6 4 
VEGETABLE GARDENING 
be observed (Va. Truck Expt. Sta. Bui. I, p. 5): (1) 
“The plants stop growing when they should be making 
their most rapid development. In many cases they slowly 
weaken and die, while in others growth is resumed later 
in the season after rains have occurred. (2) There is a 
change of leaf color to a lighter green, especially in the 
spaces between the veins, which turn yellowish-green or 
even brown. In cabbage the margins of the leaves are 
frequently of a uniform yellow color. (3) The roots of 
the affected plants are poorly developed. Many of the 
lateral feeders are killed back repeatedly, until the root 
system becomes stubby. (4) No fungi or bacteria can 
be connected with the disease. In most cases none is 
present.” 
In the Norfolk region 3,000 pounds of fertilizer to the 
acre are often applied during the season’s operations and 
this amount is used year after year, resulting in a strongly 
acid soil. The Virginia Truck Experiment Station states 
also (Va. Truck Expt. Sta. Bui. 1, p. 5) that “acid soils 
are less favorable for the production of most truck crops 
than neutral soils. A slight amount of acidity is not 
ordinarily injurious, but examinations made at our re- 
quest by the Bureau of Soils of samples from fields where 
cabbage suffered from malnutrition, showed these soils 
to be abnormally acid, so much so that 3,500 to 6,300 
pounds of lime would be required to neutralize an acre 
to a depth of I foot. This condition is apparently the 
result of many years of intensive trucking, involving 
the use of repeated heavy applications of commercial fer- 
tilizers made up in large part of chemicals which leave 
the soil more acid. 
“Only a portion of the fertilizer applied is actually 
taken up by the plants, the remainder being left in a dif- 
ferent form, which will have an influence on the soil 
reaction. For example, sulphate of ammonia, muriate 
and sulphate of potash, and acid phosphate tend to leave 
