The Bulletin 75 



quantities of potash, the nitrogen, and phosphoric acid remaining 

 constant. On one plat only one-half the normal quantity of potash was 

 applied or 1.1 per cent in the fertilizer mixture, or 2.25 pounds of 

 potash per acre. On two other plats two and three times the normal 

 quantities were given, or 9 and 13.5 pounds per acre respectively. 

 This would make the application of potash on the several plats 2.25, 4.5, 

 9, and 13.5 pounds. The results on an average show that the most 

 profitable application is one containing one-half normal potash with 

 normal quantities of nitrogen and phosphoric acid. 



The indications are that 1^/2 per cent of potash is all that is needed 

 for corn in this soil when used in connection with the regular quantities 

 of nitrogen and phosphoric acid in the normal corn mixture. 



Effect of Varying Quantities of Fertilizer on Yields. — These tests 

 show the effect of inci'easing and decreasing the normal fertilizer appli- 

 cation on yields, the normal (IST P K) being 300 pounds of a mixture 

 containing 7 per cent phosphoric acid, 3 per cent nitrogen and IV2 per 

 cent potash. The applications were at the rate of 150 pounds per acre 

 (V2N" P K) ; 300 pounds per acre (IST P K) ; 450 pounds per acre (IV^ 

 N" P K) ; 600 pounds per acre (2 N P K) ; 750 pounds per acre (21/2 

 ]Sr P K). The results in all the fields show increased yields and profits 

 for all the quantities of fertilizer. The average results of the two 

 fields taken together show that 150 pounds per acre is the most profitable 

 quantity of the fertilizer mixture to use for corn. 



FERTILIZER EXPERIMENTS AT IREDELL TEST FARM. 



The main type of soil on the farm is red (Cecil) clay loam, the sub- 

 soil being a moderately heavy clay, but the surface soil has sufficient 

 sand in it to make it a clay loam rather than -a clay, though when freshly 

 plowed it would to a casual observer be looked upon as red clay. The 

 main types of soil in the Piedmont are Cecil sandy loam (gray land), 

 red (Cecil) clay loam and red (Cecil) clay. The clay and clay loam 

 types are rich in potash, very poor in phosphoric acid, the amount of 

 nitrogen depending on the organic matter in the soil. 



The plats on which these experiments were conducted were embraced 

 in Fields A, E and C. Fields A and B had been long in cultivation and 

 were badly run down when work was started in 3 903. The plats in 

 Field A were laid off in two series parallel to each other, there being 

 twenty plats to the series, with a driveway or turn row between plats. 

 The plats are one-tenth acre in size, or 217.8 feet by 20 feet, with space 

 between plats sufficient for two rows of corn or other crops, the row on 

 either side of each plat being fertilized like the plat which it adjoins. 



The plats in Field B were laid out in a similar way and are of the 

 same size. 



The plats in Field C were part of an old field, covered with broom 

 sedge, briars, and small pines in 1903. The pines were grubbed out 

 and the other growth turned under with a two-horse plow in the spring 

 of 1903 and cultivated in corn that year, with a fertilizer application 

 of 300 pounds per acre, of the normal corn mixture. In the fall of 

 1903 crimson clover was sown but no stand was obtained. The land 

 was prepared in the spring of 1904 and laid off in plats of one-twentietk 



