EXPERIMENT STATION BULLETINS. 401 



Table 7. Result of field tests with rye on Cass Co. Soil 1918. 



Yield of grain. 

 Treatment. Bus. per acre. 



16 per cent acid pliosphate 200 pounds per acre 



Sodium nitrate 50 pounds in fall and 50 pounds in spring 28.66 



Muriate of potash 200 pounds per acre 



No treatment 



Increase due to fertilizer 



16 per cent acid phosphate 200 pounds per acre 



Sodium nitrate 50 pounds in fall and 50 pounds in spring 



Increase in yield over untreated 



This soil is deficient in vegetable matter, and responds to applications 

 of complete fertilizers and its judicious use under normal conditions 

 at least until clover is established in the rotation is profitable. Sweet 

 clover responds vigorously to lime and phosphorus on this soil as illus- 

 trated by figure 21. When this crop is established in the rotation of 

 course the nitrogen situation is largely solved. 



Duplicate field tests were conducted on a sandy soil in Kent county in 

 co-operation with H. G. Smith. Where 300 pounds of 1Q% acid phos- 

 phate were applied to the soil the yield of potatoes was materially in- 

 creased. 



Table 8. Results of field tests on Kent County Soils— 191G. 



Yields per acre 

 Treatment. bushel. 



No treatment 100 



300 pounds of 16 per cent acid phosphate 132 



In cooperative experiments with S. A. Foster, of Ingham county, 

 applications of lime as marl and either acid phosphate or raw rock phos- 

 phate have resulted profitably. (See figure 8.) The soil in question is 

 a light sandv one, badlv in need of lime as evidenced bv the numerous 

 failures to obtain suitable stands and yields of clover. Although this 

 soil is not suitable for the production of oats, this crop was seeded the 

 first season as a nurse crop for clover. The presence of the lime and 

 phosphates increased the yield of oats and resulted in an excellent catch 

 of clover. The following season the clover on the treated portion of the 

 field outyielded that on the untreated land and was of much better 

 quality. Moreover, about one bushel of seed was obtained per acre. 



The co-operative investigations with several farmers have been gratify- 

 ing indeed. The aft'ects of acid phosphate when applied to several soils 

 are illustrated by means of photographs. 



Nummary and Conclusions. The mineral element of plant-food, phos- 

 pliorus. is popularly referred to as pliosphoric acid and pliosphate. 



The three chief carriers of phosphorus are raw rocli phosphate, bone 

 meal and acid phosphate. 



The application of phosphorus in suitable amounts to soils deficient 



