42 BULLETIN 140, U. S. DEPARTMENT OF AGRICULTURE. 
importance, and this phase of adaptation has been carried even to 
the point of breeding tobacco to suit local soil conditions. 
The effect of soil influence on the quality and keeping characteris- 
tics of the particular variety of onion, Yellow Danvers, which has 
made the Connecticut Valley one of the leading centers in the United 
States in the production of this crop, also illustrates the principle 
of soil adaptation to specific variety. Grown on the sandy loam 
above referred to the bulbs are hard, fine-textured, and unexcelled in 
quality. When grown on the loam of the same series the texture 
of the onion is coarser, the necks do not cure down as well, and the 
bulbs are softer; because of these characteristics the latter are less 
desirable for storage purposes, and their culinary quality is inferior. 
The factor of edibility .is not of sufficient importance to make any 
general difference in the selling price, but the hard onions are always 
sought by buyers for storage purposes, and on this account bring the 
top quotation when the market is dull, and sometimes even an ad- 
vance price. When the crop moves slowly in the fall, moreover, 
the growers who store any part of their crop always select first for 
this purpose the hard onions. In actual practice this means those 
onions grown on the sandy loam soil. On heavier soils, with higher 
moisture content, the quality of the bulbs is correspondingly poorer. 
In southwest Minnesota a shallow glacial valley some 3 miles wide 
divides the upland prairie which extends for many miles in a trans- 
verse direction. The irregular valley walls range in height from 
15 to 30 feet or in some cases a little more. The valley soil is a clay 
loam, richly charged with humus. It is suited to grass and other 
forage crops, but wheat runs heavily to straw, none of the grain 
grading above No. 2, while much of it is No. 3. Wheat from the 
gray clay loam to the west of the valley, where the growth of straw 
and the filling of the heads is well balanced, gives a high percentage 
of No. 1 grain. Grown on the brown loam east of the valley, the 
grade is about half No. 1 and half No. 2. These lands have been 
farmed only 30 to 40 years, hence they have never been dressed to 
any appreciable extent with yard manure or commercial fertilizers. 
The superintendent of the elevator at the county seat where most of 
the grain is sold claims that he can tell on which <3f these three soil 
types a farmer, unknown to him, lives by the way his wheat grades. 
However this may be, the influence of the soil on the quality of the 
same varieties of grain is effectively shown by the money returns at 
the elevator. 
In southeast Michigan the profit from- sugar beets grown for the 
factory follows closely the character of the soil upon which the 
beets are grown. Beets from the light sandy soils have a high sugar 
content, with a high coefficient of purity, but the tonnage is relatively 
small. Moist, rich clay loams and loams yield a heavy tonnage, but 
