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]