磷添加对南亚热带森林土壤有机碳氮矿化影响的培养实验研究

Effects of P Addition on Organic C and N Mineralization from Subtropical Forests Soil during Incubation,Southern China

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.