生物质炭添加对不同pH紫色土硝化作用及N2O排放的影响

Effects of Biochar Application on Nitrification and N2O Emission in Purple Soils with Different pH

生物质炭施用可能对土壤中氮素硝化过程和N2O排放产生影响。本研究通过室内培养试验,研究铵态氮肥与玉米秸秆生物质炭施用量(0、1%、2%、5%、10%,m/m)对酸性(pH 5.10)和石灰性(pH 8.15)紫色土氮素硝化率、净硝化速率及N2O排放特征的影响。结果表明:①酸性和石灰性紫色土生物质炭处理平均净硝化速率相比对照分别降低了33.7%~93.7%和7.5%~40.9%,生物质炭添加抑制了酸性和石灰性紫色土硝化作用,在酸性紫色土中生物质炭对硝化作用的抑制作用随施用量的增加而增强,在石灰性紫色土中无明显规律。②与对照相比,酸性紫色土N2O累计排放量在1%生物质炭和2%生物质炭处理下降幅分别为15.9%和27.7%,在5%和10%生物质炭处理下增幅分别为60.1%和93.2%;石灰性紫色土生物质炭各处理N2O累积排放量均显著高于对照。③综合考虑,在酸性紫色土中1%、2%生物质炭施用对硝化作用抑制和N2O减排综合效果最好,但在石灰性紫色土中无明显抑制和减排效果。

Biochar can influence soil nitrogen nitrification and N2O emission.An indoor incubation experiment was conducted to study the net nitrogen nitrification rates and N2O emission in acidic(pH 5.10)and calcareous(pH 8.15)upland purple soils under different application rates of maize straw biochar(0,1%,2%,5%,and 10%dry soil weight)with ammonium nitrogen fertilizer.The results showed that:1)Biochar addition inhibited net nitrogen nitrification rate in purple soils,compared with the control treatment(no biochar application),biochar application reduced the average net nitrogen nitrification rate by 33.7%-93.7%in acidic purple soil and 7.5%-40.9%in calcareous purple soil.With the increase of biochar application rate,the inhibition was enhanced in acidic purple soil but irregular in calcareous purple soil.2)compared with the control treatment,cumulative N2O emission in acidic purple soil decreased by 15.9%and 27.7%with 1%and 2%biochar addition rates,increased by 60.1%and 93.2%with 5%and 10%biochar addition rates,respectively,and cumulative N2O emission of all biochar addition treatments in calcareous purple soil were significantly higher than that of the control treatment.3)In general,biochar has no positive effect for calcareous purple soil in inhibiting nitrification and mitigate N2O emission,while 1%and 2%biochar addition rates are optimal for in acidic purple soil.