IRRIGATED FARMING IN TWIN FALLS COUNTY, IDAHO ab 
The data presented in Table 18 are based on the results obtained 
from carefully planned experiments conducted at the Scottsbluff 
Experiment Farm, Mitchell, Nebr., from 1912 to 1923. It is believed 
that the averages for the last seven years (1917-1923) will more 
accurately measure the influence of these three factors on crop yields 
than averages for the 12-year period. The conclusion should not be 
drawn that precisely the same results would be obtained were these 
experiments duplicated in other irrigated districts. It is believed, 
however, that very similar results would be obtained in Twin Falls 
County, for the soils of the two districts are very similar. The virgin 
souls of both districts were well supplied with the essential mineral 
elements of plant food and both were low in organic matter and avail- 
able nitrogen. 
TaBLE 18.—Effect of rotation of crops, barnyard manure, and alfalfa on yield of 
irrigated crops at Scottsbluff Experiment Farm, Mitchell, Nebr., 1917-1923 
aya Seven-year average yield per acre 1917-1923 
tion (s Hotations 
Leif HAE LO EONS SES Alfalfa | Pota- Sugar 
ber Wheat | Corn hay oee Oats hects 
Short Short 
Continuous production of each crop on the | Bush: | Bush. | tons Bush. | Bush. | tons 
Saas a (leap e oeeraee 13 30 4.9 59 0 8.1 
18o|/—=Vwhesat—sugaraneets=_2 = ee et eee PODS Nee ne <M ee 8 bree eek ee 8.9 
Daeg NCA UROL Smee eee iene aes ee ee Gye ae o| ae By (a eres - 
48 | Wheat-oats—alfalfa—alfalfa_______..____________ Pihc| [eae le Qe Oe |S ane 627 | Pies if 
TGs [© OT Oni US Seemann oh ee taro ety ee, Pathe ee reel Yd epee eo | oeeh sews Aba apes oe 
SIEM OLN-Oals=Sucal DCCUS ee ee ee ee aXD) ee ere 46 9.8 
62 | Corn-oats—beets—alfalfa—alfalfa—alfalfa__________|________ 58 SAN eed te. o 65 14.6 
O78 OAS sUCAE RD CCU Swrses en sa eer ae ee Ee oe se tea | ania 52 10.0 
230 |e Oats=SuUcar Dee tsn (manne). ee a ee nn ee Se ee eee pSeeumtorasis 64 18. 2 
42 | Oats-sugar beets—alfalfa—alfalfa________________ Heh aon ee Reg eee ey PAIN \ ee Ries eee 65 16. 7 
On mROLALOGS-SlIParsDCelStee. = eee ee A ee ee | IU gh ee 10.7 
Alem Olatoes=sucambee isn Manure) s-wee eae ta een Sea ee ee BS NGO 2 eae ene 16.8 
40 | Potatoes-sugar beets—alfalfa—alfalfa____________|___-_____]_--___- 2.2 AGRA 17.9 
26H SP OLALOCS- CORES a aeee rails nr Ne See Pl see ey 1 OAS ee een |e ee ie 
DARE OLATOCS—O abe S aettedeSre ie a i a he See eS ee 123 AS nies Ses he Be 
27 | Potatoes-oats (rye plowed under) ____________- ee ee Rage pS ie, Se 162 OO nares a 
D5alseOtaloes-oabse (Manned) zass es eer sd Pid eee eb eee |Lee aac al 190 G25 |S eee = 
44 | Potatoes—oats—alfalfa—alfalfa___________________ | oe be ee (SO ae 2.6 226 (o}%e| Pe SA 
30 | Potatoes-oats-sugar beets_-______._----_------ ee na lean itcol e  en < ee 137 57 9.8 
31 | Potatoes-oats-sugar beets (manure) ___________ fee kG Mt epnn fee ees ee 189 7 16.8 
60 | Potatces—oats—beets—alfalfa—alfalfa_____________ |e ee | eee ee 3.3 226 68 14.8 
61 | Potatoes-oats-beets (manure) - alfalfa - alfalfa - | 
DIELS 2 Coase tae oe See a ee Ae ae cep he Sepa cian (are a a4 (ere 3.3 288 73 19.1 
Compiled from the 1923 annual report of James A. Holden, Superintendent of the Scottsbluff Experiment 
Farm, which is supported cooperatively by the Nebraska Agricultural Experiment Station, and the Office 
of Western Irrigation Agriculture, Bureau of Plant Industry, United States Department of Agriculture. 
Those interested in a further study of these rotations should read Nebraska Experiment Station Bulletin 190 
and United States Department of Agriculture Circulars 173 and 289. 
Table 18 shows seven-year average yields of crops grown (1) 
continuously on the same land and (2) in the respective rotations. 
Three of the 2-year and one each of the 3-year and 6-year rotations 
received manure once in the rotation period at the rate of 12 tons per 
acre. The manure was applied to the beet plat (after the beets were 
harvested) of rotation 21 and to the oat stubble of rotations 23, 25, 
31, and 61. Rye was sown in the oat stubble of rotation 27 and 
plowed under as green manure the following spring. 
Effect of rotating crops on crop yields.—Table 18 shows a higher 
yield for alfalfa when grown on the same land year after year than 
when grown in rotation with other crops. When grown continuously 
on the same land the yield was about twice as great as when the 
