国际森林土壤研讨会课件2015-10-26 Fuzhou Biao Zhu宣讲培训.pptxVIP

Rhizosphere priming effects in response to soil temperature and moisture dynamics;Outline;Rhizosphere priming effect (RPE);RPE is important for SOM decomposition;Outline;RPE led to higher Q10 of SOM decomposition;Outline;No-plant control, constant moisture (25%) Sunflower, constant moisture (25%) Sunflower, severe drying-wetting (8-25%) Soybean, constant moisture (25%) Soybean, moderate drying-wetting (16-25%) ;The intensity of drying-wetting affects RPE;Drying-wetting affect RPE through root biomass?;Outline;RaMPs facility at Konza prairie LTER, Kansas Control – Ambient rainfall Warming – Ambient rainfall Control – Delayed rainfall Warming – Delayed rainfall Warming: +2oC at 15 cm depth Delayed rainfall: increase dry intervals by 50% without changing total amount of rainfall C3 grass (Bromus inermis) in C4 soil 1 m x 1m plot, 4 replicates, seeded in June 2009, measured in 2010 (May, July, September) Buried PVC collar (40-cm deep): no-plant Closed-circulation 24-hour trapping by 4M NaOH solution ;Warming and altered rainfall effects vary with season;Soil-derived CO2 (RH) is altered by living roots;Rhizosphere priming effect;Rhizosphere priming effect and plant biomass;Outline;Annual grasses (Avena), Mollisol, Hopland CA 13C-labeled roots (Avena, 5.5 atom% 13C) added to two depths (8-12 and 38-42 cm) Fate of 13C in CO2, DOC, SOC (bulk and fractions);Soil temp. (unplanted = control heated 4±0.2 oC);Soil moisture (unplanted control warming);Soil moisture (unplanted ambient warming);Root litter – derived 13CO2 (wet vs. dry season);Summary ;1-2 PhDs and 1-2 Postdocs are available in my lab in 2016 Department of Ecology, Peking University biaozhu@pku.edu.cn ;Thank you for your attention!;Trapping CO2 in 0.5 M NaOH solution for 48 hours;Mechanisms of RPE