吉林西部盐碱农田有机碳矿化和激发效应对氮磷添加的响应

为了研究不同盐碱程度旱田和水田土壤有机碳（SOC）矿化对氮、磷添加的响应，定量化其激发效应的大小和方向，选择了吉林西部3块盐碱旱田样地（H1，H2，H3）和3块盐碱水田样地（S1，S2，S3），采用实验室模拟培养，将无机营养素（（NH₄）₂SO₄、KNO₃和KH₂PO₄）以7种形式添加到0~15 cm表层土壤样本中，在25 ℃恒温箱内连续监测32 d的CO₂释放量，分析7种氮、磷添加处理对SOC矿化和激发效应的影响。结果表明：1）按7种处理形式分别添加200 mg/kg和1 000 mg/kg氮或磷，SOC矿化量和矿化速率均增加了158.5%~876.5%；同一添加物的质量分数越高，SOC矿化量越大，且随着培养时间延长，SOC矿化速率呈逐渐降低的趋势。2）在培养期间，各添加组均产生了正激发效应。3）在培养期间，部分处理组的SOC矿化、激发效应和碱化度表现出显著负相关性（显著性水平p<0.05）。碱化度越大，SOC矿化作用和激发效应越弱；矿化作用越大，正激发效应越低。4）与水田土壤相比，旱田SOC矿化和激发效应对添加氮、磷的响应更大。

Response of Organic Carbon Mineralization and Priming Effect to Nitrogen and Phosphorus Addition in Saline-Alkali Farmland in Western Jilin Province

In order to study the response of soil organic carbon (SOC) mineralization of upland and paddy soils with different salinity to the addition of nitrogen and phosphorus, and to quantify the magnitude and direction of its priming effect, three saline-alkali upland sample plots (H1, H2, H3) and three saline-alkali paddy sample plots (S1, S2, S3) in western Jilin were selected and simulated in the laboratory. The inorganic nutrients ((NH₄)₂SO₄, KNO₃,and KH₂PO₄) were added to the 0-15 cm soil samples in seven forms. The CO₂ emission was continuously monitored for 32 d in a 25℃ incubator, and the effects of seven nitrogen and phosphorus treatments on SOC mineralization and priming were analyzed. The results showed:1) The addition of 200 mg/kg and 1 000 mg/kg nitrogen or phosphorus significantly increased the SOC mineralization accumulation and the SOC mineralization rate by 158.5%-876.5%. The higher the concentration of the same additive, the greater the SOC mineralization accumulation; With the extension of the incubation time, the SOC mineralization rate decreased gradually. 2) During the period of incubation, a positive priming effect was produced in each group. 3) During the incubation period, the SOC mineralization, priming effect, and alkalinity of some treatment groups showed significant negative correlation (p<0.05). The higher the alkalinity, the weaker the SOC mineralization and priming effect; The greater the mineralization, the lower the positive priming effect. 4) Compared with paddy soil, the response of SOC mineralization and priming effect to the nitrogen and phosphorus addition was larger in upland soil.