8 



BULLETIN 79, IT. S. DEPARTMENT OP AGRICULTURE. 



ash content and the ratio of leaf web to rib in the uncured leaves, as 

 well as the detailed analyses later reported, show conclusively that 

 the original samples used for stalk curing were very similar to the 

 corresponding samples used in curing by priming. 



The results of the three-year experiment are set forth in detail in 

 section B of Table I. It will be seen at a glance that the loss in weight 

 of the whole leaf in curing on the stalk is far greater than when the 

 leaves are separated from the stalks. The figures run from about 25 to 

 30 per cent, or approximately double those for curing the picked leaves. 

 In the 1908 sample the total loss in weight would have been somewhat 

 greater had the stems been given sufficient time for complete curing. 

 The loss in weight in stalk curing is greater in both leaf web and rib 

 than when the picked leaves are cured. It will be seen that the 

 apparent loss in pure ash is positive and marked in all cases in both 

 the leaf web and the ribs, showing conclusively that a portion of the 

 ash passes into the stalk during the curing. 



EFFECT OF SPLITTING THE STALK ON THE LOSS OF WEIGHT IN AIR 



CURING. 



In some tobacco districts the stalk is split longitudinally from the 

 top down the greater part of its length at the time the plant is 

 harvested. Under these conditions the stalk can not remain alive 

 in the barn as long as when it is merely severed from the rootstock, 

 and it is to be expected that the phenomenon of translocation would 

 be less important. A special experiment was carried out to secure 

 information on this point. 



Two similar lots of 10 plants each were selected, and the stalks of 

 one lot were split in the manner followed by growers. Each alternate 

 leaf was picked from the plants in both lots, and the two lots of leaves 

 thus obtained were cured separately. The leaves remaining on the 

 stalks were cured under the same conditions as the primed leaves. 

 When the curing was complete the dry weights were obtained as in 

 the preceding experiments. At that time the unsplit stalks were 

 still green, while the split stalks had largely dried out. 



Table II. — Loss of dry weight in air curing as affected by splitting the stalk in harvesting. 





Stalks split in harvesting. 



Stalks not split in harvesting. 



Air-cured leaves. 



Leaf 

 web. 



Stems. 



Whole 

 leaf. 



Leaf 

 web. 



Stems. 



Whole 

 leaf. 



Weight of 50 leaves: 



Cured on stalk grams. . 



Difference in loss of weight between stalk 

 curing and curing picked leaves, per 



177.9 

 219.5 



18.9 



71.8 

 73 



70.1 

 81.1 



13.6 



28.2 



27 



248 

 300.6 



17.4 



176.5 

 227 



22.2 



72.1 

 72.8 



68.3 

 84.6 



19.3 



27.9 

 27.2 



244.8 

 311.6 



21.4 



Leaves consisted of: 













