50 



The Rothamsted Wheat Experiments. 



Although the ingredients furnished to the two plots differ 

 widely, the average produce is nevertheless almost the same 

 on each, as is clearly shown in Table X. 



TABLE X. FARMYARD MANURE (Plot 2) AND ARTIFICIAL MANURE 

 (Plot 7) COMPARED. 



Taking the whole thirty-two years, the difference in the 

 average produce per acre per annum is seen to be less than 

 one bushel of grain in fact, only three-quarters of a bushel. 

 Of total produce, grain and straw, the mixed minerals and 

 ammonia-salts on plot 7 gave an increase over the farmyard 

 manure on plot 2, over the same period, of 1561b. per acre 

 per annum. The most striking contrast between these two 

 manures, which furnish almost identical results, is that whilst 

 the farmyard manure supplies to the soil a large amount of 

 organic matter, the artificial manure supplies none. Each 

 year plot 2 received in the farmyard manure about 85401b. 

 of organic matter, whilst the crop grown upon it would not 

 contain more than one-half this quantity. Yet the artificial 

 manures on plot 7, supplying no organic matter whatever, 

 produced a crop which contained rather the larger amount of 

 organic matter of the two ; and it can be shown that, by 

 merely increasing the amount of nitrogen, a still larger 

 amount of organic matter can be obtained in the crop. Thus 

 plot 8, receiving 1291b. of nitrogen per annum (still much 

 less than that supplied in the farmyard manure) gave, over 



