Estimation of maximum dry weight of total plant weight at harvest (t/ha) from maximum fresh weight of marketable yield.

 

If the total dry weight yield is represented Wtotal then

 

Wtotal = Wmkt × Pdm × 100/ Hi

 

where

 

Wmkt = marketable fresh weight in t/ha

Hi       = harvest index = marketable / total plant fresh weight (0 ~ 1)

Pdm    = Percentage dry matter total plant fresh weight (0 ~ 100)

 

Wmkt and Hi are user derived information.  To facilitate conversion of Wmkt to the required units from some other units the following conversion factors are given below.  Measured values of Pdm are also given below.

 

Measured values of percent dry matter at commercial maturity of crops grown in  central England with near optimum levels of nutrients­­­­­­

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Residue

% dry matter of entire plant (Pdm)

Cabbage (summer)

8.2

Cabbage (winter)

11.0

Carrot

12.6

Broad bean

16.0

French bean

14.5

Leek

19.7

Lettuce

7.8

Pea

23.9

Radish

9.7

Red beet

14.5

Spinach

11.1

Sugar beet

20.4

Swede

11.8

Turnip (white)

9.8

Wheat (spring) 

88.6

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Data derived from Journal of Agricultural Science, Cambridge, (1980) 95, 441-485

 

 

Conversion factors

1 UK ton/acre = 2.5107 t/ha                            1 UK ton         = 1.0161 t

1 t                    =  1000 kg                               1 lb                  =   0.4536 kg

1 acre               =   0.4047 ha