16 



phosphate, and sulphate of potash produced the best quality- of leaf. 

 These tests were continued in 1893/ and the results indicated that nitro- 

 gen was needed most, while potash was the least necessary. Complete 

 fertilizer mixtures gave the best results, in some cases increasing the 

 yield over 100 per-cent as compared with a crop grown without the 

 use of fertilizers. 



The results of the work carried on in 1894 and 1895 2 confirm the 

 conclusions drawn from the experiments of the preceding seasons 

 and indicated that cotton-seed meal was the best and cheapest source 

 of nitrogen for the tobacco crop in that region. Since potash had 

 shown itself least effective in this series of experiments it is concluded 

 that cotton-seed meal and acid phosphate is the best tobacco fertilizer 

 mixture for the soils on which the experiments were made. 



The effects of different fertilizers on tobacco were studied at the 

 Virginia Station 3 in 1890. Five plats fertilized with complete fer- 

 tilizers, all of the same cost per acre, were compared with an unfer- 

 tilized plat. As a source of nitrogen, dried blood gave the largest 

 yield and the best financial returns. Dried blood in connection with 

 nitrate of soda also gave good results, and where these fertilizers 

 were applied, either in combination or separately, the tobacco fired 

 very little as compared with the tobacco grown on the unfertilized 

 plat. There was also much more stalk rot on the unfertilized plat 

 than on the other plat:;. The plat which had received sulphate of 

 ammonia, sulphate of potash, and acid phosphate suffered most from 

 field fire and gave smaller returns than any other of the fertilized 

 plats. The tobacco grown without fertilizers ripened from ten days 

 to two weeks later than the tobacco grown with fertilizers. 



In 1893 the Pennsylvania Station 4 made some experiments to deter- 

 mine the relative values of various fertilizers for tobacco. The use of 

 fertilizers increased the size of the wrapper leaves, and an application 

 of double carbonate of potash and magnesium, contrary to the claim 

 sometimes made for it, had no restraining effect on the size of the leaf. 

 The loss in sweating the crop was greatest where barnyard manure had 

 been used. Phosphoric acid in the form of dissolved bone black 

 showed a tendency to thicken the leaf, and nitrate of soda produced a 

 very dense leaf. Double carbonate of potash and magnesium produced 

 a thinner web than sulphate of potash, but had little effect upon the 

 vein. As to burning quality, no decided differences were noticed, 

 except that the duration of glow was least in the crop fertilized with 

 barnyard manure. 



In connection with soil tests made by the North Carolina Sta- 



1 Louisiana Stations Bui. No. 25, 2d ser. 



2 Ibid. Nos. 33 and 41, 2d ser. 



3 Virginia Station Bui. No. 12. 



* Pennsylvania Station Bui. No. 30. 



