THIRTY-EIGHTH ANNUAL CONVENTION 27 



to keep up the humus of the soil. When you feed a ton of hay 

 the cow will use about two-thirds of the dry material of the 

 hay as fuel. In other words, the manure resulting from a ton 

 of dry feed will contain about one-third of a ton of dry matter. 

 We can state this in still another way to make the problem 

 clearer. If one ton of clover is plowed under, we will add as 

 much organic matter as if we feed about three tons of clover 

 and return the manure to the land. This also involves every 

 care to prevent loss of manure from decomposition, leaching or 

 washing. An acre of corn stalks plowed under will add as 

 much humus as the manure resulting from feeding the corn 

 stalks in three acres of silage. Of course, the amount of organic 

 matter destroyed in dairy feeds depends upon the digestibility 

 of the feed. Corn stover or straw is not nearly so completely 

 eaten or digested as grain, alfalfa bay or silage. Then, too, the 

 straw and other refuse used for bedding can be returned as a 

 whole besides serving a very useful purpose by absorbing the 

 liquid manure. When it comes to a consideration of the plant 

 food elements, it is possible to return three-fourths of the nitro- 

 gen and phosphorus contained in the feeds fed. In order to do 

 this, the stock must be well bedded, and liquid as well as solid 

 manure must be saved. One- fourth as a general average of 

 the nitrogen and phosphorus contained in the feed will be used 

 by the cattle to form milk, flesh and bones and to build up worn- 

 out tissues. 



With other plant food elements, various relationships ex- 

 ist, but we need to give serious attention only to those elements 

 that limit our corn yields. For example, potassium is needed 

 by all plants as a food, but with the exception of peat soils, it 

 seldom becomes necessary to add to it as an element of plant 

 food for crops on the average soils in dairy districts of Illinois. 

 Most of our soils contain in the plowed land enough potassium 

 for maximum crops for a thousand or more years. It is merely 

 a problem of farming the land so that the crops can secure 

 enough for the largest growth during the growing season. 



The first problem the dairyman needs to give consideration 

 is to study his soil and know its needs. He should not spend mon- 



