34 BULLETIN 1082, U. S. DEPARTMEXT OF AGEICULTLTBE. 



perfect bulb coats in the merchantable sizes when dug. The plant- 

 ing was on newly cleared cut-over Whatcom silt loam which had 

 received an application of 12 loads to the acre of half-rotted stable 

 manure in May previous to planting in August and one crop of rye 

 turned under. The size of the bulbs under these conditions was 

 very much larger than normal, measuring fully 13 centimeters as 

 against 9 or 10 centimeters under low fertility and 10 to 11 centime- 

 ters for the optimum. 



THE SOURCE OF THE FERTILITY. 



One thing above all others should be impressed upon the American 

 tulip grower, i. e., that cow dung is not the only source of fertility 

 that can safely be used; indeed, in fertile soil %vith good cover crops 

 no animal manure may be necessary. 



Stable manure from which the "fire" has gone seems to be as good 

 as any fertilizer. Sheep manure gives good results, and bone meal 

 can not be sm^passed, but it is too expensive for liberal use. 



The nature of the soil will have a great deal to do with the kind of 

 fertility demanded. On our heavy silt loams humus is needed to 

 give porosity and tilth and opportunity for percolation of water, 

 which these soils do not naturally have. 



To put the matter tersely, the crop is no more exacting in the 

 nature and origin of its required fertility than any other farm crop. 

 It demands plenty of it, but is not particular as to its source, which 

 means, as in other farming operations, that the grower will resort to 

 whatever source of fertility is available to him. Commercial fer- 

 tilizers can best be supplemented by cover crops and other means 

 of adding humus. 



DISPOSAL OF CROP RESmUES. 



As with many other horticultural crops, care should be exercised 

 in the handling of the refuse from tulip-bulb production. This 

 should not be burned or otherwise wasted, but should be handled so 

 as to avoid its use on land which is to grow tulips or other bulbs, as 

 an added precaution against the spread and accumulation of the 

 spores of fungi which cause diseases. This is a very important 

 matter and should not be overlooked. i 



This debris, made up largely of stems and leaves hoed off the beds! 

 at digging time, flowers cut off before the petals drop, old coats, and 

 imperfect, rotted, and undersized bulblets, cleaned out of the stock 

 during the time it is in the bulb house, should be composted and 

 thoroughly rotted before being used on any ground; otherwise the 

 bulbs will come up as weeds in other crops and be a source of annoy- 

 ance and loss indefinitely. There are few weeds more persistent in 

 cultivated fields than tulips which have been left undug or plowed in 

 with unrotted compost. 



