l-U MASS. ]>:XPKHI.MI':XT STATION' lUT.I .I'/I'lX -JTfi 



Tai!lk 7. — Effkct or sri.i ru on I'l 1 \.\iii:s oi- sou i\ I'lr.iu >'. 



pll values of soil 



Oil' Grades of Leaf 



These coiiip.irison.s are ha.sed on ihe ])erceiitage.s of tobacco from each 

 jtlot which were sorted into lights, mediums, and seconds, as contrasted with 

 darks and fillers. (See Tables 11-14, for the years 192(i, l<»2r, I!)28, and 192(».; 



On this basis, the grades as well as the yield of tobncco on limed plots 

 \\ere improved in 1!)2() and 1927 by the use of sulfur or the acids, sulfuric 

 and orthojihosphoric. In 1927, tlie grades of the tobacco on plots not limed 

 were either imj)roved or unaffected by the a])plications of sulfur in 1!I2() .ind 

 1927. 



Qunlity wns jioor on most of the phits in the very i;iiiiy summer of 1928 

 in which the acidification treatments were ineffeeti\c in increasing yields. 

 The only treatment which resulted in imprcncd grades of tobacco on limed 

 ])lots in the lower ]iart of the field th;it \ear was the application of sulfuric 

 :ind orthopliosphoric acids in 192(). This treatment as well as sulfur, 2(Hi 

 pounds j)er acre applied in 192() or in 192() and 1927, improved the (|u;ility of 

 tobacco on limed plots in the higher jtart of the held. 



In 1929, with larger yields and better tjuality of tobacco on lim<'d j)lots 

 than in earlier years, the quality of tobacco was not affected by the acidific.i- 

 lion treatments either on ])lots limed or on plots not limed. 



In 1930, with black root-rot less severe than in earlier years, the per 

 centage of leaves of the grades lights, mediums, and seconds on limed ])lois 

 ncidified (except by sulfur, 200 pounds per acre applied in 192(>) were :\ 

 little less tli.in Ibe ])ercentages of leaves of these grades on limed plots nnl 

 acidilied. 



In 192(>, 1927, ;md 192f), however, the (|uality of ihe tobacco was not in- 

 jured by the sulfur or the acids used on this soil. Similarly, in the e\|ieri- 

 ments of McKibben (2.3) the quality of tobacco was not afl'cclcd liy sulfur 

 apjilied to the soil. 



On. Hum 



In experiments of Murwin (2-5), sulfates (of sodium or magnesium) did 

 not injure the burn of tobacco; but on the basis of other work in Connecticut 

 (S), it was concluded that sulfates in the leaf are injurious to burn, aiul that 

 the ajiplic^ition of .sulfates (sulfate of potash) to the soil increases the ])er- 

 centage of sulfates in the leaf. It has been found (8), however, th.it the 

 aliility of the tobacco plant to absorb increased quantities of sulfur is \ery 



