No. 7. 



DEPARTMENT OF AGRICULTURE. 



369 



crop can be estimated. Thus if from one acre we remove one and a 

 half tons of timothj bay, we remove |7.72 worth of fertility. Hence, 

 to maintain the soil fertility, so much must be returned each year. 

 But if that hay were fed, and the manure returned to the field, there 

 would be a deficit of but 11.93 in value. 



Contemplating these facts in the light of the history of most of 

 our farms in this State from which their products have been re- 

 moved year after year for a century, is it strange that our soil is 

 failing to produce the crops our grandfathers produced, or that we 

 so frequently hear the wail, ''farming does not pay." 



How", then, are these losses to be made up? Not wholly in the 

 use of commercial fertilizers, for they are too expensive and they 

 give no humus to the soil. Not altogether by the use of stable man- 

 ure, since there would be a deficit of twenty-five per cent, of what 

 was taken from the soil, even if all products were fed; while the 

 fact is that often not one-half of them is fed on the farm. 



It will be well at this point to inquire into the state of potential 

 fertility in the average Pennsylvania soils as revealed in the fol- 

 lowing analysis: 



o 



First 8 inches, per acre, . 

 Second 8 inches, per acre 



Total, 



17,597 

 6,843 



24,440 



These elements are chiefly locked up in the water-insoluble com- 

 pounds that must be corroded or oxidized to be brought into solu- 

 able forms available to the roots of the plants. This may, to some 

 extent, be accomplished by cultivation, turning the soil up to the air, 

 breaking up the soil grains and thus exposing an increased surface 

 to the action of oxygen. Another means of accomplishing this end 

 is the introduction of decaying vegetable matter, such as green crops 

 or stable manure, since in their decomposition certain acids are 

 liberated that attack and corrode the mineral compounds and thus 

 render portions of them soluble. This is true of all green manuring, 

 and, together with the great value of such growth as cover-crops 

 in preventing the waste of soluble fertility, such as the nitrites and 

 nitrates that have been formed in great abundance during hot 

 weather, shows the importance of always turning in a cover-crop 

 or a sod whenever a seed-bed is prepared. The crying demand of 

 our old soils for humus to retain moisture and stored sunshine for 

 the growth of our plants, to improve the physical condition of the 

 soil and make commercial fertilizers and lime more beneficial and 

 less harmful, must be heard and heeded by the farmers of this State 

 if their operations are to be profitable. Recent observations in 

 some of the hitherto richest counties east of the mountains, dis- 

 covered field after field whose surface soil is as colorless as is the 

 earth six feet below, and whose soil grains are drifting in the winds 



24—7—1904 



