VI Journal of Agricultural Research voi. xvii 



Page 

 6B, all leaf mold (control series). V, VI. — Influence of the amount of 

 organic matter in the soil on injury by tobacco rootrot: V, 1A-5A, Influence 

 of gradually increasing amounts of organic matter in tminf ested soil from i A, 

 no organic matter, to 5A, all leaf mold (control series); VI, 1B-5B, Influ- 

 ence of gradually increasing amounts of organic matter in infested soil from 

 iB,noorganicmatter, to 5B, all leaf mold 86 



Plate 5. I. — Influence of relative amount of sand and clay on tobacco rootrot: 

 A, uninfested series: B, infested series — lA, iminfested soil, three-fotirths 

 clay and one-foiorth sand; iB, infested soil, three-fourths clay and one- 

 fourth sand; 2A, uninfested soil, one-half clay and one-half sand; 2B, 

 infested soil, one-half clay and one-half sand; 3A, uninfested soil, three- 

 fourths sand; 3B, infested soil, three-fourths sand; 4A, uninfested soil, all 

 sand; 4B, infested soil, all sand. II, III. — Influence of soil fertility on 

 amount of tobacco rootrot: II, infested series; III, uninfested series — 

 lA, infested soil, no treatment; 2A, infested soil, 3.5 gms. of nutrient salts; 

 3A, infested soil, 7.Q gms. of nutrient salts; 4A, infested soil, 14.00 gms. of 

 nutrient salts; 5A, infested soil, 28 gms. of nutrient salts; 6A, infested soil, 

 56 gms. of nutrient salts. Note increasing injury from nutrient salts 

 beginning at pot 3 A. iB, iminfested soil, no treatment; 2B, iminfested 

 soil, 3.5 gms. of nutrient salts; 3B, iminfested soil, 7.0 gms. of nutrient 

 salts; 4B, iminfested soil, 14.00 gms. of nutrient salts; 6B, uninfested soil, 

 28 gms. of nutrient salts; 6B, uninfested soil, 56 gms. of nutrient salts. 

 Note injury from nutrient in pots 5B and 6B. IV. — Relation of com- 

 pactness of soil to injury caused by Thielavia basicola: lA, infested soil, 

 loosely packed; iB, uninfested soil, loosely packed; 2A, infested soil, 

 very compact; 2B, iminfested soil, very compact. V. — Influence of 

 transplanting infected seedlings in healthy soil: A, Pennsylvania 

 Broadleaf infected seedlings; B, Pennsylvania Broadleaf healthy seedlings 

 C, WTiite Burley infected seedlings; D. White Burley healthy seedlings; 

 E, Northern Hybrid (a resistant type) infected seedlings; F, Northern 

 Hybrid (a resistant type) healthy seedlings 86 



Plate 6. Soil temperature graphs for the month of June, 1915-1918, inclusive, 



at depths of 2, 4, and 8 inches 86 



Plate 7. Soil temperature graphs for the month of July, 1915-1918, inclusive, 



at depths of 2, 4, and 8 inches 86 



Plate 8. Soil temperature graphs for the m.onth of August, 1915-191S, in- 

 clusive, at depths of 2, 4, and 8 inches 86 



Relatio.nt op Sulphates to I^lant Growth and Composition' 



Plate 9. A. — Clover on soil A. The top row, reading from left to right, shows 

 the soil pots \\hich received the following fertilizers: Pot i, calcium 

 sulphate, sodium nitrate; pot 2, sodium sulphate, sodium nitrate; pot 3, 

 sulphur, sodium nitrate, calcium carbonate; pot 4, sodium nitrate; pot 5, 

 sodium nitrate, calcium carbonate; pot 6, no fertilizer; pot 7, calcium 

 sulphate, sodium nitrate; pot 8, sodium sulphate, sodium nitrate; pot 9, 

 sulphur, calcium carbonate, sodium nitrate; pot 10, sodium nitrate. 



B. — Clover on soil B. C. — Clover on soil C 103 



Plate 10. A. — Rape on soil A. B. — Rape on soil B. C. Rape on soil C. . . . 102 



Pl.-\te II. A. — OatsonsoilA. B. — OatsonsoilB. C. — OatsonsoilC 102 



Plate 12. A. — Oats on sand cultures from soil A. B. — Oats on sand cultures 



from soil B. C. — Oats on sand cultures from soil C 102 



