Nitrogen balance study using N-15 [Zea mays].
1985
Mohamad Khanif bin Yusop
The experiments to determine the recovery and balance of applied N were conducted during two consecutive seasons, on field grown with maize (Zea mays L.). The fields were located in the sandy area of Belgium. The experimental plots received the same N rates and other treatments as the rest of the fields. In the experimental plots, N-15 labelled fertilizer N was applied. Plant and soil samples were analysed for their N-14/15 ratio to determine fertilizer N recovery. In the first growing season, the amout of fertilizer N recovered were 41.1 and 25.8 kg/ha from the 83 and 113 kg N/ha applied respectively. In the second season, the amount of N recovered by the plants from the 65 kg N/ha applied was 54.7 kg N/ha. In the first growing season, the amount of fertilizer N recovered in the soil were 77 and 18 kg N/ha in Evergem and St. Laureins respectively. In both locations, the fertilizer N could be recovered at the 90 cm depth. The amount of N remaining in the soil in the second season was lower i.e. 6.8 kg/ha, and mostly confined to the top 80 to 30 cm. The amount loss were 10.2 and 24.3 kg N/ha in the two locations in the first growing season, and only 3.5 kg N/ha in the second growing season. The loss in the first growing season can be attributed to leaching and denitrification, while in the second season it is due to denitrification.
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