lo April, 1912.] 



W//eaf and its Cultivalioii. 



203 



TABLE II. 



Amount of Produce. Dry-Matter. Essential and Xon-essential Soil 

 Constituents Removed per Acre from Plot 3 (unmanured). 



Average of 20 Years" Results. 



Careful perusal of the.se tables, representing the averages of 20 years' 

 work, suggests the following remarks : — 



(i) In a 15.2 bushel crop the ratio' of grain to straw is approximately 

 60 : 100 — that is, for every bushel of grain obtained there are 100 lbs. of 

 straw. 



(2) The most important of the essential ash constituents are concen- 

 trated in different portions of the wheat plant, e.g., 70 per cent, of the 

 nitrogen and 75 per cent, of the phosphoric acid is found in the grain, 

 whilst 70 per cent, of the total potash is present in the straw. 



(3) Between 5 per cent, and 6 per cent, of the total dry-matter of wheat 

 is obtained from the soil, whilst no less than 94-95 per cent, is obtained 

 from the atmosphere. 



(4) A T5-bushel crop of wheat removed from the soil 20 lbs. of nitrogen, 

 10 lbs. of phosphoric acid, and 17 lbs. of potash. 



(5) Assuming that the grain is carted oft" the farm and the straw is used 

 for litter and ultimately returned to the soil, the two main constituents taken 

 from the soil are phosphoric acid and nitrogen, whilst the greater part of 

 the potash, together wi!h more than half the organic matter are returned 

 to the soil. 



(6) Assuming, however, that the straw is burnt, as is frequently done 

 in Victoria, and the whole of the grain is sold, then 1.145 lbs. of organic 

 matter of the straw is converted into carbonx acid gas, water, and ammonia, 

 and thus absolutely lost, whilst 77^ lbs. of ash, of which 53 lbs. represent 

 silica, are left behind. 



The loss of organx matter is going on fairlv rapidly in the wheat areas 

 of the State, owing to the continual oxidation of the organic matter of the 



H 2 



