科研之友
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摘要
Studying the distribution and balance of residual fertilizer N is of great importance for the optimization of N fertilization strategies. In 2011, we conducted a field experiment under natural rainfall. The experiment served the flue-cured tobacco as plant material, containing five different fertilizer N (sourced from (NH4NO3)-N-15-N-15, with abundance of 10.28%) application amounts of 60, 90, 120, 150 and 180 kg ha(-1). This study was to investigate the distribution and balance of 2011-residual fertilizer N (abbreviated as N-15) in the 2012 tobacco-growing season. The amounts of the soil N-15 in different layers, the plant N-15 in different organs and the lost N-15 in 2012 season were observed. Results showed that averagely 5.4% of the N-15 were reutilized by the tobacco plants in 2012 season, 7.5% were leached by runoff and seepage, 73.1% were remained in the 060 cm soil layer, and 14.0% were lost via volatilization, or entering into the deeper soil layer below 60 cm. Of the total soil residual N-15, 47.3% were remained in the 0-20 cm layer. And of the total N-15 that absorbed by the tobacco, 52.6% were accumulated in the leaf. Higher N application amount in the previous season increased the risk of N-15 leaching in the succeeding season, while it also increased the plant N-15 reuptakes significantly (p<0.05). The reutilization rates of 2012-season tobaccos to the 2011-applied fertilizer N were ranged from 1.2% to 4.6%.
