生物质炭对红壤中硝态氮和铵态氮的影响

Effects of Biochar on Ammonium Nitrogen and Nitrate Nitrogen in Red Soil

以生物质炭为0,5,10,20,30,40t/hm2的比例与土壤混合,采用室内土柱模拟方法,研究生物质炭对红壤中铵态氮和硝态氮淋溶的影响。结果表明:不同处理的土壤淋溶速率随着生物质炭添加量的增加而显著降低,不同处理土壤中铵态氮和硝态氮的穿透曲线具有相同的趋势。各处理CK、C5、C10、C20、C30和C40的铵态氮淋失率分别为38.33%,37.05%,34.91%,29.83%,28.28%和20.03%;硝态氮的淋失率分别为98.86%,96.49%,94.23%,90.21%,86.15%和83.46%。各处理CK、C5、C10、C20、C30和C40的铵态氮相对浓度(C/C0)的峰值为0.12,0.12,0.11,0.10,0.09和0.09;硝态氮相对浓度(C/C0)的峰值为0.36,0.35,0.34,0.33,0.32和0.32。除硝态氮的浓度峰值与容重呈正显著的相关性外,硝态氮和铵态氮的累计淋溶量和浓度峰值与土壤容重、孔隙度、有机碳、CEC及生物质炭量均呈极显著负相关。生物质炭能显著减少土壤铵态氮和硝态氮的淋溶速率,延长淋溶时间,减少累计淋失量。

The biochar was mixed with soils at the equivalent rate of 0, 5, 10, 20, 30 and 40 t/hm2 respec- tively in this study. The effects of biochar on the ammonium nitrogen and nitrate nitrogen leaching in red soil were studied with the soil column leaching method. The results showed that the leaching rate significantly decreased with the increase of bioehar application amounts. Breaking through curves of ammonium nitrogen and nitrate nitrogen had the same trend in the CK, C5, C10, C20, C30 and C40. The cumulative loss rate of ammonium nitrogen was 38.33%, 37. 05%, 34.91%, 29.83%, 28.28% and 20.03% respectively, and that of nitrate nitrogen was 98.86%, 96.49%, 94.23%, 90.21%, 86. 15% and 83.46% correspondingly. The peak values of ammonium nitrogen,s relative concentration （C/C0） were 0.12, 0.12, 0.11, 0.10, 0.09 and 0.09 respectively, and that of nitrate nitrogen were 0.36, 0.35, 0.34, 0.33, 0. 32 and 0. 32. The cumulative loss rate and the peak values of ammonium nitrogen and nitrate nitrogen were both significant negative corre- lation with their corresponding soil bulk density, soil porosity, soil organic carbon, CEC and biochar applica- tion amounts. The peak values of nitrate nitrogen had significant positive correlation with soil bulk density. It indicated that biochar could decrease the leaching rate of ammonium and nitrate nitrogen, prolong the mi- gration duration of ammonium nitrogen and nitrate nitrogen in the soils, and decrease the cumulative loss rate of nitrogen in soils.