60 THE OLIVER PLOW BOOK 



the manure. As a matter of fact, any manure that is 

 spread below the roots is of little value to the plants 

 because if there is sufficient moisture in the ground to 

 raise what plant food may come from it in solution, 

 there will be a sufficient amount of water in the ground 

 to permit it to leach away, hence, the chief value of 

 manure as fertilizer is lost. 



Another serious objection constantly happening is 

 that a very heavy coat of barnyard manure is applied and 

 turned under in such a way that nitrates form too 

 rapidly in the spring on account of the ammonia content 

 of the manure and later in the season change into un- 

 available forms thus destroying the influence of the 

 manure, leaving the remaining part dry and in a form 

 that is hard to dissolve. This is what our scientists 

 term burning the soil. This dry, insoluble form of 

 fertilizer at that depth in the ground interferes most 

 seriously with the upward trend of moisture and retards 

 growth to that extent. 



While there is no question but that ultimately the soil 

 will be benefited by turning under manure at this depth 

 one can diminish a crop or lose it by a too zealous appli- 

 cation of manure at this depth, particularly if the ap- 

 plication is made close to planting time. 



It is easily possible for a soil that contains fertility to 

 be plowed deep in the fall and so improperly handled the 

 following spring that a crop cannot grow. For this 

 reason if a test with the soil pots proved that there was 

 plenty of fertility in the soil and the crop next year 

 proved a failure, it naturally follows that the deep plow- 

 ing in the fall would not be responsible for the failure. 

 This is not a mere hypothesis but has happened many 

 times when the failure of the crop has been wrongly at- 



