122 Keport of the Acting Director and Chemist op the 



bone-meal, dried blood, tankage, cottonseed -meal, ground rock, and 

 to some extent, soluble phosphates and potash compounds. 



Special Precautions. — In applying highly concentrated com- 

 mercial fertilizers, it is wise to prevent the fertilizer coming in 

 contact with the seeds or foliage of plants. 



Fertilizers containing ammonia compounds should not be mixed 

 with wood-ashes, lime, or Thomas slag (odorless phosphate), since 

 some of the ammonia is likely to be lost. 



On soils of loose texture and small retentive power, it is best tO' 

 use, for the most part, those forms of fertilizers which are not too 

 easily soluble, in order to make as small as possible the losses occa- 

 sioned by heavy rains. Animal and vegetable materials are espe- 

 cially suited for such cases. 



10. The Most Advantageous Methods of Using Farm-produced' 



Manures. 



Under this head we will discuss some of the more common points 

 relating to the use of stable-manure in its application to different 

 soils and crops. 



Exclusive and Long-continued Use not Advised. — The aver- 

 age farm-produced manure is a one-sided fertilizer, being excessively 

 rich in nitrogen in comparison with potash and phosphoric acid. A 

 ton of good stable-manure contains : 



10 pounds of nitrogen, 

 .5 pounds of phosphoric acid, and 

 10 pounds of potash. 



Now, if we compare these proportions of plant-food with those 

 found in different plants or with commercial fertilizers which are 

 successfully applied to different crops, we are readily impressed with 

 the one-sided character of stable-manure as a nitrogenous plant-food. 

 Where there is in the soil a sufficient amount of available potasK 

 and phosphoric acid to balance the excess of nitrogen furnished by 

 the application, then most excellent crops are secured by the exclu- 

 sive use of stable-manure. But it must be evident that, under such 

 treatment, the crops each year take from the soil more potash and 

 phosphoric acid than is replaced by the stable-manure. Hence, 

 each year the available supply of these two constituents in the soil 

 becomes less ; and, when they are insufficient to balance the nitrogen 

 applied, then crops become smaller and further exclusive applica- 



