WHEAT PRODUCTION ON DRY LANDS. 15 
SPRING DISKING. 
Experiments to determine the value of disking in the spring prior 
to plowing also were conducted at Moro and Lind. The results 
obtained from these experiments are presented in Table 7 and are 
shown graphically in Figures 11, 12, and 13. It will be noted from 
this table that spring disking has significantly increased wheat yields 
~ at Moro when the plowing was done as late as June 1. With plowing 
done in April and early in May there seems to be no advantage in 
spring disking. 
Taste 7.—Annual and average yields of Turkey winter wheat on land disked and not 
disked before plowing at different times in the spring at Moro, Oreg., from 1913 to 1921, 
_ end at Lind, Wash., from 1918 to 1921. 
Yield per acre (bushels). 
a... »S 
Seth: 0 etter eer tent EF TRA eee inated apn 
- j ‘ ia ‘ 7 Lo 
ney ' P 
Station, date of plowing, and treatment |—_——________ 
before plowing. | Aver- 
1913 | 1914 | 1915 | 1916 | 1917 | 1918 | 1919 | 1920 | 1921 
age 
MORO, OREG. 
Plowed early in April: 
oS a ae eee eee 25.1 | 26.9 | 26.3-| 41.3 25.0 | 22.3 | 38.5 | 29.7 | 3L3 | 29.6 
L. To TET SS ee oe os ee 30.0 | 32.0 | 26.4 | 45.7 | 25.7 | 23.5 | 39.7 | 32.8 | 31.7 | 31.9 
Plowed early in May: 
UE ee ee ee 18.5 | 27.8 | 27.5 | 35.1 | 22.3 | 19.2 | 35.3 | 25.3 | 36.7 | 27.5 
1. ALIS Se See eee 19.0 | 27.0 | 24.7 | 38.0 | 24.7 | 24.7 | 30.0 | 31.0 | 29.8} 27.7 
Plowed early in June: 
SEE 2 8 SE ee ae en 23.0 | 27.7 | 23.9 | 34.3 | 23:1 | 20.3 | 32.3 | 29.0 | 32.5-| 27.3 
1 TLDS 2. es 7.3 | 21.6 | 20.5 | 34.8 | 24.7 | 26.0 | 19.5 | 26.5 | 25 22.9 
| } 
LIND, WASH. 
Plowed early in March: . 
2 p44 72S =: See oe eee pee eee ee 6.1} 412) 37-133.) ~9-8 
oO: (DEE i 2: se: ee ee ees eel eee ae eee Ce seen Pee 0:2°) 125) |*-9.84 15. 7 11.0 
Plowed in mid-April: 
TREGL is io LS ee OS ee ee eee 529) |) 12: 0] ¥&14°15.0 10.2 
“OT? LEP. 2 ee ae ee es Ee ee ees ae ee 6.0 | 140]. 9.2 | 16.3 11.4 
Plowed early in June: 
masked twice (Mar. £and Apr. 10). |. 2... -|...=..|-...-.|-.2.<- kag ae 5.9. | 1493 |. 9.2) 1327 ja 10.8 
2 DEL TEE) (TTS! aps aS eae Ea es ees ee ea eee 5.8 | 13:3 1. 820,320 atone 
3.3 | 11.3] 5.0 | 12.3 8.5 
a a Ee ee eee SS Ee |---2=-|---2--].-2---]------ 
BURNING STUBBLE. 
In certain sections of heavy rainfall in the eastern parts of Oregon 
and Washington, the practice of burning the stubble before plowing 
is quite generally followed by farmers. The stubble usually is 
_ burned in the early spring, though some farmers burn it late in the 
fall. When wheat is harvested with the combined harvester, as is 
the custom in eastern Oregon and eastern Washington, a large part 
of the crop growth is left on the land in the form of stubble. Most 
of the straw which goes through the machine also is left in the field 
in windrows or piles, to be burned or plowed under. Frequently 
_ the stubble and straw are so heavy that much difficulty is experi- 
enced in cultivating fallow after they are turned under. 
Sufficient experimental data are not available to determine the 
actual effect on the yield of wheat of burning the stubble. The 
only experimental data yet available are from results obtained at 
the Nephi Substation, where this experiment has been in progress 
during the six years from 1916 to 1921, inclusive. 
