46 
Research Bulletin No. 5 
in this tesi was to check the effect of the neglect of cultivation 
with the effect of growing weeds. It is seen from the table that 
each of the plats contained nearly the same amount of water 
at the beginning of the test. No great variation is seen until 
June 29. It is noticed that the difference in water content be- 
tween the thoroly tilled plat and the weedy plat is much greater 
than the difference between the thoroly tilled plat and the plat 
not cultivated but kept free of weeds. There was several times 
as much water lost from the weedy plat as from the one where 
only cultivation was lacking. 
It must be borne in mind that this work was started with a 
soil almost filled with water, and carried on during a season of 
heavy rainfall. There was no prolonged or extremely dry spell 
of weather this season. The results apply to the loss of water 
after it has been gotten into the soil, and show that on this type 
of soil under a normal rate of evaporation growing weeds cause 
a much greater loss of water from the soil than surface evapora- 
tion. We cannot say what the results would have been if we had 
started with a soil filled with water and had run the test thru a 
very dry season. It is probable tho that the loss from an uncul- 
tivated surface would be much greater. The results given in 
Table 14 show that during a less favorable season and starting 
with a soil comparatively dry below the second foot, there is 
much less water retained from the rains where the surface is not 
cultivated than is retained by the cultivated surface, which fur- 
ther proves that from the viewpoint of storing water a cultivated 
surface is essential. 
ARTIFICIAL MULCHES. 
It is a rather common practice to use artificial mulches among 
shrubs, small fruit, and in some cases vegetables. The Station 
has done some work to determine the value of artificial mulches 
from the viewpoint of catching and holding the water that falls. 
These mulches are usually composed of old hay, straw, or 
manure. From the viewpoint of retaining water, they are most 
efficient and have a practical application. Wherever it is desired 
to grow shrubs, ornamentals, or small fruit, the mulch can be 
used for retaining water. Against its efficiency in holding water 
the opinion is sometimes advanced that it forms a harboring 
place for injurious insects. We have no data on the latter point. 
In the following tables the effect of the mulch on the water con- 
tent of the soil is shown. 
We are offering two tables on the effect of mulch. A number 
