18 BULLETIN 595, U. S. DEPARTMENT OF AGRICULTURE. 
this method, the only other method showing a profit is early fall 
plowing, with a nominal one of $0.05 per acre. Green manuring and 
late fall plowing show losses of $3.25 and $1.87 per acre, respectively. 
The loss shown for listing is for one year, 1916, when none of the 
methods except disked corn ground produced a profit. 
NORTH PLATTE FIELD STATION. 
The work here presented is conducted on the table-land of the 
North Platte Field Station. The soil is of the type generally known as 
loess. With the exception of the humus accumulated near the surface, 
it is practically uniform to great depths. The storage and use of water 
is unlimited by the depth of the soil or any peculiarities in it. The 
development of roots is limited only by the physiological character 
of the crops grown and the available moisture. It is a soil on which 
a maximum of results from tillage methods would be expected. 
The highest average yield of winter wheat at the North Platte 
station has been 22.6 bushels per acre, obtained after rye as a green- 
manure crop, a yield of 0.5 bushel higher than that on disked corn 
ground, which shows the next highest average. The yields after peas 
have averaged 2.3 bushels less than the yields after rye. The yields 
on disked ground after potatoes, winter wheat, and oats have aver- 
aged 3.7, 7.5, and 9 bushels less, respectively, than on disked corn 
eround. The yields from summer tillage have averaged higher than 
from any of the continuous cropping methods except disked corn 
ground. Early fall plowing has given higher yields than late fall 
plowing, and late fall plowing of winter-wheat stubble has given 
higher yield than disking winter-wheat stubble. Disked oat ground 
has given the lowest average yield. The most profitable method has 
been disked corn ground, with disked potato ground next. Disking 
as compared with summer tillage, green manuring, or plowing fol- 
lowing the same crop has been the more profitable method except 
where the crop followed oats. Plowing oat stubble has given a 
sufficiently higher yield than disking the same to make it the more 
profitable method. On land continuously cropped to winter wheat 
the average profit from early fall plowing has been the same as from 
late fall plowing. The profit from summer tillage has been much 
ereater than from green manuring, but less than from any method 
producing a crop each year. (Table X.) 
Winter wheat was grown in field tests at the station during the 
years 1907 to 1911, inclusive, on land summer tilled the year preceding 
the wheat crop and on land continuously cropped to winter wheat 
and early fall plowed. The figures have been published in Nebraska 
Bulletins Nos. 118 and 135 and in United States Department of Agri- 
culture Bulletin No. 268, entitled ‘“‘Crop Production in the Great 
Plains Area.” These figures, averaged with the results obtained on 
Oe oa eo Reese Ae NE Se Ptincs 
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