32 



to the 1,200 pounds of revised-formula fertilizer. In four instanc 

 gains were shown and in two instances there were slight losses. II 

 does not seem advisable, therefore, to recommend the addition of tl 

 quantity of sodium nitrate, either to be used in one application witl 

 the 1,200 pounds of the revised formula or" at intervals. 



EXPERIMENTS WITH VARIOUS COMBINATIONS OF FERTILIZERS. 



The effect of the application of acid phosphate alone at the rate o: 

 720 pounds per acre will be considered next. The data show the 

 yield of 13.33 tons per acre on field A and 9.97 tons per acre on field! 

 B. This shows an increase of yield per acre over that obtained on] 

 the blank plats (excluding the year 1902) of between 3 and 4 tons 

 on both fields. 



The effect of potash alone is shown in the next comparison, exclud- 

 ing the year 1902. The data show a yield of 14.62 tons per acre onj 

 field A and 10.55 tons per acre on field B. The addition of 120] 

 pounds of potash, therefore, produces a larger yield in this soil than 

 720 pounds of acid phosphate. The potash used was in the form of 

 potassium chlorid. An equivalent amount of potash used in the 

 form of kainit namely, at the rate of 490 pounds per acre did not 

 produce such large results, the average being on field A 12.51 tons 

 per acre and on field B 9.63 tons per acre. There is, however, quite 

 an increase over the unfertilized plats. 



The effect of cotton-seed meal alone was also tested for all the 

 years except 1902. The average yield per acre with the use of 480 

 pounds of cotton-seed meal on field A is 14.92 tons and on field B 

 11.38 tons. The principal fertilizing agent of cotton-seed meal is 

 nitrogen, although it contains considerable quantities both of potashl 

 and phosphoric acid. The data show quite a large increase in yield 

 over the blank plats about 5 tons in each field. 



Sodium nitrate was used alone only one year, namely, 1905, andj 

 the yield obtained on the single plat observed was 17.40 tons per ;KTO 

 on field A and 18.90 tons per acre on field B. This is about 6 ions 

 greater than the yield of the blank plats in field A in that year, .m<l 

 over 4 tons greater than the yield in field B. By reason of its being j 

 tried, however, on a single plat, the data are not so convincing as I 

 those that were derived from a larger number of observations. 



Experimental determinations were also made of the effect of mix- 1 

 ing two fertilizers only. The first test was with a mixture of 720 

 pounds of acid phosphate and 120 pounds of potassium chlorid perl 

 acre. For the four years the average yield per acre on field A with 

 this application was 16.90 tons and on field B 15.70 tons per acre, 

 being practically double that obtained without fertilization. The 

 grown on field A was 1 per cent richer in sucrose than that grow- 



