142 EXPERIMENT STATION RECORD. 



ripen before frost. The amount of available plant food in the soil and the condi- 

 tions of the weather must also be considered. It is therefore impossible to set 

 any fixed rule for height of topping tobacco, and the grower must depend upon 

 his own judgment. 



" We can, however, safely draw these conclusions from these experiments : 

 Under favorable conditions of soil fertility, weather, and time for topping, and 

 with a reasonably good strain of tobacco, it is advisable to top high when the 

 question of weight per acre is the chief controlling factor. We must, however, 

 bear in mind that by increasing the number of leaves on a plant we decrease the 

 amount of sunshine that can reach the lower leaves, which means that we shall 

 obtain a leaf thinner in body and also that we shall decrease the relative size 

 of the leaves. Also, by closer planting, we may increase the weight, but we 

 l>roduce a leaf slightly thinner in body and not so uniform in color. By closer 

 planting we also increase the difficulty of cultivation and suckering. The fore- 

 going remarks are based, it is to be remembi'red, upon exi^eriments with plants 

 of exceptionally erect habit at the time of topping." 



Notes from a reconnoissance survey on the tobacco industry in Clinton County 

 are also given. 



Tobacco experiments, W. Frear, E. K. Hkshman, O. Olson, and H. R. 

 Kraybill (rcnnsylvania Sta. Rpt. 1913, pp. 171-200, pis. 37). — This reports 

 tobacco experiments conducted by the station in cooperation with the I>ancaster 

 and Clinton counties' tol)acco growers' societies and the U. S. Department of 

 Agriculture, and continuing work noted above. 



These experiments include work to determine the yield values of selected 

 filler strains of Broadleaf tobacco, yield of different filler varieties, yield and 

 quality of binder and wrapper tobacco varieties, influence of different conditions 

 of topping and planting upon filler tobacco yields, influence of topping tobacco 

 plants upon their later development, influence of suckering upon the development 

 of the tobacco plant, influence of additions of mineral fertilizers to barnyard 

 manure upon the yield of filler tobacco, and studies to determine the eff(>ct of 

 steam sterilization of tobacco seed beds. Data show score card values of varie- 

 ties of filler tobacco. 



Data from the Lancaster County tests show that low topping resulted in a 

 lower yield, and that with higii topping there was little difference betwoon 

 normal (28 by 42 in.) and close (28 by 36 in.) plantings. 



Data from a study of the influence of the time of topping iipon the distance 

 between the leaves on the stalk " indicate that the total length of stem continues 

 to increase in the untopped plant, at least until the middle leaves are ripe. The 

 distribution of this gro^vth among the internodes is not determined by these 

 measurements, but the total rate decreases rapidly. Topping does not instantly 

 arrest the stem elongation but greatly decreases its rate. Most plants show no 

 growth in the stem length after being topped when the first flower is half devel- 

 oped. There is a distinct increase in the leaf interval between the time of ap- 

 pearance of the first bud and that when the first flower is just in bloom. This 

 increase from August 19 to 26 amounted, in the plants and growth Indications 

 hei*e observed, to an average of 0.13 of an inch between adjacent leaves. This 

 increase may have affectetl the upper internodes alone. The practical importance 

 of the difference may be judged from the average internode lengths at the dates 

 mentioned (14 internodes being here concerned), namely, August 19, 1.16 in.; 

 August. 29, 1.59." 



The usual method of suckering showed a plat yield of 1. 78.^1 lbs. of strippetl 

 leaf as against 1,230 lbs. from a plat not suckered. An increase in yield of 129 

 lbs. of cured leaf per acre is noted as the result of the addition of 10 tons of 



