IRRIGATED FIELD CROPS FOR HOG PASTURING. 23 
On the basis of the results of these tests, an acre of good alfalfa 
pasture supplemented with a 2 per cent ration of barley or corn would 
carry 8 sows and from about 50 to 70 suckling spring pigs for a 
period of 60 days. During this period the pigs should gain an aver- 
age of 25 to 30 pounds each and be ready at the close of the period 
to be placed by themselves on alfalfa pasture for the remainder of the 
summer. Whether results of this character can be obtained will 
depend on the character of the pigs, the stand and growth of the 
alfalfa, and the efficiency with which the enterprise is conducted. 
EFFECT OF PASTURING ON THE ALFALFA STAND. 
It frequently becomes important for a farmer to know something 
of the effect which hog pasturing has on the stand of alfalfa. Knowl- 
edge on this question is useful when plans are being made for pastur- 
ing enterprises. At such times it is necessary to select the area to 
be used and to determine how much land is to be set aside for 
pasturing. 
The intensiveness with which irrigated alfalfa is pastured by hogs 
ranges from almost negligibly light grazing, in which a small number 
of hogs are allowed the free run of a large field of alfalfa used pri- 
marily for hay production, to the full utilization of the crop by hogs ; 
and beyond this, to extreme overgrazing, in which the grazed area 
comes to be little more than a dry lot. The very light grazing 
method may be followed in a field year after year without serious 
detriment to the stand of alfalfa, but each of the other methods 
produces marked effects on the stand of the crop. In fields which 
are grazed approximately to capacity throughout the growing season, 
the stand is frequently reduced materially in a single year. As the 
alfalfa plants disappear, weeds, especially grasses, come in, so that 
the carrying capacity gradually declines. It is seldom profitable to 
pasture a field to full capacity more than two seasons, and prefer- 
ably not more than one, as only under unusually favorable condi- 
tions will a sufficient alfalfa stand be maintained for a longer time. 
Overgrazing causes rapid deterioration of the alfalfa stand and soon 
results in almost complete displacement of the alfalfa plants by 
weeds or in total lack of plant growth. In fields which are grazed 
approximately to capacity, the stand of alfalfa can be conserved 
by practicing sound pasturing methods. The alternate-pasturing 
method is important in this connection, as it makes it possible to 
keep the hogs on one pasture while the other is being irrigated, thus 
preventing the puddling of the soil, which otherwise would occur on 
all but very light soils. It also allows the plants in each division of 
the pasture, periods of time at intervals throughout the season in 
which to recover somewhat from the effects of trampling. 
