294 AGRICULTURE OF MAINE. 



Therefore we need some available commercial fertilizer to start 

 the crop in the spring before conditions have become favorable 

 for making the plant food in the soil available. This fact, 

 however, does not mean that the manure is not valuable and 

 that it i> not worth using. 



It is not my purpose to say whether the farmers should feed 

 or sell their cropsu This seems to me an economic question to 

 be decided by the farmer for himself and its solution depends 

 upon the profitableness of the method. Plant food can be sup- 

 plied in fertilizers and if the organic matter content of the soil 

 is kept up it will not decrease in productivity. I wish to empha- 

 size, however, the statement that the organic matter content of 

 the soil must be kept up, if we are to depend upon fertilizers 

 alone. 



The Pennsylvania Station has for thirty years kept up the 

 productivity of plots on which only mineral fertilizers, phos- 

 phoric acid and potash are used. However, a four year rota- 

 tion is followed, one crop of clover is grown and a heavy sod 

 plowed under every four years. The clover apparently sup- 

 plies nitrogen for the other crops, while plowing under the sod 

 keeps up the organic matter content of the soil. We cannot 

 say that under all conditions a crop of clover grown in this 

 manner would supply the nitrogen needed by the other crops, 

 but these results indicate that if organic matter is supplied, 

 soils will not decrease in productivity w-hen commercial ferti- 

 lizers instead of manure are used. 



However, most farmers keep a greater or less number of 

 live stock, and the question for consideration is : Can we not 

 secure better returns for the manure produced by our animals 

 than we are doing at present? The above statements are based 

 on the supposition that the manure is saved and returned to 

 the fields without any loss of the fertilizing elements. In prac- 

 tice, from one-half to one-third of the plant food value of the 

 manure produced in this country is lost and never reaches the 

 field. Some of this loss is unavoidable, but much of it can be 

 prevented. 



Now we will take up the losses in manure by which it is 

 deprived of some of the plant food excreted by the animal. We 

 will first consider the loss of the liquid manure which may 

 easily occur unless steps are taken to prevent it. The liquid 



