【摘要】 【目的】研究氮矿化对土壤湿度和温度的响应,为区域土壤供氮潜力评价和预测区域性水热变化对土壤氮素矿化影响提供参考.【方法】采用实验室培养法,研究不同温度（5、15、25、35℃）和水分含量（20%、40%、60%和80%田间持水量（FWC））对华西雨屏区常绿阔叶林表层（0～20 cm）土壤氮素矿化的影响.【结果】温度和水分含量对常绿阔叶林土壤氮矿化影响显著（P<0.05）;相同水分条件下,土壤净氨化速率、净硝化速率和氮净矿化速率均随温度的升高呈先升高后降低的趋势,在25℃时达到最大值;相同温度条件下,土壤净氨化速率、净硝化速率和氮净矿化速率均随水分含量的升高呈先升高后降低的趋势,在60%FWC时达到最大值;在25℃+60%FWC处理下土壤净氨化速率、净硝化速率和氮净矿化速率速率最高,相反,在5℃+20%FWC处理下最低;能获得最大氮净矿化速率的土壤温度和水分含量分别为25.8℃和57.4%FWC;土壤氮净矿化产生的无机氮中铵态氮占54.1%～61.7%;土壤氮矿化Q₁₀值在5～35℃内随温度的升高而降低,氮净矿化在5～15℃内对温度敏感性最高.【结论】适宜的土壤水分含量和温度是促进常绿阔叶林土壤氮矿化的关键,研究区气温变暖在一定程度上能促进氮矿化和提高土壤供氮潜力,而研究区多雨则增加了土壤氮淋失的风险.更多还原

【Abstract】 【Objective】 To clarify the response of nitrogen mineralization to soil moisture and temperature in order to provide a scientific basis for the evaluation on regional soil nitrogen supply potential,and prediction of the impacts of regional hydrothermal changes on soil nitrogen mineralization.【Method】 A laboratory incubation experiment was conducted to study the effects of different temperatures（5,15,25 and 35 ℃） and moistures（20%,40%,60% and 80% field water capacity,FWC） on soil nitrogen mineralization（0 to 20 cm） of the evergreen broad-leaved forest in rainy area of western China.【Result】 Soil temperature and moisture significantly affected the soil nitrogen mineralization（P<0.05）.Under same moisture condition,soil net ammonification rate,net nitrification rate and net nitrogen mineralization rate increased with the increase of temperature and reached the maximum under 25 ℃ treatment,and then decreased with the increase of temperature.Under same temperature,the soil net ammonification rate,net nitrification rate and net nitrogen mineralization rate increased with the increase of moisture and reached the maximum under 60% FWC treatment,and then decreased with increase of moisture.In all treatments,the soil net ammonification rate,net nitrification rate and net nitrogen mineralization rate were highest under 25 ℃ and 60% FWC treatment;and they reached the minimum under 5℃ and 20% FWC treatment.The optimal temperature and moisture of soil net nitrogen mineralization were 25.8 ℃ and 57.4% FWC.Ammonium accounted for 54.1% to 61.7% of inorganic nitrogen derived from net N mineralization.Q₁₀ decreased with the increase of temperature in range of 5 to 35℃.Net nitrogen mineralization was most sensitive at 5 to 15 ℃.【Conclusion】 Appropriate soil temperature and moisture are important for promoting nitrogen mineralization rate of the evergreen broad-leaved forest.To some extent,the climate warming can promote nitrogen mineralization and enhance soil nitrogen supply potential,but rainfall increases the risk of soil nitrogen leaching in research area.更多还原