EXPERIMENT STATION BULLETINS. 



439 



Finely .uroiiiid bone ov l)()iie meal is oblaiiRMl Cioiii i>ackiug aii<l oilier 

 slaiij;lil(M- houses and is somewhat more active in its ettect ou the ei-ops 

 than' raw rock phosphate and therefore the applications consist of some- 

 what smaller amounts. 



Acid phospliato, the most extensively used in Michigan, is derived 

 cliielly li'om raw rock phosphate and is manufactured by adding about 

 one ton of strong sulphuric acid to one ton of the floats. As a result of 

 this mixture the acid is neutralized and the phosphorus is converted 

 into a much more active or available condition. Bone meal may be treated 

 in a similar manner. The product obtained is commonly spoken of as 

 acidulated bone, or soluble bone and the phosphorus exists in the same 

 form as it does when floats are treated with the acid. 



J<'isiire 1. — Alfalfa is an exacting crop requiring an abundance of lime and other elenienls til' 

 plant-food. The plants on the right are typical of those growing on limed sandy soil, those 

 on the left were taken from the same soil to which had licon applied lime and 300 pi.nnds 

 of acid phosphate per acre. Ingham County sandy soil. 



Effect of PJiosphorus on Crops. An application of phosphorus in suit- 

 able quantities to soils deficient in this plant-food element proves to be 

 beneficial in several respects. It is known to increase tremendously the 

 root production of plants, causing them to strike more deeply into the 

 soil as well as to be more numerous in tlie surface soil. This has been 

 reported to be of value during periods of drouth, enabling the plant to 

 draw upon larger areas of soil for water and elements of plant-food. It 

 results in greater leaf and stem development, and aids materially in 



