The Bulletin. 7 



was the rock used in these experiments. It contained 28.95 per cent 

 of total phosphoric acid. 



I. Nitrate of Soda Tests with Cotton. 



PLAN OF EXPEEIMENTS. 



These experiments were designed especially to study the action 

 and suitability of nitrate of soda as a carrier of nitrogen to the cot- 

 ton crop. They were conducted at the Edgecombe farm on seven 

 one-tenth acre plats, which were carefully staked off on a piece of 

 land of moderately uniform character throughout. The plats fol- 

 lowed each other with an unfertilized row between the plats. 



Plat 1 was left without fertilization of any kind, while plat 2 

 was given during both years an application of 20.0 pounds of acid 

 phosphate and 8.3 pounds of kainit or its equivalent of potash in 

 the form of manure salt. The remaining plats have received in addi- 

 tion to acid phosphate and kainit (or manure salt) annual applications 

 of nitrate of soda to each in varying amoimts and divided differently ; 

 part being added just before planting the seed, and the remainder 

 being reserved and applied as a side-dressing the latter part of June 

 in 1905, and the latter part of July, in 1906. In addition to acid 

 phosphate, kainit or manure salt and nitrate of soda plat 7 has also 

 received an application of dried blood at planting at the rate of 40 

 pounds per acre. These experiments have been conducted two years, 

 and the individual plats during this time have each occupied the 

 same land and received the identical application applied in the same 

 way both years. The cotton was planted at the rate of one bushel 

 per acre in rows 3 feet 4 inches apart, using seed of King's Improved 

 variety for planting. When the plants had attained sufficient height, 

 they were reduced to and maintained as nearly as possible at a stand 

 of one plant to every fifteen inches in the row. The perfectness of 

 the stand in the several plats during 1905 and 1906 is shown in 

 Tables I and II by comparing the figures contained in the fourth 

 with those recorded in the third column. The soil at the Edgecombe 

 farm devoted to these tests was on the poorer phase of the type of soil 

 of the farm and was rather in a run-down condition and contained 

 relatively only a small quantity of humus. 



