科研之友
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摘要
Nitrate (NO(3)-) can contribute to surface water eutrophication and is deemed harmful to human health if present at high concentrations in the drinking water. In grazed grassland, most of the NO(3)--N leaching occurs from animal urine-N returns. The objective of this study was to determine the effectiveness of a nitrification inhibitor, dicyandiamide (DCD), in decreasing NO(3)- leaching in three different soils from different regions of New Zealand under two different rainfall conditions (1260 mm and 2145 mm p.a.), and explore the relationships between NO(3)--N leaching loss and ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA). The DCD nitrification inhibitor was found to be highly effective in decreasing NO(3)--N leaching losses from all three soils under both rainfall conditions. Total NO(3)--N leaching losses from the urine patch areas were decreased from 67.7-457.0 kg NO(3)--N/ha to 29.7-257.4 kg NO(3)--N/ha by the DCD treatment, giving an average decrease of 59%. The total NO(3)--N leaching losses were not significantly affected by the two different rainfall treatments. The total NO(3)--N leaching loss was significantly related to the amoA gene copy numbers of the AOB DNA and to nitrification rate in the soil but not to that of the AOA. These results suggest that the DCD nitrification inhibitor is highly effective in decreasing NO(3)- leaching under these different soil and rainfall conditions and that the amount of NO(3)--N leached is mainly related to the growth of the AOB population in the nitrogen rich urine patch soils of grazed grassland.
- 出版日期2009-12
- 单位中国科学院
