AVEKAGE PKODUCE OF PLOTS 



35 



phosphate contains 37 per cent, phosphate made soluble, or 66 Ib. of soluble 

 phosphoric acid. 



On Plots 9, 15, 16, and 19 certain changes in the manuring have been 

 made during the progress of the experiments, which are set out in detail in 

 the "Memoranda" for 1901. 



Table XV. shows the average production of grain and 

 straw for the whole period of sixty-one years, for the last ten 

 years, and for the single year 1911. 



TABLE XV. Experiments on Wheat, Broadbalk Field. Produce of Grain 

 and Straw per acre. Average over 61 years (1852-1912) ; and over 10 

 years (1903-1912); also Produce in 1911. 



Produce by Minerals. 



t Produce by Ammonium-salts. 



The grain is expressed in measured bushels per acre, the 

 weight of the bushel depending on the .plot and season. The 

 straw, which includes chaff, etc., is given in cwt. per acre. 



Table XVI. shows the average production of certain of the 

 plots for the six successive ten-year periods from 1852 to 1911. 

 Although ten-year periods are not long enough entirely to 

 remove the effect of season, yet the table enables one to judge 

 whether the fertility of the plots has increased or diminished 

 under the treatment they receive. 



