ZHOU Zhi-hong1,2, LEE Xin-qing 1, XING Ying 1,2 , FANG Bin1,2, ZHANG Li-ke1,2, PENG Yan1,2
(1.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China;
2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China)
Abstract: Leaching loss is a factor leading to nutrient depletion in soil, and also a major approach to the eutrophication of aquatic environments. How to slow down the nutrient loss in soils is to improve the utilization efficiency of chemical fertilizers, but also to prevent water environments from being polluted. The effect of Biochar on nitrogen leaching was examined in this study by amending the Chernozem and Purplish soils with charcoal from corn stover. The charcoal was mixed in soils at the equivalent rate of 10 t/ha, 50 t/ha and 100 t/ha, urea was applied in the top soil at the rate of 240kg N/ha. The soil treatments were watered at the increment of 10mm precipitation everyday. The analyses of the leachate showed that the leaching loss of total N in the control treatment accounts for 7.5% and 9% of the N inventories in the Chernozem and Purplish soils, respectively. The loss occurred predominantly in the first 130mm precipitation, and the leachate was composed mainly of organic N and nitrate N, each of which constitutes 48%. Biochar application can reduce the leaching loss significantly. The loss of total nitrogen in the Chernozem was reduced by 29% and 74% at 50 t/ha and 100 t/ha application rate, respectively, while 41% and 78%, respectively, in the Purplish soil. The loss was enhanced, however, at 10 t/ha application rate by 22% and 2% in the Chernozem and Purplish soils, respectively, suggesting that the low application rate of charcoal will exacerbate N leaching. The amelioration effect of charcoal on the leaching of organic N is stronger than that on the leaching of nitrate-N, by 88% vs 62% on average at 100 t/ha application rate. These results provided the basis for developing technologies to prevent the leaching loss of soil nitrogen.
Key words: biochar; black carbon; nitrogen cycle; synthetic fertilizer; leaching loss
EARTH AND ENVIRONMENT Vol. 39, No.2, Tot No.283, 2011, Page 278
