TIME OF PLOWING SMALL-GRAIN STUBBLE. 11 



from fall plowing, when wheat and corn gave higher yields from spring 

 plowing, was 1912. This was a year when the yields of oats were near 

 the maximum in that locality for the variety used — Kherson. In 

 only one year (1911) out of the six did fall plowing give the best 

 results with all three crops. This also was the year in which early 

 fall plowing gave a marked increase over late plowing with winter 

 wheat. 



The yields of winter wheat on plats A and B, presented in Table V, 

 are of interest. Three years out of the six one plat was plowed earlier 

 than the other. The condition of the surface of the plats during the 

 winter was the same, both being devoid of stubble and equally level. 



The only important difference in treatment was the time of plowing. 

 In all three instances the higher yields have been on the earlier plow- 

 ing. The only marked difference, however, was in 1911, when the 

 earlier plowing had been done immediately after heavy rains and a 

 large growth of weeds occurred on the later plowed plat before it was 

 plowed. In the three years when there was no difference in time of 

 plowing there was no difference greater than 1.3 bushels in yields. 

 While this was a difference of more than 60 per cent, it will be noted 

 that both plats were practically failures in that year (1913). In the 

 six years the only marked difference in yields was in 1911, when the 

 plowing was done 22 days earlier on plat B than on plat A and plat 

 B yielded 5.1 bushels more than plat A. Except when early plow- 

 ing had stored moisture by stopping weed growth, there was no 

 marked difference in yields. The late fall plowing usually lost 

 available moisture by weed growth, which was not offset by a greater 

 winter accumulation, as in spring plowing. 



In studying each year separately it is necessary to consider the 

 precipitation. Data on the moisture content of the soil in the fall 

 and spring and at harvest time will aid in giving an idea of the relative 

 importance of fall and winter precipitation and the amount used by 

 the crop. 



Figure 1 shows that in the fall of 1908, up to which time the plats 

 had had uniform treatment, there was no moisture in the soil available 

 to plants. August and September were very dry and plowing was 

 not done until the weeds had been killed by frost. While there was 

 heavy precipitation in November, 1908, and in March, 1909, the 

 increase in moisture run tent was practically the same, the third foot 

 of both plate being partially filled. Plat A gave a yield of 14.3 

 bushels, and there was still some moisture available at the time of 

 harvest. The, greater number of weeds growing with the wheat in 

 plat B probablj accounts for the greater loss of moisture and the 

 smaller yield. This statement is home out, by the yields of eorn, 

 whieh woe practically the same from both the spring and the full 



