生物炭和氮沉降对落叶松人工林土壤呼吸及其理化性质的影响

Effects of Biochar and Nitrogen Deposition on Soil Respiration and Physical and Chemical Properties of Larix gmelinii Plantation

为了探讨氮沉降下施用生物炭在短期内对土壤呼吸和土壤理化性质的影响,以神农架林区落叶松(Larix gmelinii)人工林为研究对象,设置对照(CK)、添加氮素(处理1)、添加生物炭(处理2)以及添加氮素和生物炭(处理3)共4个处理。2019年5月—9月采用Li-8100A土壤碳通量测量系统测定土壤呼吸速率,9月底采集土壤样品测定理化性质,分析施肥对落叶松人工林土壤呼吸的影响。结果表明:落叶松人工林土壤呼吸速率(R_(s))的变化趋势与土壤温度(T)的变化趋势一致,呈现明显的季节动态。处理1的R_(s)在7月份和8月份均显著高于CK(P<0.05),分别比CK增加189.84%和95.70%;处理2的R_(s)在7月份显著高于CK(P<0.05);处理3的R_(s)在7月份和8月份均显著高于CK(P<0.05)。4种处理的R_(s)与T都呈极显著的指数关系。与CK相比,处理1和处理3的Q_(10)值明显增大,而处理2的Q_(10)值没有明显变化。处理3的土壤有机碳(SOC)和土壤全氮(TN)质量分数均显著高于其他处理(P<0.05),SOC质量分数为52.98 g·kg^(-1),分别比CK、处理1和处理2提高26.48%、22.88%和17.30%;土壤TN质量分数为2.88 g·kg^(-1),分别比CK、处理1和处理2提高13.24%、13.41%和15.99%;处理1、处理2和处理3的土壤全磷(TP)质量分数均显著高于CK(P<0.05),分别比CK提高9.99%、6.92%和8.90%。土壤温度是该地区落叶松人工林生长季土壤呼吸的主要影响因素,模拟氮沉降下添加生物炭有助于该地区土壤碳汇和氮汇的增加。

With Larix gmelinii plantation in Shennongjia forest area,we explored the short-term effects of biochar application under nitrogen deposition on soil respiration and soil physical and chemical properties.The biochar and nitrogen addition experiment including four treatments(control-CK,nitrogen addition-T1,biochar addition-T2,and nitrogen and biochar addition-T3)was conducted in L.gmelinii plantations from May to September 2019 to monitor soil respiration rate by the Li-8100A soil carbon flux measurement system in Shennongjia forest area.At the end of September,the soil samples were collected to determine the physical and chemical properties,and the short-term effects of fertilization on soil respiration in the region were analyzed.The change trend of soil respiration rate(R_(s))in L.gmelinii plantations was consistent with that of soil temperature(T),showing obvious seasonal dynamics.The T1 R_(s) was increased by 189.84%and 95.70%in July and August compared with CK(P<0.05);the T2 R_(s) was significantly higher than that of CK(P<0.05)in July;the T3 R_(s) was significantly higher than that of CK in July and August(P<0.05).The R_(s) and T of the four treatments showed a very significant exponential relationship.Compared with CK,T1 and T3 significantly increased Q_(10)values,while there was no significant result for T2.Soil organic carbon(SOC)of T3 reached 52.98 g·kg^(-1),which was 26.48%,22.88%and 17.30%higher than that of CK,T1 and T2(P<0.05),respectively;soil total nitrogen(TN)of T3 reached 2.88 g·kg^(-1),which was 13.24%,13.41%and 15.99%higher than that of CK,T1 and T2(P<0.05),respectively;soil total phosphorus(TP)of T1,T2 and T3 were significantly higher than that of CK(P<0.05),which was 9.99%,6.92%and 8.90%higher than CK,respectively.Soil temperature is the main influencing factor of soil respiration in the growing season of L.gmelinii plantation in Shennongjia forest area.The addition of biochar under simulated nitrogen deposition can help the increasing of soil carbon sinks and nitrogen sinks in the area.