PRODUCTION OF TULTP BULBS. 17 



economic loss of the bulbs left in the ground there is the added dis- 

 advantage of fouling the land. There is no crop which will foul the 

 soil worse than a bulbous one if the digging is carelessly done. The 

 undug bulbs persist. They come up as weeds in the next crop and 

 mix varieties in subsequent years. It is a good practice to go over 

 the fields about blossoming time and dig out all bulbs of the previous 

 :crop. This can be attended to at the time the general roguing occurs. 



I ANNUAL DIGGING IMPERATIVE. 



In the commercial production of tulip bulbs the writer has seen 

 fio condition under which it is economically advantageous to leave 

 the bulbs undug for two seasons. Such a practice can not be defended 

 3xcept on the basis of expediency; never on the basis of quality or 

 DFoduction. The tulip is a gross feeder, and the commercial varieties 

 ire so productive in increase of small bulbs that when not lifted 

 innually they are crowded to such an extent that they deteriorate 

 n size and are not merchantable when lifted. (PL III, Fig. 2.) 



The only condition under which it is considered at all permissible 

 jO leave tulips undug is when stocks are being worked up from small 

 sizes and no marketing is contemplated at the next digging. Even 

 n such a case, when the increased weed burden, greater danger of 

 njury from field mice, greater loss from winter heaving, and more 

 aborious cleaning are considered, it is a questionable practice. 



It is estimated that the cleaning of biennially dug bulbs takes 

 ibout three times as much labor as bulbs dug annually. The 

 iccumulation of old coats and the thick mat of roots make the clean- 

 ng a very laborious process. 



DROPPERS. 



Tulip bulbs, like many other bulbous stocks, when not planted at 

 he level which they like seek that level by a special process which 

 las been named ''dropping." (PI. XI, Figs. 3 and 4.) This signifies 

 hat in the usual artificial handling the bulbs are not planted at the 

 lepth which is natural for them. They therefore seek the level 

 rhich is best suited by di'opping or, in some instances, when planted 

 00 deep, rising to it. This shift in depth is more likely to occur 

 vdth the smaller sizes of bulbs and is more prevalent in some species 

 han in the garden varieties. 



The change of location is accomplished by a simple contrivance 

 v^hich looks exteriorly like a short stem connecting the location 

 rhere the bulb was set vnth. its newly acquhed position. In reality 

 his connection is simply a fold in the leaf stem which surrounds the 

 lew bulb. This fold lengthens, forming a tube, m the end of which 

 he new bulb develops. At times the whole original bulb drops, but 

 Host commonly some bulbs are formed in the original situation and 



102949°— 22— Bull. 1082 2 



