12i MASS. EXPERIMENT STATION BUELETIN 276 



drained, and under tliese conditions of excessive rainfall tobacco grew so 

 poorly on all jtlots that tlie effects of the several soil treatments on growth 

 were largely obscured, '^'ields on all plots, limed or not limed, were the low- 

 est they had ever been, and topography of the field had for the first and only 

 time some effect on the growth of tobacco; in thirteen out of seventeen pairs 

 of duplicate plot treatments, the plots in the lower half of the field yielded 

 less than the plots in the higher half of the field. 



Limed plots yielded 23 per cent less in 1929 and 25 per cent less in 1930 

 tiian did plots not limed. Thus, seven years after liming, the soil was still 

 sufficiently favorable to Thielav'm basicola, as evidenced by yields (and infec- 

 tion of roots), to pre\ent the profitable growing of tobacco on limed ])l()ts. 

 But the loss caused by lime, applied in 1923, decreased from 45 per cent in 

 llfi", to 23 per cent in 1929. 



On QiMlity and Burn of Tobacco 



The index of quality used for jjurposes of comj^jarison is the percentage 

 of leaf of the grades lights, mediums, and seconds in the tobacco from each 

 plot. 



In general, lower yields on limed plots were associated with poorer qual- 

 ity. In 192() (Table 11) 48 per cent (mean for duplicate plots 5 and 17) of 

 the tobacco from plots without lime was mediums and seconds, and only 26 

 per cent (mean for duplicate plots 12 and 24) of the tobacco from limed plots 

 was so classed. Again in 1927 (Table 12), there was a higher percentage of 

 mediums and seconds from plots not limed than from limed plots. But in 

 1928, 1929, and 1930 (Tables 13-15), with smaller differences in yield between 

 limed and unlimed plots than in earlier years, the quality of tobacco on limed 

 plots was not definitely inferior to the quality of tobacco on plots not limed. 



In addition to the crops of the years discussed in this paper, the burn 

 of the tobacco of the crops of 1924 and 1925 (described in an earlier report 

 (5) from plots with and without lime was tested.^ 



In 1924, the first year after the last application of lime, the fire-holding 

 capacity of both darks and seconds from limed plots was considerably better 

 than that of corresponding leaves from plots not limed, as may be seen by 

 reference to Table 4. 



Taki-e 4. — Fire-holding capacity of tobacco, crop of 1924. 



Percentage of tests 



in which the burn was : 



Grade of leaf Soil treatment 



Seconds- 

 Darks 



Good Fair Poor 



Per cetif Prr rent Percent 



f Limed plots 56 37 7 

 " "I Plots not limed 25 42 33 



f Limed plots 30 50 20 

 I Plots not limed 54 46 



In five out of six com})arisons made in the crop of 1925, the fire-holding 

 capacity of the seconds was better without lime than with it. In six out of 

 nine comparisons of the darks in this crop, the fire-holding capacity was as 



^ The burn of the crop of 1924 was tested by Walter Edwards and that of 1925 

 was tested by J. P. Jones, formerly Research Professor of Agronomy in ifassachusetts 

 Agricultural Kxperiment Statioa. 



