Alfalfa in Kansas. 



463 



mals. A notable feature of their nutritional characteristics is the high 

 per cent of nitrogenous material, especially proteins, present in them. 

 The presence of these nitrogenous substances constitutes one of the most 

 important factors involved in the relation of alfalfa to soil fertility. In 

 respect to metals present, alfalfa, like red clover, beans, peas and other 

 leguminous plants, is notable for the large amount of calcium in its 

 tissues. This metal is that found in limestone and lime, and in gypsum 

 or land plaster. The needs of alfalfa for .calcium extends to the re- 

 quirement that the calcium carbonate of limestone be present in the soil 

 in such quantities as to insure neutralization of the acids produced by 

 the decay of organic matter, as well as to supply the necessary calcium. 

 The accompanying table shows a comparison of the percentages of 

 potassium, phosphorus and nitrogen present in the feeds named. 



TABLE No. 52. Fertilizing constituents in certain feeds. Pounds per hundred-weight of the 

 x substances.* 



*Data obtained from Henry's "Feeds and Feeding." 



The draft of any crop on the fertility of the soil depends not only on 

 the composition of the crop but on the total weight of the crop. Taking 

 as a basis the composition shown in Table 52, Table 53 shows the quan- 

 tities of the several constituents that would be removed per acre with 

 the yields stated. The yields assumed, and the relation of grain to 

 stover or straw, have been chosen largely on the advice of Prof. L. E. 

 Call, who has made numerous observations at the Kansas Experiment 

 Station. The yields assumed are very moderate when compared with 

 possibilities and with actual products often obtained, but are in excess of 

 the average in this state. It need hardly be stated that with the great 

 differences in the yields of grain, depending on seasonal characteristics, 

 there are correspondingly great differences in the relation between grain 

 and straw. 



Inspection of Table 53 shows that alfalfa exceeds all of the other 

 crops in the list in total yield, and far exceeds them in the weights of 

 potassium, phosphorus and nitrogen contained in the crop. Attention 

 may be drawn to the fact that such tables serve only as general guides, 

 as the composition of crops varies considerably with the differences in 

 composition of soils. The most favorable results require at least certain 

 supplies of mineral substances, and probably definite quantitative re- 



