Normal Institute 13&1 



Raw rock as an absorbent is as good as road dnst but has no 

 chemical effect in retaining ammonia. Acid phosphate has such 

 chemical value. 



Basic slag. On acid soils basic slag often gives excellent 

 results; on those slightly acid it may give as good returns as 

 acid phosphate. 



Floats. One need not expect returns from floats unless there 

 is an abundance of vegetable matter in the soil. Before using 

 extensively, farmers are advised to experiment on their particular 

 fields in a small way. 



POTASH 



Potash in feldspar is practically useless as plant food, but new 

 processes have been proposed which promise to convert feldspar 

 potash into a product that is available as plant food. 



SULPHUR 



The matter of using sulphur as a plant food is in an experi- 

 mental stage. There seems little warrant for it. On Long Island 

 its use was detrimental to plant growth. 



LIME 



^Nature has put lime into the soil in the form of carbonate. 



Ground limestone should be line enough to pass through a 

 screen of one hundred meshes to the inch. When ground lime- 

 stone can be laid down at $3, provided the haul is not too long, it 

 is probably the cheapest form to use. 



Slaking lump lime causes a large waste and under ordinary 

 circumstances is not economical. Ilydrated or water-slaked lime 

 is a desirable form, but one cannot afford to pay any more for it 

 than for the best forms of Imrncd lime. A larger amount will 

 need to be used in order to obtain the same amount of calcium. 



The question of the cheapest form in which to buy lime can be 

 decided with the help of the following table. Since 100 pounds 

 of quicklime is equal in value to 130 pounds of slaked lime or 

 180 pounds of carbonate of lime (freight and transportation not 



