24 
BULLETIN 752, U. S. DEPARTMENT OF AGRICULTURE. 
In most cases, the effects of grazing are sufficiently marked to 
require attention in connection with crop rotation. It is usually de- 
sirable to pasture the alfalfa for only one year, or at most two years, 
before the crop is to be plowed up. In this way efficient utilization 
of the pasture may be secured, and at the same time the pasturing 
will be helpful in eradicating the alfalfa in many fields in which 
the eradication of the crop is a serious problem in crop rotation. 
PASTURING SWEET CLOVER. 
On the irrigated lands, sweet clover is grown chiefly in fields where 
alfalfa fails to do well because of seepage or alkali. The species 
most commonly grown is white sweet clover (Melilotus alba). The 
crop is used chiefly for pasture, to a slight extent for hay, and some- 
times it is grown in irrigate'd districts for its seed, which usually 
can be marketed in other districts where seed production is more 
difficult. The crop is not to be regarded as a rival of alfalfa on 
ordinary irrigated lands, but its ability to grow on certain soils 
where conditions are unfavorable for alfalfa has resulted in its use 
on limited areas in irrigated districts. 
Two tests of white sweet clover as hog pasture have been made at 
the Truckee- Carson Experiment Farm. In 1916 a field of 1.25 
acres was pastured for a short period (18 days) by 18 pigs, weighing 
33 pounds each, which, in addition to the sweet clover, had a 2 per 
cent supplementary ration of barley. In 1917 nine pigs with an 
average initial weight of 59 pounds were pastured on a 0.5-acre 
field for 105 days. For the first 84 days the pigs had a 2 per cent 
ration of 3 parts barley and 1 part tankage, and during the re- 
maining 21 days a 3 per cent ration of 5 parts barley and 1 part 
tankage. The results are shown in Table XVI. 
Table XVI. — Results secured ivitli pigs on irrigated sweet-clover pasture at the 
Truckee-C arson Experiment Farm in 1916 and 1917. 
Supplementary feed. 
Barley 
Barley 3, tankage 1 
Barley 5, tankage 1 
Ra- 
tion. 
Perct. 
2 
2 
Num- 
ber of 
Pigs. 
Aver- 
initial 
weight. 
Pounds. 
33 
59 
100 
Time 
of 
test. 
Days. 
18 
84 
21 
Gain (pounds). 
Per 
acre. 
46 
754 
238 
Per 
acre 
per 
day. 
2.5 
9 
11 
Per 
Pig 
per 
day. 
0.18 
.50 
Aver- 
age 
carry- 
ing 
capac- 
ity per 
acre. 
Pounds. 
420 
1,431 
1,927 
Ration 
fed per 
100 
pounds 
of gam. 
Pounds. 
390 
308 
SftO 
In 1916, when the sweet clover was supplemented with barley, the 
pigs made very poor gains, although there was an abundance of 
clover and the pigs ate it readily. Because of the poor gains made, 
the test was discontinued at the end of an 18-day period, when the 
