采用室内培养的方法,分析了磷添加对南亚热带鼎湖山马尾松林(PMF)、针阔叶混交林(PBMF)和季风常绿阔叶林(MEBF)土壤(0~10cm)CO小CH4排放/吸收和有机氮矿化的影响。结果表明:28周的培养,100mg磷添加处理土壤C—CO2累积排放量依次为PMF、PBMF和MEBF对照的82.4%、84.4%和102.8%,2000mg磷处理土壤依次为其对照的107.2%、101.2%和109.1%;100mg磷处理土壤CH4累积排放量依次为其对照的69.9%、102.7%和66.3%,2000mg磷处理土壤依次为其对照的-57.4%、25.3%和22.4%,其中,磷在处理初期较一致的提高土壤CO2和CH4排放,磷对土壤有机碳矿化的影响与森林的土壤状况有关,添加的磷浓度越高,其促进作用越强。1周的培养,100mg磷处理土壤有效氮净矿化量依次比PMF、PBMF和MEBF对照少37.06%、39.60%和28.62%,2000mg磷处理土壤依次比其对照少70.97%、84.14%和187.97%,100mg磷处理土壤硝态氮净矿化量依次比其对照少48.06%、40.45%和28.03%,2000mg磷处理土壤依次比其对照少254.09%、115.32%和238.50%,磷显著的抑制土壤有机氮的矿化和硝化。结果建议,在研究P对土壤有机碳氮矿化过程时应充分考虑土壤对P的吸附作用。
The effect of P addition on organic C and N mineralization in soils (0 - 10 cm) from three forest types, pine (Pinus massoniana) forest (PMF), pine and broad-leaved mixed forest (PBMF) and monsoon evergreen broad-leaved forest (MEBF) , in Dinghushan, southern China, was studied based on indoor ineubaiton. Soils were incubated at 25 ℃ for 28 wk or 1 wk. The results showed that the total C-CO2 cumulative amount in the 28 wk incubation from PMF, PBMF and MEBF soil treated with 100 mg P was 82.4%, 84.4% and 102.8% of that from their control, respectively, and the amount treated with 2 000 mg P was 107.2%, 101.2% 和 109.1% of that from their control, respectively; The CH4 cumulative amount from PMF, PBMF and MEBF soil treated with100 mg P was 69.9%, 102.7% and 66.3% of that from their control, respectively, and the amount treated with 2 000 mg P was -57.4%, 25.3% and 22.4% of that from their control, respectively. The addition of P led to a short-term increase in CO2 and CH4 emission after P application, and the responses of C-CO2 and CH4 evolution to P addition related to the added P concentration and forest types. The addition of P inhibited significantly organic N mineralization and N nitrification. The available N net production in the 1 wk incubation from PMF, PBMF and MEBF soil treated withl00 mg P was less 37.06%, 39.60% and 28.62% than that from their control, respectively, the production treated with 2000 mg P was less 70.97%, 84.14% and 187.97% than that from their control, respective- ly; The nitrate net production from PMF, PBMF and MEBF soil treated withl00 mg P was less 48.06% , 40.45% and 28.03% than that from their control, respectively, the production treated with 2 000 mg P was less 254.09%, 115.32% and 238.50% than that from their control, respectively. We suggested that the sorption of P to soil minerals must to be taken into account in the future research.