644 Journal of Arjrirnll iir,'. Vicforia. [10 Nov.. 1917. 



Table il. 

 Yield Det Matter per Acre at Various Stages of Growth. 



Table III. 

 Approximate Acre Green Weight of Tubers- 

 Plants PER Acre. 



-Calculating 1'2,000 



1st Harvest 

 2nd Harvest 

 3rd Harvest 

 4th Harvest 



Tons. Cwt. Qrs. Lbs. 



U 4 6 



8 13 2 8 



20 15 3 4 



24 18 3 



Tlie figures in the above tables are of absorbing interest. Apart 

 altogether from the high yield obtained, and this from a soil sho-\ving 

 a low content of total plant food, it will be noticed that the plant does 

 not grow evenly over the full period of growth. 



Computing from the tables it is found that the root growth during 

 the first month is equal to 41 per cent, of the total root development, 

 whilst at the end of the second month this percentage is increased to 9S, 

 meaning that root development practically ceases at the end of two 

 months. 



Comi^uting on the whole plant, approximately 11 per cent, of the 

 total weight produced during the first month is represented by roots. In 

 the second month root development amounts to S-J per cent, of the total 

 production, whilst, during the third month, the root growth amounts to 

 barely ^rd of 1 per cent, of the total plant growth. (Table IV.) 



In the case of the haulm the figures show 22.5 per cent, of the total 

 overhead growth taking place during the first month, and Jt9.S per cent. 

 during the second month — a total of 72.3 per cent, during the first two 

 months, compared with 93 per cent, in the case of root growth previously 

 remarked upon. 



During the third month, whilst, as in the case of the root, growth 

 diminishes, this decrease is not so marked, for the growth of the 

 haulm during this term is 27.7 per cent, of the total overhead weight. 



Compared with the growth of the whole plant over the given periods, 

 the figures show the haulm growth during the first month to equal 8S.5 

 per cent, of the total growth, during the second month this figure falls 

 to li2 per cent., whilst during the third month the growth of the haulm 

 only produced 28 per cent, of the total weight ]iroduced during the 

 month. 



Reviewing the figures given under tubers in Table IV., it is found 

 that less than 1 per cent, of the ultimate yield was formed during the 



