The Value and Use of Farmyard Manure 1685 



phosphoric acid at three cents per pound, twentj-four cents ; and 

 the potash at three cents per pound, twenty-seven cents. Giving 

 lis a total value per ton of one dollar and forty cents in round 

 numbers. This is a fairly generous allowance for plant food 

 contained in the average sample of horse manure, and if we were 

 to buy it for the plant-food alone, we could afford to pay no more. 

 Calculated in the same manner the average sample of cow manure 

 has a value not greater than one dollar or one dollar and ten 

 cents per ton. However, animal manures contain something 

 aside from their nitrogen, phosphoric acid and potash, that may 

 render them important or even indispensable for certain soils and 

 for certain crops. The average sample of horse manure contains 

 four hundred and fifty or five hundred pounds of organic matter 

 per ton and it contains in addition countless numbers of bacteria. 

 It is not a simple matter to place a definite value on these two 

 constituents of manure. For some soils and crops they may be 

 worth nothing. Occasionally they may be a hindrance rather than 

 a benefit. For other soils and crops they may prove of incalcu- 

 lable advantage. Soils poor in humus and limited in their power 

 to retain the rain which falls upon them would most readily re- 

 spond to additions of these constituents. Heavy soils well pro- 

 vided with humus and plant food might derive but slight advan- 

 tage from the humus making material and bacteria supplied in 

 manure. Yet, generally speaking, it would be unwise to make 

 an allowance for these materials. We should not really include 

 them in our valuation of the plant food, and should not pay more 

 than one dollar and fifty cents per ton for horse manure, and 

 one or one quarter dollars for cow manure. Beyond that we 

 should be paying for something which would give us very un- 

 certain returns. If a greater valuation is to be placed at all on 

 animal manure, it may be made in connection with run do^vn 

 soils largely depleted of their available plant food and of their 

 humus. In the restoration of all such soils the humus forming 

 material and the bacteria present in the manure may produce 

 effects that green manures and commercial fertilizers would pro- 

 duce but slowly. 



The valuation placed on farmyard manure by the trucker and 

 gardener is naturally greater than that placed on it by the general 



