140


 120


 100


 80


I 60


 40


 20


 0


0 2 4 6 8 10 12 14 16 18


 3000


 2500


 2000


 1500


S1000
5 looo


 500


 0


0 2 4 6


 700-

 600-


 500 -

N^
6 400-

, 300-
0.
 200-


 100

 0*-


0 2 4 6 8 10 12 14 16 18
 Age (years)


Figure 7.10 (Cont.)


8 10 12 14 16 18


0 2 4 6 8 10 12 14 16 18
 Age (years)


On the Left, Available Nutrients on a Mass Basis (mg Nutrient
g"' Soil) and an Areal Basis (g Nutrient m"2 to a Depth of 20
cm, on the Right). Ca (a,b), Mg (c,d), K (e,f), P (g,h) and Fe (i,j).


7-61


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