neon-descript of the flue-cured tobaccoa at Rantau Abang.

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