CHAPTER XXI 
SYSTEMS OF CROPPING 
Necessity of intensive methods.—The student who has 
followed the discussions of previous chapters has doubt- 
less observed that vegetable forcing is a most intensive 
type of horticulture. It calls for large expenditures of 
capital and labor upon relatively small areas. The invest- 
ment on one acre of land may be greater than on a farm 
of 100 acres. 
The first cost of the land is a small factor. But the 
range of houses with its equipment of boilers, heating 
pipes, water lines, packing room, etc., may represent 
thousands of dollars, though it may be a mere garden 
patch in size. Furthermore, we must bear in mind that 
the cropping operations themselves are far more expen- 
sive than similar lines of work in the field or garden. Every 
need of the crop must be met by the employment of arti- 
ficial methods. Large amounts of fuel must be consumed_ 
annually. Even the water must frequentl: be paid for, 
in addition to the labor involved in applying it. Tem- 
peratures must be regulated and the ventilators operated 
as often as may be necessary. It is necessary to maintain 
the highest fertility of the soil, and sometimes to sterilize 
it in order to prevent diseases or insects pests from gain- 
ing the upper hand. Some of the vegetables require 
special attention in the way of pruning, training, pollinat- 
ing and spraying. The houses require more or less atten- 
tion annually in order to keep them in good repair, and the 
interest on the investment and the depreciation in the 
value of the range and equipment must also have con- 
sideration. 
An enumeration of the foregoing factors is given not 
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