《森林生态学》课程教学资源（专题讲座）Forest Management and Nutrient Cycling（2/2）Determination of nutrient balances

Universitat fur Bodenkultur Wien University of Natural Resources and Life Sciences Vienna Department of Forest-and Soil Sciences Forest management and nutrient cycling ll Determination of nutrient balances Klaus Katzensteiner Institute of Forest Ecology,BOKU Vienna October 28-29,2013,College of Forestry,Northwest A&F University,Yangling,China 出

Forest management and nutrient cycling II Determina4on of nutrient balances Klaus Katzensteiner Ins.tute of Forest Ecology, BOKU Vienna October 28-29, 2013, College of Forestry, Northwest A&F University, Yangling, China Universität für Bodenkultur Wien University of Natural Resources and Life Sciences Vienna Department of Forest- and Soil Sciences

Terrestrial ecosystems at the interface between spheres Inner cycle Atmosphere Outer cycle Biogeochemical cycle Biosphere Pedosphere Hydrosphere Geosphere Lithosphere

Terrestrial ecosystems at the interface between spheres Atmosphere Hydrosphere Lithosphere Biosphere Pedosphere Geosphere Inner cycle Outer cycle Biogeochemical cycle

A simple system approach:ecosystem as an open system>matter and energy exchange at the interface to neighboring systems Input Input Vegetation The system agueyp Stock change may be divided into subsystems Soil Output Output Mass-and enegy flows connect system elements and the system with the environment

A simple system approach: ecosystem as an open system à maMer and energy exchange at the interface to neighboring systems Input Output Stock change Input Output Vegeta.on Soil Stock change The system may be divided into subsystems ... Mass- and enegy flows connect system elements and the system with the environment

Nutrient accounting in Forest ecosystems: Account balance over time t:B(t)=lin*At-lout*At I...Flux rate B(t)=0→steady state B(t)≠O:→stock change

Nutrient accoun4ng in Forest ecosystems: Account balance over .me t: B(t) = Iin *Δt- Iout *Δt I … Flux rate B(t) = 0 à steady state B(t) ≠ 0: à stock change

Nutrient balance models- a management tool? △nutrient stock(N) input from the atmosphere(deposition) +biological fixation fertilization losses with seepage - denitrification losses with harvest

Nutrient balance models – a management tool? Δ nutrient stock (N) = input from the atmosphere (deposi4on) +biological fixa4on + fer4liza4on - losses with seepage - denitrifica4on - losses with harvest

Nutrient balance models- a management tool? A nutrient stock (e.g.P,K,Ca,Mg) ◇ input from the atmosphere input from mineral weathering fertilization losses with seepage losses with harvest

Nutrient balance models – a management tool? Δ nutrient stock (e.g. P, K, Ca, Mg) = input from the atmosphere + input from mineral weathering + fer4liza4on - losses with seepage - losses with harvest

Nutrient cycles in forest e cosyste ms Atmospheric inputs Tra nsloc a tion l一Foliar uptake Foliage Foliar Leaching Fertilization,Recycling Ltter Fa / Forest Floor Harvest Root up缸ke Hum us Mine ra za tio n Litter Leaching Mine raliza tion Soil We athering Soil Unavaila ble Ava ilable Pools Pools Im mobilzation Adsorp tion Soil Le aching Output

Atmospheric inputs Output FoliageWo o d Fore st Floor Soil Availa ble Pools Soil Unavaila ble Pools Tra nsloc a tion Foliar Lea ching Litter Fall Foliar uptake Root up ta ke Hum us Mine ra liza tion Litter Leac hing Mine ralization We athering Im mobilization Adsorp tion Nutrient c yc les in forest ec osystems Soil Le ac hing Harvest Fer4liza4on, Recycling

Requirement for steady state conditions compensation demand 八 -input from the atmosphere input from mineral weathering losses with seepage losses with harvest

Requirement for steady state condi.ons compensa4on demand = - input from the atmosphere - input from mineral weathering + + losses with seepage + losses with harvest

How to determine nutrient balances? A.Replicated measurement of stock>Calculation of stock changes B.Replacement of time with space ,false time series'(chronosequences) C.Direct measurements of inputs and outputs to and from the system D.Models:require knowledge of processes and thorough testing(against A,B or C)

How to determine nutrient balances? A. Replicated measurement of stock à Calcula.on of stock changes B. Replacement of .me with space à ‚false .me series‘ (chronosequences) C. Direct measurements of inputs and outputs to and from the system D. Models: require knowledge of processes and thorough tes.ng (against A, B or C)

Determination of nutrient stocks in ecosystems- The biomass compartment Harvest Drying Weighing Nutrient analyses >Mass [g]nutrient concentration [g.g1] Biomasse nutrient stock [g] Woody debris &forest floor Mineral soil Bedrock

Woody debris &forest floor Mineral soil Biomasse Bedrock Determina.on of nutrient stocks in ecosystems – The biomass compartment Harvest Drying Weighing Nutrient analyses àMass [g] * nutrient concentra.on [g.g-1] = nutrient stock [g]