G2 REPORT OF THE BOTANIST OF THE 
In extreme cases they use from two to three times as much 
seed as would be required on land free from smut. Finally, there 
comes a time when it is impossible to obtain a “stand” no mat- 
ter how much seed is used. | 
ROTATION OF CROPS, 
When smut becomes so troublesome that onions can no longer 
be grown with profit the land is planted to some other crop for 
two or three seasons. This treatment does not entirely rid the 
soil of smut but it reduces the amount somewhat so that for a 
few years following it is again possible to raise onions. In the 
Orange County onion district corn and potatoes are the crops 
most commonly used in such a rotation and it is there generally 
believed that corn is rather the more efficient in removing smut 
from the soil. Seeding the land down to grass for three or four 
years is also said to be somewhat beneficial. 
How long it would be necessary to withhold onions from the 
soil in order that smut might entirely die out is not known, 
but it would certainly require many years. Some observations 
made by Dr. Thaxter! in Connecticut bear on this point. A field 
which had not grown onions for twelve years was sown to onions 
in 1888 with the result that from 10 to 50 per ct. of the plants 
became affected with smut. 
While it is true that under some conditions onion smut spores 
may remain alive in the soil for a period of several years, it is 
the common experience of onion growers that even an occasional 
change of the crop for one or two years gives appreciable relief; 
and it is our belief that a systematic rotation of crops would 
very considerably reduce the amount of loss from smut. 
BURYING THE SURFACE SOIL. 
Various methods of burying the surface soil have been tried 
with varying success. One such method is deep plowing. This 
has sometimes given good results the first season but after that 
the smut is as bad as ever. Another method is to cover the field 
*Thaxter, R. Ann. Rep. Conn. Agr. Exp. Sta. for 1889: 138-139, 
