氮肥配施纳米碳对植烟土壤氮素转化及N_(2)O排放的影响

Effects of Nano-carbon on Nitrogen Transformation and N_(2)O Emissions from Tobacco Planting Soils

采用实验室静态培养方法,通过氮肥配施不同量纳米碳来探究纳米碳对植烟土壤氮素转化以及N_(2)O排放的影响。试验在等氮条件下共设置5个处理:CK,硝酸铵(N 200 mg/kg,下同);NC1,硝酸铵+纳米碳(2.5 g/kg);NC2,硝酸铵+纳米碳(5 g/kg);NC3,硝酸铵+纳米碳(10 g/kg);NC4,硝酸铵+纳米碳(15 g/kg)。结果表明:NC3和NC4处理较CK处理显著降低了土壤pH(P<0.05);与CK处理相比,NC1、NC2、NC3和NC4处理在培养前期增加了土壤NH4^(+)-N含量,相应降低了NO–_(3-)N含量;在培养结束时,与CK处理相比,添加纳米碳处理显著降低了无机氮含量,而显著增加了CO_(2)累积排放量(P<0.05);另外,添加纳米碳处理较CK处理增加了N_(2)O累积排放量,但仅NC4处理与CK处理间差异显著(P<0.05),N_(2)O累积排放量与CO_(2)累积排放量呈显著正相关关系(R2=0.50,P<0.001)。可见,添加纳米碳能够降低土壤pH和无机氮含量,抑制土壤硝化作用,同时还可以提高微生物活性和增加N_(2)O排放量。

A laboratory static culture was conducted in order to better understand the effects of different amounts of nano-carbon on nitrogen transformation and N_(2)O emission of tobacco-plating soil.The experiment included five treatments on equivalent N basis:CK,ammonium nitrate(N 200 mg/kg);NC1,ammonium nitrate+nano-carbon(2.5 g/kg);NC2,ammonium nitrate+nano-carbon(5 g/kg);NC3,ammonium nitrate+nano-carbon(10 g/kg);NC4,ammonium nitrate+nano-carbon(15 g/kg).The results showed that NC3 and NC4 treatments significantly decreased soil pH value compared with CK(P<0.05).Compared with CK,treatments amended with nano-carbon increased the concentrations of NH4^(+)-N in the early period of incubation and decreased the concentrations of NO–3-N accordingly.At the end of the incubation,treatments amended with nano-carbon significantly decreased the concentrations of inorganic nitrogen compared to CK(P<0.05).Addition of nano-carbon treatment significantly increased the cumulative CO_(2)emissions compared to CK(P<0.05).Compared with CK,NC4 treatment significantly increased the cumulative N_(2)O emissions(P<0.05).In addition,there was a significant positive correlation between cumulative N_(2)O emissions and cumulative CO_(2)emissions(R2=0.60,P<0.001).The above results indicate that the addition of nano-carbon can decrease soil pH value and the concentrations of inorganic nitrogen,inhibit soil nitrification,improve microbial activity and increase N_(2)O emissions.