Formulae

1. Crop growth rate (CGR)    =           W2 - W1

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t2 - t1

Unit = g m-2 land surface day-1

Also CGR = NAR x LAI

2.      Relative growth rate (RGR)  =             log e W2 – log e W1

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t2 - t1

Unit =   g  kg-1 day-1

(Typical values = 10-400 g  kg-1 day-1)

3. Net Assimilation Rate (RGR) =                W2 – W1   (log e A2 – log e A1)

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A2 - A1     (t2 – t1)

Unit =   g  m-2 day-1

(Typical values = 1-30 g  m-2 day-1)

4. Leaf Area Ratio (LAR)    =                    A2 - A1     (log e W2 – log e W1)

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W2 - W1   (log e A2 – log e A1)

Unit =    m2  kg-1

(Typical values = 10-60  m2  kg-1)

Also  LAR = LWR x SLA

5. Leaf Weight Ratio (LWR)              =       Lw

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W

6. Specific Leaf area (SLA)    =                   A

-------

Lw

Unit =    m2  kg-1

(Typical values = 5-30   m2  kg-1)

cm2 g-1 = 0.1 m2 kg-1

6. Specific Leaf weight (SLW)    =             Lw

-------

A

Unit =      kg-1    m2

(Typical values = 0.033-0.200    kg-1 m2)

7. Relative leaf area growth rate =    (ln A2ln A1)

………………..

t2 – t1

(dm2/dm2/day)

8. Leaf area duration (LAD) =    (A2-A1) (t2- t1)

………………..

(ln A2ln A1)

(dm2 days)

Where Lw is the leaf weight, W = total dry wt, A = leaf area, t = time