施用生物质炭对旱地红壤有机碳矿化及碳库的影响

为探究生物质炭施入旱地红壤后对该地区土壤有机碳矿化以及有机碳库的影响,采用田间定位试验,设置7种生物质炭施用量处理,分别为0(C0),2.5(C1),5(C2),10(C3),20(C4),30(C5),40t/hm2(C6),以三库一级动力学理论为基础,对这7种处理的土样进行了室内呼吸培养试验。结果表明:(1)与C0相比,C4、C5和C6处理的土壤有机碳含量呈上升趋势,C5处理土壤有机碳含量上升幅度最大为14.66%;C2、C3、C4、C5和C6处理土壤活性碳均显著增加,C6处理增幅最大为25.00%;土壤惰性碳在C3、C4、C5和C6处理中显著增加,增幅分别为18.92%,40.09%,53.60%和49.55%;除C5处理外,其他生物质炭施用量下土壤缓性碳相对于C0处理,分别降低了1.96%,6.54%,8.82%,9.31%和12.91%。(2)与C0处理相比,施加生物质炭后土壤有机碳累积矿化量均显著降低,C6处理降低幅度达25.93%。随着生物质炭施用量的增加,土壤有机碳累积矿化量逐渐降低。(3)土壤有机碳、活性碳和惰性碳与生物质炭施用量存在极显著(p0.01)的正相关,土壤缓性碳与其存在显著(p0.05)的负相关。研究结果可为提升典型旱地红壤肥力,减缓温室气体排放提供科学依据。

Effects of Biochar on Soil Organic Carbon Mineralization and Carbon Pool in Upland Red Soil

In order to study the effects of biochar addition on soil organic carbon (SOC) mineralization and carbon pool in upland red soil,a field experiment was conducted to amend the soil with biochar at different rates,i.e.0 t/hm2 (C0),2.5 t/hm2 (C1),5 t/hm2 (C2),10 t/hm2 (C3),20 t/hm2 (C4),30 t/hm2 (C5) and 40 t/hm2 (C6).The components of soil organic carbon (SOC) and cumulative carbon mineralization were measured on the basis of the three pool theory of SOC,in combination with a laboratory soil incubation experiment.The results showed that:(1) The SOC content was higher in the C4,C5,and C6 treatments than in the C0 treatment,with the C5 treatment significantly increasing SOC content by 14.66 ％.Compared with the C0 treatment,the C2,C3,C4,C5,and C6 treatments increased active SOC content significantly.The increase rate of active SOC content in the C6 treatment (25.00％) was the highest.The C3,C4,C5,and C6 treatments significantly increased the inert SOC contents,i.e.by 18.92％,40.09％,53.60％ and 49.55％,respectively,compared with the C0 treatment.The inert SOC content in the C1,C2,C3,C4 and C6 treatments were significantly decreased,i.e.by 1.96％,6.54％,8.82％,9.31％ and 12.91％,respectively,compared with the C0 treatment.(2) The SOC cumulative mineralization rate was lower in the biochar addition treatments than in the C0 treatment,being reduced by 25.93％ in the C6 treatment.Furthermore,the SOC cumulative mineralization decreased as the biochar application rate was increased.(3) The contents of SOC,active SOC,and inert SOC were significantly positively correlated with biochar application rate.There was a significant negative correlation between slow SOC content and biochar application rate.This study can provide a scientific basis for improving soil fertility and reducing the emission of greenhouse gas in upland red soil.