20 The Colorado Experiment Station. 
did not materially increase the yield in potatoes and consequently 
that the expense was not justified. Where manure is obtainable, the 
yield of all crops for several years is increased very materially. 
Where potatoes are grown on feeding or dairy farms the manure 
has very materially increased the yearly total production per acre. 
The Breaking of Alfalfa. —Previous to 1886 it was thought 
that alfalfa could not be broken for potatoes. Up to that time the 
yield of potatoes in the Greeley district had been gradually decreas¬ 
ing; since that time much progress has been made in the methods 
of breaking and handling alfalfa land, and the yield of potatoes 
per acre has shown a great increase. The rotating or small harrow 
and the two-way plow with five and six horse hitches mark the 
highest advancement in alfalfa breaking. 
Turning Alfalfa Under. —On heavy soil, plowed and planted 
late, it is not uncommon to allow alfalfa to grow in the spring to a 
height of ten or even eighteen inches at the last before plowing. 
This alfalfa is broken by plowing not less than eight inches deep, 
with a broad or alfalfa shear longer than the furrow width and 
flattened to sever the alfalfa root before the moldboard lifts the soil. 
Heading Alfalfa is a system of great merit growing in use. 
The land is plowed in the fall or early spring as shallow as it is 
possible to cut the alfalfa roots below the crown. Then the harrow 
follows the plow and brings the severed alfalfa crowns to the sur¬ 
face so that they may be dried out and killed. After the alfalfa 
crowns are dry and dead, a second plowing is given the land, this 
time going down eight inches or so. Alfalfa roots never send up 
sprouts so that if the root is cut below the crown and the upper 
portion is killed ,no further trouble will be experienced. The great 
trouble with planting on alfalfa ground has been that after the 
alfalfa is turned over, sprouts start from the crown and continue to- 
grow during the season. See Cultivation. 
Clover and Peas used in place of alfalfa give no trouble of this 
sort but are not equal in fertilizing value, though the soil is left by 
either in very fine condition. 
Irrigating Before Plowing. —While in northern Colorado there 
is usually sufficient rain to make it possible to plow during May 
without previous irrigation, still where water is at hand, both at 
Greeley and in other parts of the state, where the rainfall is less, it 
is desirable to irrigate before or after planting, and this is best done 
before plowing. In any case the plow should be immediately fol¬ 
lowed by the harrow. 
The Smoothing Harrow. —The usual practice is to plow from 
morning until near noon, then unhitch and harrow what has been 
plowed in the forenoon before leaving the field. The same should 
be done in the afternoon. This harrowing establishes a soil mulch 
