112 



fr<)(tIioppkr blight of .suoar-cane. 



It will be seen that the three good fields have each a higher nitrogen 

 percentage than any of the damaged fields. Two of them have a higher 

 calcium oxide percentage and the same two have also a higher carbon 

 dioxide percentage than any of the damaged fields. 



The result of testing the reaction of the soil to litmus is still more 

 striking and the best soil of all is the only one that is alkaline. Both 

 the other good soils are neutral and all the acid soils are badly damaged. 

 Since the diagram was prepared further experience with field I has shown 

 it to be less damaged than first indicated, and it would be best placed 

 between E, and F. This would leave the four acid fields as the four 

 worst iittaeked and still further emphasize the gradation of the lime 

 content. 



In Fig. 29 is shown the percentage on the same 

 is an undesirable acid constituent and is increased 

 of sulphate of ammonia as manure. It will be 

 field of all has by far the highest SO3 content 

 the good soils have as high or higher than most of 

 the influence of the sulphuric acid is neutralised 

 lime, and we have previously found that the good 

 lime to do this, while most of the bad soils hfld not. 



fields of SO3 which 

 by large applications 

 seen that the worst 

 but that after this, 

 the bad. However, 

 by the presence of 

 soils had sufficient 



Fig. 29. 



F]^. "J'.t— l)ia<4iain of Sn„ percentige in the soil of the same fields. 



The other constituents of the soil, Iron, Aluminum, Magnesium 

 and Phosphates were estimated, but no significant differences could be 

 noticed. The high magnesia-lime ratio suggested by Carmody did not 

 exist in these soils. 



The soil from six fields from the estates of the Usine Ste. Madeleine 

 were analysed by the Chemist of this Company, witli results on the 

 whole confirming those given above. 



Mr. Carlee, General Manager of the Waterloo Group of Est ites, 

 which have suffered almost more severely than any others from l)light 

 infoimed nie that liis (htmist found that all their soils were acid. 



Lisciitinidv. Jt will be seen that there is a distinct evidence that 

 the froglioi)i.fcr breeds with greater freedom and that the blight is worse 

 on heavy sour soils than on light, well aerated, well limed soils. 



Sometimes a soil that is chemically suitable gets into a bad condition 

 owing to lack of cultivation. On one estate with a light soil the frog- 

 hopper attack in [1919 was confined to an area where the soil \\as 

 compact and very badly in need of cultivation. 



