Cumulative effects of urea and ammonium sulphate on the ninth-year grown on reddish brown lateritic soil
1994
Amnat Suwanarit | Jarong Rungchong | Suparb Buranakarn (Kasetsart Univ., Bangkok (Thailand). Faculty of Agriculture. Dept. of Soil Science)
Field plot experiment was conducted on a Packchong soil series (Reddish Brown Lateritic Group or Oxic Paleustult) at the National Corn and Sorghum Research Center to examine cumulative effects of repetitive annual applications of urea and ammonium sulfate on corn grown in the nineth year. The fertilizers had been applied at the rate 0, 60, 120, 180 and 240 kg N ha/year. Phosphate ferilizer had been applied annually as basal fertilizer. Zinc chloride had been applied as basal fertilizer in some years. At the highest rate of N fertilizer, 240 kg N ha/year, ammonium sulfate gave higher grain yield than urea but showed only a trend to give higher stubble yield of corn than urea. However, at the other rates of application the two kinds of fertilizers were comparable in grain an stover yields of corn. The amounts of N in grain and the total amounts of N in corn obtained with the two kinds of fertilizers were comparable at all rates of fertilizer. The results suggested that the difference in grain yield was not due to the availability of N containing in the fertilizers but due to other properties of the fertilizers.
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