The Storage and Use of Soil Moisture 
57 
had it produced a crop. Cases similar to this are sometimes 
seen on farms where a tract is being summer tilled. The land 
is kept clean and water stored during a portion of the season. 
Then other work becomes urgent and the summer tilling is neg- 
lected. The weeds come on, using a part or all of the accumu- 
lated water, and the previous labor is largely lost. 
The work shown in Table 23 is a continuation of that shown 
in Table 22 for 1907, on the effect of weeds. The same plats 
were used. There is a difference of almost two per cent of water 
at the first sampling. The plat that is kept cultivated does not 
accumulate any additional water during the season, as it is 
already filled with water. Instead of being summer tilled it 
should have been cropped. The plat that was allowed to become 
weedy lost moisture thruout the season, and was as dry at the 
time of small grain harvest as it would have been if it had been 
cropped. The plat that was kept clean contained more than five 
inches more water than the plat which grew the weeds. 
Table 24. — Effect of weeds on soil 'moisture, 1911. 
PER CENT MOISTURE IN THE SOIL. 
Depth 
Weedy 
No weeds 
Fret 
1 
8.7 
14.7 
2 
8.5 
10.1 
3 
7.0 
7.2 
8.1 
10.7 
The data given in Table 24 were obtained from a field which 
was being plowed May 20, 1911. Tt was noticed that where 
weeds were growing the soil was very dry and turned over lumpy 
and hard. Where there were no weeds, the soil was in good 
condition to plow and work down for a seed bed. Samples were 
obtained and the difference in the moisture content ascertained. 
The weeds were mainly Russian thistles and were small, averag- 
ing only two to three inches high. Their growth, however, had 
consumed over an inch of water, mainly from the first foot of 
soil. Had the land been worked and these weeds killed early in 
the season, this water would have been saved for the use of the 
crop and less labor required to prepare a good seed bed. Similar 
conditions are sometimes seen during dry seasons in fields which 
