No. 6. DEPARTMENT OF AGRICULTURE. 377 



We must muke the soil the basis of plant growth, and make fertili- 

 zers simply the adjunct. We must learn to use the soil and not 

 abuse it. By a rational use of commercial fertilizers, by husbanding 

 the home sources of fertility, by a judicious use of cover crop on 

 every possible occasion, these combined with thorough tillage will 

 solve the problem of a balanced ration for plants. 



RELATIVE VALUE OF FODDERS. 



BY PROF. WELLS W. COOKE, Washington, D. C. 



The subject is capable of several different treatments, of which 

 two will be chosen. It will be treated lirst, from the standpoint 

 of the relative value of foods for keeping the animal alive. When 

 an animal is fed just enough to keep it in health, neither gain- 

 ing nor losing in weight, performing no work and producing 

 nothing for the service of man, it is said to be receiving a mainte- 

 nance ration. Such a maintenance ration needs to supply three 

 things. First, it needs to repair the slight waste of the body that 

 is all the time taking place. Secondly, it needs to supply the mus- 

 cular force used by the body in operating the lung®, keeping up the 

 circulation of the blood and supplying the energy used in mastica- 

 ting and digesting the food and carrying it along through the ali- 

 mentary canal. Every animal also uses some muscular force in the 

 slight movements that are made, in getting up and down and in 

 holding itself erect. Thirdly and lastly, the food must supply heat 

 to take the place of that which is radiated from the body and is 

 carried off in the sensible and insensible excretions. 



The first of these needs is the most important in the sense that 

 we have the least control over it. Under the conditions of mainte- 

 nance the body does not waste very fast, but this waste must be sup- 

 plied or the body loses in weight, and the food must also contain all 

 of the different ingredients, i. e., materials for making bone, flesh 

 and fluids. The amount required for the other two purposes can be 

 somewhat regulated by man. The animal can be placed in a stable 

 warm enough to lessen the requirements for heating the body, and 

 by the use of concentrated food, the amount of force required in 

 mastication and digestion can be largely reduced. 



When the food furnished is less than maintenance, the order of 

 use is first to keep up the heat of the body, because if the body cools 

 but a little below normal, death ensues at once. At the same time, 

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