FIELD CROPS. 747 



fertilizers being;' used on the same plats year after year. The crops were 

 rotated. Where only 1 ingredient was used nitrogen had the greatest 

 influence on the yield, and where 2 ingredients were combined nitrogen 

 and phosphoric acid gave the best results. The plat with all 3 ingre- 

 dients gave very little increase over the plat receiving nitrogen and 

 phosphoric acid. 



Field experiments with fertilizers, C. E. Thorne, J. F. Hick- 

 man, and W. J. Green (Ohio Sta. Bui. 80, pp. 143-175, Jig. 1). — The 

 general plan of this experiment has been outlined in a former bulletin 

 (E. S. B., S, p. 576). The work comprises fertilizer tests with crops 

 grown continuously on the same land and in .*> and 3 year rotations. 

 This bulletin reports in tabular form the results obtained in 1890 and 

 the average results for the 3 years the experiments have been in 

 progress. The results are discussed and conclusions drawn. 



The authors found that on the clay soils phosphoric acid appeared 

 to be the most effective fertilizer constituent for cereals and clover in 

 rotation, but that its full effect was attained only when applied with 

 nitrogen and potash. The quantities of nitrogen and potash in the fer- 

 tilizers used are considered greater than necessary for the full utiliza- 

 tion of the phosphoric acid, and the indications were that nitrogen and 

 potash applied in about equal quantities with phosphoric acid largely 

 in excess makes the most effective fertilizer in proportion to the cost. 



"In the continuous culture of cereals nitrogen appears to be the most important 

 constituent of the fertilizer, but as in rotative cropping. it is the complete fertilizer 

 containing phosphoric acid and potash as well as nitrogen which produces the max- 

 imum effect. . . . 



"The cost of the fertilizer has been greater than any increase prod need from it 

 in crops grown continuously on the same land in these experiments. When the 

 cereals have been grown in rotation with clover the cost of the fertilizer has been 

 recovered with a margin to spare, provided nitrogen and potash were used in small 

 proportion relatively to phosphoric acid, and when potatoes formed one crop in the 

 3-year rotation with wheat and clover, it has been comparatively easy to secure a 

 profit on the fertilizer. 



"In rotative cropping, ordinary barnyard manure has produced an increase to the 

 value of $1 to $1.50 for each ton of manure, this increase being found chiefly in the 

 hay crops, whereas the increase from chemical or slaughterhouse fertilizers is shown 

 chiefly in the grain crops. . . . 



"The nitrogen, phosphoric acid, and potash in wheat bran and linseed meal seem 

 to be nearly or quite as effective in producing increase of crop as the same constitu- 

 ents in the ordinary mixed fertilizers of commerce. . . . By proper care of the 

 manure, a large portion— prohably the larger portion — of the cost of these valuable 

 feeding stuffs may be recovered in the manure." 



Tests of fertilizers on wheat, D. O. Nourse ( Virginia Sta. Bid. 

 69, pp. 109-111). — This is in continuation of work reported in Bulletin 47 

 of the station (E. S. 11., 8, p. 221). Suggestions relative to making plat 

 experiments are given, and the results are tabulated. 



Nitrogen, phosphoric acid, and potash were applied singly and in 

 combinations of 2 and 3. The standard application consisted of 142.5 



