4 
The Pei'maneni WJieai and Barley ^Jxperlmenis 
dressed grain is low, and this will generally be found to be the 
case wherever wheat is grown continuously on the same soil. 
In all of the experiments where nitrate of soda was used, the 
amount of straw is greater than where salts of ammonia were 
used. 
Turning now to the barley, although the influence of season 
is still considerable, it will be seen that the fluctuations due to 
this cause are very much less than in the case of the wheat. 
This is the result of the barley being sown in the spring, and 
thus escaping the vicissitudes of the winter months. Further, 
the climate of Great Britain is far more suitable for the growth 
of barley than that of wheat, and to this may be added that the 
soil of Stackyard Field is in its texture far more suitable for the 
growth of barley. For all these reasons it might be expected 
that the crops of barley, both the manured and the unmanured, 
would be superior to those of the wheat. From some cause, 
possibly some slight difierence in the texture of the soil, the two 
unmanured plots differ considerably, one yielding close upon 27 
bushels per acre and the other 23 bushels. As the plot which 
received the mixed mineral manures only gave 23 bushels per 
acre, it is probable that this produce more nearly represents the 
yield of the unmanured plot than the other. As in the case of 
the wheat, the mineral manure alone produces no increase in the 
yield of the crop. While, however, the addition of salts of 
ammonia and nitrate of soda added only 7 bushels to the 
produce of the wheat, these salts have added 16 and 17 bushels 
respectively to the barley crop. This large increase in barley 
over wheat by means of ammonia and nitrate alone is doubtless 
due to the difference in the character of the roots of the two 
plants. Wheat requires a solid bed, and its roots descend deep 
into the subsoil, while the barley requires a fine tilth, and its 
roots take much of the food near the surface. 
It is the surface soil in Stackyard Field which contains a 
large amount of fertility. While, therefore, the application of 
ammonia or nitrate to the unmanured plots increases the crop 
by IG to 17 bushels, the addition of minerals has only added 
to it, in one case 3^ bushels, and in the other case G bushels. 
Doubling the salts of ammonia adds 7 bushels to the crop, pro- 
ducing 51 bushels, while doubling the nitrate of soda also adds 
7 bushels to the crop, producing 53-3 bushels per acre. In all 
these instances nitrate of soda has given a greater increase in 
the grain and straw of the barley crop than the salts of 
ammonia, whereas in the wheat the nitrate always gave the 
largest increase in the straw, but not so in the grain. A 
general examination of the wheat and barley experiments shows 
a remarkable agreement in the results, and, when they appear to 
