38 BULLETIN 1173, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE 20.—Average yields of winter and spring wheat at Moro, Oreg., grown after fallow 
under three methods of cultivation in the 9-year period from 1913 to 1921, inclusive. 
Yields per acre (bushels). 
Crop and date of plowing. | 
. No culti-| One har- pen 
vation. | rowing. Gan, 
Winter wheat: 
Spring plowing— 
Aprill(early:) 3... So2 sss acta eee see RN a er SAO ea 26.6 21.2 31.9 
ot May si(Wateyis 24s e cin of pee cai a clare ee eee eee eee 25.9 26. 2 PA Pet 
Summer plowing— be 
JUNG 1 (@arly,).c.-susacieas ose ose ee ee oe ene nee eee | 22.4 22.6 22.9 
Fall plowing— ; | 
Marly cs SOR Wa See eer oe ene reverts kee bree ae em Weg opin 24.9 29.5 
1: en eg ete Ps ps eR eae Sona soe ani (eres eae pee 26525} 26.3 
Spring wheat: 
Spring plowing— 
Shallow: Fi cee ease tes Be ee SR hy ee eee ee ee 19.6 19.5 20. 6 
Deep...--. a Stetete Sake msn Sepia ee es broke ke GPR aie > Loe Seeger a ee 20.2 20.6 20.7 
K : 
Fic. 20.—Summer fallow in excellent condition at the Sherman County Branch Station, Moro, Oreg. 
Note the fine clods on the surface and the complete absence of weeds. Rotation and tillage plats are 
shown in the background. 
The yields shown in Table 20 under the heading “ Frequent 
cultivation”? were obtained from fallow harrowed twice immediately 
after plowing, harrowed again about three weeks later or when weeds 
had started, and weeded with a rod weeder two or three times during 
the summer. On the land plowed in the fall and on that plowed on 
April 1 Russian thistles were troublesome on the plats given no cul- 
tivation and those harrowed only once after plowing. These weeds 
were allowed to grow on these plats until they attained considerable 
size, but they were hoed off each year before maturing seed. This 
weed growth undoubtedly was one cause of the reduced yields on 
these plats. On the land plowed on May 1 there usually were very 
few weeds on the fallow and not enough in any year to be a factor in 
reducing wheat yields. On land plowed on June 1 no weeds were 
able to grow, on account of the dry soil. 
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