WHEAT PRODUCTION ON DRY LANDS. 43 
Total straw growth has always been greater on the plats with 
higher nitrate content. At Moro on the June-plowed plats the ratio 
of grain to straw was about 1 to 1.5, while on the April-plowed plats 
the ratio of grain to straw was, on the average, about 1 to 2.5. Asa 
result of this greater straw growth, due to the fact that the heavier 
vegetation more quickly depletes soil moisture, there was a tendency 
during dry seasons for the crop to burn more readily on the early 
well-tilled plowing, and also a tendency for grain to be lower in 
bushel weight because of maturity being hastened. The smaller 
vegetative growth of the crop on the late-plowed or insufficiently 
cultivated fallow, on the other hand, did not so rapidly deplete soil 
moisture, the crop ripened more slowly during dry weather, and as a 
result produced larger, heavier grain. 
The quality of the grain produced varied not only in weight but 
alsoin composition. ‘That produced on the poor fallow, low in nitrate 
content, was large and plump with a Imgher percentage of yellow 
berry, while that produced on the well-tilled fallow, high in nitrate 
content, had a tendency to be somewhat lower in bushel weight, and 
even if of equal weight had a much smaller percentage of yellow-berry 
kernels. Analyses showed that the grain from the well-tilled fallow 
was higher in nitrogen content, and baking tests showed it to be ~ 
superior in baking quality to that from the poorer fallow. 
Considerable moisture is required in the fall to make conditions fit 
for germination in ground plowed dry or in that from which moisture 
has been removed by weeds growing on the summer fallow. Ground 
plowed early in the spring and properly cultivated during the fallow 
season will require materially less moisture to make a good seed bed. 
Much heavier seeding is required to secure a good stand of winter 
wheat on poorly prepared fallow than on that properly handled. 
Thinner stands on well-tilled early fallow are compensated by greater 
tillering, due to the more abundant supply of nitrate nitrogen. On 
the late-plowed or poorly tilled fallow thin stands generally will tend 
to reduce yields, because there is not enough available nitrogen to 
promote tillering. This latter statement, of course, applies only 
during seasons when moisture is not entirely the limiting factor. 
An abundant supply of nitrate nitrogen in the soil at the end of the 
year of fallow is a very important factor in securing a vigorous growth 
of winter wheat in the fall, and undoubtedly the plants growing on 
well-tilled summer fallow are much less liable to winterkill than those 
on more poorly tilled ground. 
Crop yields are the net result of the operation of all soil factors and 
are limited by one or another of these factors as it may be propor- 
tionately less favorable than the others. Under dry farming, 
moisture usually is the limiting factor, but the degree of its impor- 
tance in this respect varies considerably. Under extreme conditions 
moisture alone may determine crop yield, but as rainfall becomes more 
abundant it assumes a place second in importance to available plant 
food. Between these extremes there is every gradation in the relative 
_ importance of these two factors, this gradation extending even to 
individual localities and varying there with seasonal conditions from 
year to year. 
_ In the drier districts it may be necessary to think only of moisture 
in tillage operations, leaving the other factors to care for themselves, 
