EXPERIMENT STATION BULLETINS. 363 



iu combination with nitrogen and potash have been used. From one 

 crop of oats and two crops of clover .|6.64 per acre have been obtained, 

 that is above the cost of the phosphate. On the same field rock phos- 

 phate has been used at the rate of 1,000 pounds per acre in conjunction 

 with 10 tons of barnyard manure. After having deducted the cost of 

 the phosphate returns of §1479 per acre have derived from one oat crop 

 and two clover crops. 



The use of rock phosphate at the rate of 2,000 pounds in conjunction 

 with marl the first two years of a four-j-ear rotation has shown a net 

 loss of -f22.35 per acre on the farm of Jas. Eichards near Eau Claire. 

 The soil is a silt loam with a tight subsoil. 



LIGHTER TYPES OF SOIL. 



Bock phosphate wlicre used on the lighter types of soil has not been 

 as promising in the early stages of the tests as it has when used on 

 heavy land. 



Applications of 2,000 pounds of rock phosphate with 3 tons of lime 

 per acre were made on the Cass county farm near Cassopolis. At the 

 end of a four-year rotation of soy beans for seed, rye, wheat and soy 

 beans for green numure, a loss of 84 cents per acre was obtained. 



Experiments carried on with sandy soil in lOmmet and Cheboygan 

 counties where 2,000 pounds of rock phospliate have been used alone, 

 sliow an average loss of |12.94 per acre on the first crop of a four-year 

 rotation. 



Applications of rock phosphate to a portion of an outwash sand plain, 

 belonging to E. D. Fairchilds, resulted in a loss of iiflS.TS per acre from 

 two crops, corn and rye, of a four-year rotation. 



TESTS WITH ACID rHOSrilATB. 



The results obtained from experiments with the use of acid phosphate 

 alone and together with combinations of lime, nitrogen and potash vary 

 considerably on heavy and light soils. 



LIGHT SOILS^ SAND TO LIGHT SANDY LOAMS. 



Experiments are being conducted on sandy soils in Emmet and Che- 

 boygan counties. The soil types are hardwood sands with light to 

 medium heavy subsoils. Acid phosphate was applied at the rate of 

 250 pounds per acre on three separate areas. The average increase of 

 rye for the first year shows 3.73 bushels of grain and 173 pounds of straw 

 over adjacent unphosphated lands. For the first year this gives returns 

 of |2.28 per acre after deducting the cost of the acid phosphate. On 

 the same lands a CDmbination of 250 pounds of acid phosphate and 

 sodium nitrate (100 pounds per acre) was used on rye. The treated 

 plots yielded an increase of 13.82 bushels of grain and 219 pounds of 

 straw, or when the cost of both sodium nitrate and acid phosphate are 

 considered, returns of |13.10 per acre. On the same lands combinations 

 of 250 pounds of acid phosphate, 100 pounds of sodium nitrate and 100 

 pounds of muriate of potash were used. The combination of the three 

 materials gave an increase of 11. G7 bushels of grain and 823 pounds of 

 straw per acre. The returns from the first crop above the cost of ma- 

 terials amounted to ^oAd per acre. Under the conditions of land in this 



