EndProducts Pathways of Weathering Very slowly weathered minerals

End-Products Pathways of Weathering Very slowly weathered minerals (e. g. , quartz, muscovite) Physical Weathering Continued Disintegration Resistant primary minerals (e. g. , quartz) Slowly weathered minerals (e. g. , feldspars, biotite) Easily weathered minerals (e. g. , augite, hornblende, olivine) Chemical Weathering Iron and aluminum oxide clays Rock Igneous Silicate clays Sedimentary Chemical Weathering Metamorphic Soil solution (K+, Na+, Ca 2+ , Mg 2+, Fe 2+, SO 42 -) Figure 10. 1 Ecological Climatology © 2008 G. Bonan

Relative Rate of Decomposition 8 7 6 5 4 3 2 1 0 5 10 15 20 Temperature 25 30 (o. C) Relative Rate of Decomposition 1. 0 0. 8 0. 6 0. 4 0. 2 0. 0 0 20 40 60 80 100 Soil Moisture (percent of saturation) Figure 10. 2 Ecological Climatology © 2008 G. Bonan

Weight Loss During First Year (%) 80 Dogwood 70 North Carolina 60 Red Maple White Oak 50 Chestnut Oak 40 White Ash 30 Red Maple 20 White Pin Cherry Paper Birch Sugar Maple New Hampshire 10 Beech 0 0 5 10 15 20 25 30 35 40 Lignin: Nitrogen Ratio Figure 10. 3 Ecological Climatology © 2008 G. Bonan

Percent Original Biomass Remaining 100 90 80 70 60 50 Nitrogen Concentration When Net Mineralization Begins 40 0. 5 1. 0 1. 5 2. 0 2. 5 Percent Original Nitrogen Remaining Nitrogen Concentration In Residue (%) Figure 10. 4 150 140 130 120 110 100 90 80 70 60 50 40 Percent Original Biomass Remaining Ecological Climatology © 2008 G. Bonan

Mineralization Metabolic (0. 1 -1 yr) Structural (1 -5 yr) Active (1 -5 yr) Slow (20 -50 yr) Lignin: N Litter Immobilization Passive (200 -1500 yr) Mineralization Figure 10. 5 Ecological Climatology © 2008 G. Bonan

Leaching Organic Matter Clays Oxides Carbonates Soil Layer Litter Humus O Horizon A Horizon E Horizon B Horizon Salts C Horizon Bedrock Figure 10. 6 Ecological Climatology © 2008 G. Bonan

50 Soil Clay Content (%) 45 40 35 30 25 20 15 10 5 0 10 11 12 13 14 15 16 17 18 Annual Mean Temperature ( C) Figure 10. 7 Ecological Climatology © 2008 G. Bonan

Depth To Maximum Clay (cm) 0 20 40 60 80 100 300 400 500 600 700 800 900 1000 Annual Precipitation (mm) Figure 10. 8 Ecological Climatology © 2008 G. Bonan

Organic matter Maximum leaching Clay accumulation Unweathered bedrock 1000 Disintegrated weathered soil material 10 000 100 000 Well-developed Ultisol Time (years) Organic matter Unweathered loess Ca. CO 3, Ca. SO 4 accumulation 2000 4000 6000 Time (years) 8000 Well-developed Mollisol Figure 10. 9 Ecological Climatology © 2008 G. Bonan

et so il organ ic lay er, w Histosols ys se as se rt gr De ry s, d sh ru af ro Pe rm Thick Aridisols bs st Gelisols i , m ist y ldl ci a Wet Entisols B ys cla ry ing ell yd all Sw on as se g in nn gi Be ic Volcan debris Inceptisols as sla nd , d ar ks oil trop ic ds al an ts ores al f opic ubtr Mo Gr Alfisols la dc ys ic cla Ultisols cid gly a n Wet, tropical forest o r t s Coo Fe, Al oxides l, we t, ac con idic ifero us f Spodosols ores t Mollisols Oxisols Vertisols Andisols Extent of weathering and soil development Slight Intermediate Strong Figure 10. 10 Ecological Climatology © 2008 G. Bonan