90 EXPERIMENTS UPON BARLEY 



to raise the crop above, nor even up to the level of the wholly 

 unmanured Plot 1. 



The weight per bushel increases with each addition of 

 nitrogen ; up to a certain point the proportion of grain to straw, 

 and the weight of 1000 grains also increases, but on Plot 5, 

 with the highest nitrogen, these characters begin to show a 

 decline. The percentage of nitrogen in the barleys increases 

 with the supply in the soil, but only becomes at all above the 

 average with the highest sample from Plot 5. The valuation 

 rises with the supply of nitrogen in the soil up to a certain 

 point, but shows a slight decline for the last sample from 

 Plot 5. 



Summarising these results, we see that a good weight per 

 bushel and a large berry cannot be obtained without a 

 sufficient supply of nitrogen in the soil, but when a certain 

 point has been reached further excess of nitrogen in the soil 

 results in coarseness and an excessive proportion of nitrogen 

 in the grain, deteriorating the quality. A fair supply of 

 phosphates are also necessary to ensure early and complete 

 maturation. In the Agdell field, Plot 4 represents the best 

 soil conditions to obtain high quality in the barley ; on Plot 5 

 this optimum point has been passed, and the land has become 

 too rich in nitrogen compounds. 



The barley grown in rotation is on the whole much superior 

 to that grown continuously, mainly because its supply of 

 nitrogen is derived from the nitrification of nitrogenous residues 

 in the soil, i.e., from what a farmer would call "condition," and 

 not from nitrogenous manure directly applied. 



Practical Conclusions 



1. The barley crop is far more dependent than wheat upon 

 a supply of manure, and will require manuring when it is 

 grown as a second white-straw crop, except on land in very 

 good condition. After roots which have been wholly or 

 partially fed on the land, or after a clover ley, there is already 

 sufficient, and often too much, nitrogenous matter in the land. 



