334 



STATE BOARD OF AGRICULTURE. 



district it seems from our present knowledge that combinations of acid 

 phosphate and sodium nitrate will give the most profitable returns. 



Figure 11. — Acid phosphate fwhere'needed improves the'qiiality of grain. On the right, grain grown 

 ou phosphated land; on the left, none. W. J. Guthrie Farm, Mendon. 



The results obtained in Cass county are striking. Experiments were 

 inaugurated in 1917 on the Cass county field spoken of previously. Acid 

 pliosphate was applied twice during a four-year rotation on land limed 

 at the rate of 3.15 tons per acre. A four-year rotation of soybeans for 

 seed, rye, wheat and soybeans for green manure was followed with tlie 

 following increase in yields: Soybeans, .02 bushels; rye, 2.10 bushels; 

 wheat, 1.93 bushels and 450 pounds of green weight in so^'beans. The 

 profit above the cost of material amounted to 71 cents per acre. Where 

 acid phosphate was combined with sodium nitrate (100 pounds per acre 

 each year) on the same soil and the same rotation it gave the following 

 increases in yield over limed check plots: soybeans, .77 bushel; rye, 

 4.09 bushels ; wheat, 10.07 bushels, green weight of soybeans 680 pounds 

 or returns of $11.44 per acre after deducting costs of materials. When 

 acid phosphate was used in connection with sodium nitrate (100 pounds 

 per acre per rotation) and 100 pounds of muriate of potash per four- 

 year rotation the increase over the lime-treated check amounted to the 

 following: Soybeans, 1.07 bushels; rye, 10.42 bushels; wheat, 14.94 

 bushels and green weight of soybeans 680 pounds or a profit after de- 

 ducting the cost of material of |22.20 per acre. 



Similar tests are being conducted on two poor sandy soils in Manistee 

 county. Acid phosphate when used alone at the rate of 250 pounds per 

 acre has increased the average yield of rye on the two fields, 9.22 bushels 

 and 620 pounds of straw. Although this is only the first crop of a four- 

 year rotation after deducting the cost of the materials a profit of |13.83 

 per acre remains. On the same soil acid phosphate in combination with 

 sodium nitrate (100 pounds per acre per year) gave an average increase 

 of rye over an untreated plot of 12.28 bushels of grain and 612 pounds 



