The Bulletin. 11 



Field A. — The plats were used for fertilizer experiments with cotton 

 in 1903-'04-'06-'08 ; and fertilizer experiments Avith corn in 1905-'07-'09. 

 In case of each of the two crops the same plan or system of fertilization 

 was followed. By this is meant that plat 8 in all cases received only 

 nitrogen and potash, plat 9 only phosphoric acid and potash, plat 10 

 a normal application of potash, nitrogen, and phosphoric acid, and so 

 on, though the quantities actually applied varied with the two crops. 

 The fertilization of the cotton plats was based on a normal application 

 of 400 pounds per acre of a mixture containing 7 per cent available 

 phosphoric acid and 2^ per cent each of nitrogen and potash. The 

 fertilization for corn was on a basis of 300 pounds per acre of a mixture 

 containing 7 per cent available phosphoric acid, 3 per cent nitrogen, 

 and 1^ per cent potash. 



Field B. — -These plats were used for fertilizer experiments with corn 

 in 1906 and 1908 and for fertilizer experiments with cotton in 

 1905-'07-'09. 



Preparation and Cultivation, 



The land in all cases was well prepared by breaking with a two-horse 

 turning plow in the winter, usually January and February, to a depth 

 of 8 to 10 inches, and allowed to remain this way until just before plant- 

 ing, when it was cut up thoroughly with a disk harrow. The rows were 

 run off 3% feet apart, the fertilizer distributed in the drill and covered 

 to a slight ridge, usually with one furrow of disk or other cultivator. 

 This was done some time prior to planting, so as to give the ground 

 time to settle before planting. Eussell's Big Boll was the variety of 

 cotton used in all the experiments. The cotton was planted as soon as 

 the weather would permit in the spring, on the slight ridge made in 

 covering the fertilizer, but which was usually brought to a level, or 

 almost to a level, by the cotton planter. The cotton was well culti- 

 vated Avith Aveeders, harrows, single and two-horse cultivators, requir- 

 ing not exceeding tAvo furrows to row, making the cultivation deep 

 at beginning and shallow toward the close of the season, when root de- 

 velopment of the plants was well extended into the soil. The cultiva- 

 tion was repeated each ten days to two weeks during the season, the crop 

 being laid by between July 15 and August 3, according to season. The 

 crop was thinned as nearly as possible to one stalk in the hill every 15 

 inches. 



Fertilization and Fertilizer Materials Used. 



As already stated, the fertilizer was applied in the drill just before 

 planting the cotton, the exact quantity of material for each row being 

 weighed out separately so that each row would get its proper amount 

 of the several fertilizer constituents. Acid phosphate was used as the 

 source of phosphoric acid ; dried blood as the source of nitrogen, except 

 where there was a comparison of different nitrogen-furnishing ma- 

 terials, or where nitrate of soda was used as a part of the nitrogen; 

 manure salt as the source of potash ; and rock or builder's lime for lime. 

 The fertilizer materials were analyzed each year and applications made 

 on the basis of actual analyses, so as to give the exact quantities of nitro- 

 gen, phosphoric acid, and potash required for each plat. For the sake of 

 simplicity and convenience in presenting the results of a number of 



