28 IMPROVING THE QUALITY OF WHEAT. 



It is evident that in all experiments with depleted soils the plants on 

 the plots receiving complete fertilizers would take up larger amounts 

 of plant food, including nitrogen, than would plants on immanured 

 soils. Any conditions that would prevent the normal ripening of the 

 crop on both soils would therefore leave a higher percentage of nitro- 

 gen in the plants upon the unmanured soil. On the other hand, 

 under conditions which would permit of a complete maturation of the 

 crop there might be no difference in the composition of the grain from 

 the manured and unmanured soils. It is evident, however, that the 

 production of both nitrogen and starch in pounds per acre would be 

 greater on the manured soils. 



Another condition that may affect the results is the arrested devel- 

 opment- of kernels on unmanured soils that are seriously depleted of 

 plant food. Such depletion may interfere with complete maturation 

 of the crop while the crop on the manured soil will mature fully. In 

 consequence the grain on the unmanured soil will contain a higher 

 percentage of nitrogen but a smaller yield per acre. The use of a 

 nitrogenous manure alone on exhausted soils may likewise result in 

 a grain of higher nitrogen content. 



Expressed in a more general way, this means that wheat of the 

 same variety grown under the same climatic conditions will have 

 approximately the same percentage of nitrogen if allowed to mature 

 fully, but any permanent interruption in the process of maturation 

 will result in a higher percentage of nitrogen, and in the latter case the 

 percentage of nitrogen will depend upon the stage at which develop- 

 ment was interrupted, and also upon the amount of nitrogen accumu- 

 lated by the plant, that being greater on soils manured with nitroge- 

 nous fertilizers alone than on exhausted soils, and greater on soils 

 receiving complete manures than on exhausted soils receiving only 

 nitrogenous fertilizers, provided the stage at which development 

 ceased be the same in both cases. It thus happens that wheat grow- 

 ing on the soil allowing it to absorb the largest amount of nitrogen 

 will, other things being equal, have a higher nitrogen content if the 

 development of the kernel be permanently checked, although if it 

 were allowed to mature fully it would not have a greater percentage 

 of nitrogen than that grown on the soil affording less nitrogen. 



Reviewing the experiments, w r e find that in Lawes and Gilbert's 

 first experiment the percentage of nitrogen in the unmanured soil was 

 less than on the soil receiving only nitrogenous fertilizer, and that the 

 weight of grain per bushel and the percentage of good kernels on the 

 two plots were practically the same. It would not appear, therefore, 

 that the wheat on the plot receiving the nitrogenous fertilizer was less 

 well matured than that on the unmanured plot. In this case there 

 appears to be a slight increase in the percentage of nitrogen, due 

 entirely to the use of nitrogenous fertilizers. Comparing the grain on 



