l^l^J SOILS FERTILIZERS. 



517 



use as a top-dressing. When lime nitrogen was used a week before planting 

 and not too extensively used as a top-dressing for young sugar cane plants, there 

 was apparently no injurious effect. 



A partial displacement of ammonium sulphate with lime nitrogen gave better 

 results than a total displacement. In this connection the use of lime nitrogen 

 followed by ammonium sulphate gave the best results. Lime nitrogen showed 

 no influence on ripening. 



Comparative tests of sources of nitrogen on Coastal Plains soils, T. E. 

 Keitt (South Carolina Sta. Bui. 192 {1911), pp. S-i^).— This is a report of 

 comparative field tests lit Summerville, S. C, on reclaimed wet Coastal Plains 

 soil during 1911 to 1915, inclusive, of mixed fertilizers containing sulphate of 

 ammonia, nitrate of soda, cottonseed meal, fish scrap, dried blood, bone meal, 

 01- tankage, as nitrogen carriers. The fertilizers were applied at the rate of 

 600 lbs. per acre. Comparative tests were also made of dried blood, sulphate of 

 ammonia, and* nitrate of soda (120, 75, and 100 lbs. per acre, respectively), ap- 

 plied as top-dressings in addition to each mixed-fertilizer treatment. Yields of 

 corn, cotton, oats, and cowpeas for hay aro tabulated and discussed for each 

 combination indicated and the results summarized. 



Complete fertilizers for corn showed very small increases irrespective of the 

 source of the nitrogen, but organic sources gave slightly better results than 

 inorganic sources. The average yield from the 7 nitrogen carriers was 39 bu. 

 per acre, a gain of only 1.1 bu. over no fertilizer, and 1 bu. less than where no 

 nitrogen was used. This is held to emphasize the inadvisability of applying 

 nitrogen to this type of soil before planting corn. Dried blood as a top-dressing 

 showed an average increase of 5.4 bu., sulphate of ammonia 4.7 bu., and nitrate 

 of soda 3.7 bu. of corn per acre. These average results were lower in each case 

 than where the top-dressings were used alone, as follows : Dried blood alone 

 1.7 bu. more than where applied in addition to complete fertilizers, sulphate of 

 ammonia alone 5.S bu. more, and nitrate of soda alone 3.1 bu. more. Nitrogen 

 applied as a top-dressing gave better results in each case where the crop was 

 unfertilized than where it received an application of acid phosphate and potash 

 before planting. These differences were ; Dried blood 3.1 bu., sulphate of am- 

 monia 5.5 bu., and nitrate of soda 5 bu. per acre. 



Complete fertilizers showed material increases in the yield of cotton in every 

 case, the average yield from the 7 sources of nitrogen being 801 lbs. of seed 

 cotton per acre, a gain of 416 lbs. over no fertilizer, and of 171 lbs. over no 

 nitrogen, but the same amounts of phosphoric acid and potash. As an average 

 for the complete fertilizers, dried blood as a top-dressing showed an additional 

 gain of 419 lbs., sulphate of ammonia 412 lbs., and nitrate of soda 307 lbs. of 

 seed cotton per acre. Dried blood applied to cotton previously fertilized with 

 tankage gave the best results. 



Complete fertilizers applied to oats showed widely varying results where 

 top-dressed, but better results than where no top-dressing was used. Sulphate 

 of ammonia in a complete fertilizer gave the best results. The average increase 

 over no fertilizer was 13.7 bu., and the increase over an application of phos- 

 phoric acid and potash 1.2 bu. per acre. Top-dressings of dried blood applied 

 at the rate of 120 lbs. per acre showed an average increase of 24.6 bu., sulphate of 

 ammonia at the rate of 75 lbs. per acre 34 bu., and nitrate of soda at the rate 

 of 100 lbs. per acre 20.7 bu. per acre. The highest yield, 98.8 bu., was obtained 

 with a complete fertilizer containing nitrate of soda top-dressed with drietl 

 blood. 



The best average yield of cowpea hay was obtained where nitrate of soda 

 had been used as a top-dressing. 



