TIME OP PLOWING SMALL-GBAIN STUBBLE. 13 
ing and spring plowing were nearly equal. At harvest there was a 
small amount of moisture in plat A to a depth of 6 feet, while that 
in plat B had been exhausted. 
The remainder of the moisture in plat A was used by weeds, and 
at the time plat B was plowed, September 18, 1912, the moisture in 
both plats was equal. In the spring of 1913 the first determination 
showed there had been a slight increase in the water content of plat 
A to a depth of 3 feet, while there had been an increase in only the 
first foot of plat B. The water in plat B was so nearly exhausted 
by the first week in June that the crop was burned beyond recovery, 
while plat A had water enough, supplemented with a light precipita- 
tion, to produce 4.8 bushels of wheat. The yields from all plats were 
very low, but the average yield was higher for all three crops on 
spring plowing. 
The light precipitation of August and September, 1913, did not put 
the soil in condition for plowing until October 14. There was very 
little weed growth in the fall and the sampling of October 2 shows 
very little stored water. The water content of plat A in the spring 
was twice as great as that of plat B, but neither had an appreciable 
amount of available water below the second foot. While there was 
but a small difference in the moisture content of the two plats, the 
yield of grain from plat B was only 55 per cent of that from plat A. 
The yield of straw was the same from each. The slight difference in 
water content in favor of plat A, with the smaller number of weeds 
in the grain and a normal precipitation during the growing season, 
had enabled it to produce a good crop of grain, while plat B had 
dried up before maturing. 
SUMMARY. 
The average yields from spring and from fall plowing show that 
the blind following of a rule prescribing any particular time of plow- 
ing might cause a reduction as often as it does an increase in the 
yields of the three spring crops of wheat, oats, and corn. The very 
small difference in yield each year from plats plowed at the same 
time, when compared with the greater difference from plats plowed 
at different times, indicates that the time of plowing is one of the 
most important of the controllable factors in crop production. 
The great variation in the time and amount of precipitation is the 
important climatic characteristic of this region in eastern Colorado 
that must be kept constantly in mind when considering the time of 
plowing. No dependence can be placed on a heavy precipitation in 
August and September, yet it frequently occurs. When there is such 
precipitation, measures should be taken to conserve it. Weeds being 
the important factor in its dissipation, cultivation to destroy them 
should be given as soon as possible after the occurrence of rains in 
