2 BULLETIN 1424, U. S. DEPARTMENT OF AGRICULTURE 
If the hay is raked into windrows as soon as the leaves are well wilted and then 
put into tall, narrow shocks and allowed to cure out slowly and thoroughly so 
that the leaves will be kept alive to give off the moisture of the stems by trans- 
piration, the farmer can more easily determine when the hay is thoroughly cured 
than if curing is done mostly in the swath or windrow. — McClure (3, p. 10). 
As soon as the plants are cut the leaves lose water and draw on the stems 
for more. * * * If they dry too fast * * * the leaves are killed pre- 
maturelv; they stop pumping water out of the stems * * *. — Pieters (6, 
p. U). 
After the plants are cut, while the leaves are wilted but before they are too 
dry, the leaves draw moisture from the stems of the plant. As soon as the leaves 
become dry they cease drawing moisture from the stem. — Waldron (9, p. 370). 
If hay is raked into the windrows after partially curing in the swath but before 
any of the leaves have become dry, a large proportion of the hay will be pro- 
tected from the direct rays of the sun and the curing will take place evenly by 
transpiration of water from the leaves. — Roberts and Kinney (8, p. 15). 
It is partly on the assumption that leaves do continue to pump 
moisture from stems even after the plants are cut that curing in the 
windrow or cock has been so commonly advocated. It is generally 
recognized that hay cured in this way retains more of its leaves, 
thereby increasing its feeding value, but so far as can be ascertained 
no experiments have been conducted to determine whether any 
appreciable quantity of water passes off from the stems through the 
leaves after a crop is harvested. 
With this in mind, some simple tests were begun in 1924 and 
continued in 1925. These tests were conducted at Redfield, S. Dak., 
Bard, Calif., Rosslyn, Va., near Washington, D. C, and North Bidge- 
ville, Ohio. Samples of alfalfa were taken and weighed immediately. 
One or more of these were left to cure in the natural condition — that 
is, with the leaves on — while the leaves were picked from others by 
hand. Weights of the various lots were taken at the same time in 
all cases, but the intervals between the weighing periods were more 
or less irregular. The weighings were continued until the weights 
had become stationary or practically so. 
TESTS AT REDFIELD, S. DAK. 
The most extensive and complete tests along this line were con- 
ducted at the Redfield field station, Redfield, S. Dak., in 1925. Tests 
were made in triplicate, the various samples being allowed to dry in 
the seed house. Three 100-gram samples were cured in the natural 
condition; that is, with the leaves attached to the stems. From 
three other 100-gram lots the leaves with the petioles were picked by 
hand as quickly as possible, after which the stems and leaves were 
weighed separately. Leaves were picked of! other lots at the end 
of 4, 7 }/2, 25, 31 J^, 48 J^ hours and daily thereafter with one exception. 
Up to the time the leaves were removed the various samples had been 
allowed to cure in the natural condition. Subsequent to the initial 
weighing the stems and leaves were weighed separately. As plants 
lose moisture most rapidly during the first few hours after cutting, 
weights were taken at rather short intervals the first day, twice the 
second day, and once every 24 hours thereafter. These losses, which 
in all cases are the averages of three samples, are shown in Tables 1 
and 2. 
In Table 1, column 1 shows the percentage losses in alfalfa cured 
with the leaves attached, whereas column 2 shows percentage losses with 
leaves removed. In all other columns the first figures (those in italics) 
