Journal of Agriculture, Victoria. [lo April, 19 12. 



combustion, the soil contains a limited (|uantity of several essential mineral 

 ingredients which mav onlv be replenished by the application of fertilizers. 



The constituents other than carljon, hydrogen, oxygen and nitrogen are 

 called the inorganic or ash constituents of the plant. 



To properly appreciate the focd requirements of wheat it is necessary 

 to consider the amount of nitrogen and ash constituents removed from the 

 .soil by an average crop. For our purpose, in the absence of sufficient local 

 data, we may consider a summary of the results obtained at Rothamstead 

 where scientific experimental work has been systematically conducted for 

 o\'er seventy years. 



Tables I. and II. are digests of the elaborate tables given in the 

 Rothamstcad Memoirs (Vol. VI.), p. 104. Table I. represents the total 

 produce, dry-matter, ash constituents and nitrogen obtained from plots 2, 

 3, 5 and 10, treated respectively for 20 years with — 



{a) Farmyard manure. 

 (]}) No manure. 

 (c) Mixed mineral manures. 

 {d) Ammonium Salts only. 



TABLE I. 



Quantity per Produce, Dry-Matter, Nitrogen and Ash Constituents 

 Removed per Acre by Wheat Treated with Various Manures. 



(Average of 20 years.) 



No. of Plot. 



Plot 3 — No manure 



Plot 5 — Mixed minerah . . 



Plot 10 — Ammon. salt^ 



Plot 2 — Farmyard manure 



Ash Con- 

 stituents 

 per acre. 



lbs. 

 93-44 

 115-71 

 145- 11 

 246-84 



Nitrogen 

 per acre. 



lbs. 

 20 - 3 

 24-3 

 40 - 

 51-7 



Nitrogen 



and 

 Asli Con- 

 stituents 

 expressed 

 as per cent, 

 of Drv 

 Matter. 



5-72 

 5-92 

 4-96 



5-85 



Balance of 



dry matter 



obtained 



from Air. 



94-28 % 

 94- 08 % 

 95-04 % 

 94- 15 "o 



Of these four plots the unmanured plot (plot 3) approximates more 

 •closely to the average wheat yield of Victoria than do any of the other 

 plots, and may therefore be studied in greater detail. 



Its yield of grain (15-2 bush.) is commonly reached and exceeded in 

 many parts of the State, though the average yield of the State has never 

 •equalled it. 



Table II. has been arranged to show the following details. — (i) total 

 yield; (2) dry-matter; (3) essential soil con.stituents, and (4) non-essential 

 plant constituents removed by the grain and by the straw of a 15.2 

 bush. crop. 



