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Formulae Software Home Concepts

 

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

----------_

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

------------------------

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)

------------------------------------

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)

-------------------------------------

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

-------

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 A2 ln A1)

..

t2 t1

(dm2/dm2/day)

 

 

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

..

(ln A2 ln A1)

 

(dm2 days)

 

 

 

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