EFFECT OF SEASON UPON QUALITY 87 



minerals. As was noticed in the case of the wheat crop, 

 nitrate of soda answered better than ammonium-salts in the 

 wet year, giving on Plot 4 A A 45 bushels of grain and 33 '4 cwt. 

 of straw against 41*4 bushels of grain and 26 '8 cwt. of straw on 

 Plot 4 A ; whereas in the dry year the ammonium-salts had a 

 slight advantage. Taking, however, averages over the whole 

 period, it is found that the seasons in which the ammonium- 

 salts give a better crop than the nitrate of soda are wetter 

 throughout than those in which the nitrate of soda is the more 

 effective source of nitrogen. A wet March seems to be the 

 most hurtful to the nitrate of soda plot. The comparative 

 effects of the mineral manures in a wet and dry season are also 

 similar to those noticed in the case of the wheat. In the wet 

 season the crop is very dependent upon supplies of minerals in 

 the manure, and especially on an abundance of phosphoric 

 acid. In 1894 the addition of phosphoric acid raised the 

 yield from 10'4 bushels per acre on Plot 1 A to 34*9 bushels 

 per acre on Plot 2 A, and from 17 '8 bushels per acre on 

 Plot 3 A to 41 - 4 bushels per acre on Plot 4 A. In a dry 

 season it is potash that chiefly tells; for example, in 1893 the 

 addition of potash on Plot 4 A to the superphosphate and 

 ammonium-salts on Plot 2 A produced a specially marked 

 increase of crop, from 181 to 30*8 bushels per acre. 



Doubtless in the wet season the ripening effect of the 

 phosphoric acid is specially valuable, while in a dry season the 

 potash, by inducing a longer period of growth, is more effective 

 in increasing the crop. The ripening action of the phosphoric 

 acid may also be seen in the way it increases the weight per 

 bushel of the grain in a wet season, whereas in a dry season it 

 has little or no effect. 



In the dry season the weight per bushel is much higher 

 than in the wet, and the grain is about equal in weight to the 

 straw, whereas in the wet season the weight of grain only 

 amounts to about 70 per cent, of the straw. 



Taking the results as a whole, it is seen that season has a 

 much greater effect in bringing about changes in the composi- 



