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Bad bi PEN:: OFT ELE

USDEPARTMENT OPAGRICULTURE &

(BA
No. 10

Contribution from Office of Experiment Stations, A. C. True, Director.
October 30, 1913.

PROGRESS REPORT OF COOPERATIVE IRRIGATION ~

EXPERIMENTS AT CALIFORNIA UNIVERSITY
FARM, DAVIS, CAL., 1909-1912. Mortars
By S. H. BECKETT, : i lel ane : ,
Irrigation Engineer. f Y os e | /
f oY De © # f
INTRODUCTION. fi) at aces {

The experiments herein described were planned and carried out for
the purpose of determining the water requirements of Various stand-
ard crops. For the purpose a tract of 25 acres on the University farm
at Davis was set aside by the college of agriculture. The work was
planned and carried on by the irrigation investigations of the Office
of Experiment Stations, in cooperation with the department of en-
gineering of the State of California, the California Experiment Sta-
tion furnishing seed and a part of the labor in return for the crops.

The University farm, comprising 779 acres, les one-half mile west
of the town of Davis. The soil, which is typical of that of a great
portion of the Sacramento Valley, is classed as Yolo loam, described
by the Bureau of Soils of this department, as follows:

The surface soil of the Yolo loam consists of a dark-brown loam of light to
rather heavy texture. The soil is usually free from gravel. Below a depth of
24 inches the subsoil is generally made up of strata of silty loam or sandy loam.
At greater depths this rests on clay loam or clay..* * #*

Owing to the excellent drainage and comparatively open texture of this type
it has proved to be well adapted to fruit, including peaches, almonds, prunes,
and grapes. * * * While irrigation has not been in general use, it has
been found to be beneficial to the tree and fruit where the lower strata of the
soil lack the close texture and compactness necessary for the retention of mois-
ture. It is one of the best general-purpose soils in the region and is adapted to
a wide range of crops.*

The mean annual rainfall, although slightly below the average for
the Sacramento Valley as a whole, amounts to 16.54 inches, the
greater part of which comes in December, January, February, and
March, while from May to October very little rain falls. A mean
temperature of 77.9° F. is recorded for the month of July, the mean

+U. 8S. Dept. Agr., Bur. Soils, Field Operations, 1909, Eleventh Report, pp. 1657, 1658.
6137°—Bull. 10—13 1

2 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.

minimum of 47.6° F. occurring in January. The maximum tempera-
ture recorded is 112° F., and 16° F. has been registered as a minimum.
These extremes are exceptional, however.

As a preliminary step in starting the experiments at Davis, a 12-
inch well was sunk near the northeast corner of the tract and a 4-inch
horizontal centrifugal pump, directly connected with a 74-horsepower
motor was installed, thus insuring a reliable water supply. Water
was delivered to the various checks and field laterals through 8-inch
galvanized-iron slip-joint pipe. When properly fitted together this
was practically watertight, eliminating loss in transportation.

Before starting each irrigation the discharge. from the pump was
measured over an 18-inch Cippoletti weir, and the measurements were
used in computing the amount of water applied.

IRRIGATION OF ALFALFA.

Operations were started in 1907, and in the fall of that year the
major portion of the tract was leveled for alfalfa irrigation. Border,
rectangular, and contour systems of checks were used, and at the
time it was intended to rely upon the open-ditch system of the
Yolo County Consolidated Water Co. for water. The accompanying
sketch (fig. 1) shows the system of checks and ditches installed, the
acreage of each check, ane its number, which will be used in future
designation.

During the whole of 1908 the land stood idle. Early in March,

1909, piete 1 to 28, 32, 33, 34, and the west half of 35, 36, and 37 were
thoroughly disked, cross-disked, harrowed, and seeded to alfalfa, 2
pounds of Utah seed per acre being used. <A grain drill, with alfalfa
attachments, was used which placed the seed at a depth of about 1 to
14 inches in the soil, in rows 6 inches apart. A good uniform stand
was obtained, and by the middle of May a 3-inch to 4-inch growth
had been made.

The following schedule for the season’s irrigation was outlined and

closely followed:
Schedule of irrigation, 1909.

‘ Bi eon Depth of

Number of plat. Number of irrigations. Dates of irrigation. water
applied.

oe Inches
LO nA pees ter VAR Saye ere aS S fs vet Novirrigation:: 2). 2926 1.. obs lesskncteccte ee ee eee
EMU] ORS ene Reo instante Ysa nize tiae a palGEN dhe oeponaabobs Haeteaoae JUNOS: 2S es Seen eee oes 15.0
SOMO este ee eee Anne see SEs Eh te Tey JeMIdSeaSO Neeser peo eee July did ee ee: ees 6.1
AQHEOML Dee ce nee he Te potce CL See UNATOSR ees ease hi eee ee August 10) seen eee 14.3
BY eRe yrs cee ed RT pete SM a ee Be Se TRAY) xp RENE een RR IE September eae eee 10.6
iN) (ay OBR Ried ate nape. 2 yee an Wearlyselilatetes- se -2 ees Wcrerenai Bos pRadseoosooa hs or ee
July 14.0 Sh ee ee 7.8
24 0 28.....-.--2--- 2222-2 eee eee 2 late....-.- 22-2. 2-22.22 ee {Angst 93) hee Sein 7.0
a sean St AUSUSUT? 3. ee eee 9.4
eee 2 very late.............-...- \eattceabee (One Pe oR oo 8.9
earlyi ec eee he Sa clone May 295 52 Nine ae einen eee 295
NGUCO RIO Veep rset mele aeerer ye ae Racy 34 MIASEASONL.o 0.4 see sea ce) DULY 1osee ee ee eee Weg,
Tate Saas ies ae ee ea ae August 23.7 oe eee | 7.0

: IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 3

During the growing season the growth and condition of the crops
were carefully observed, and at the end of the season the results were
as stated below:

No irrigation.—At the end of November only about one-third of
the stand seemed to be alive, and this had made not more than a
1 or 2 inch growth after it was first cut in June.

RMX KA KKK CRE

»
x eK
x

x x Pereran
Ki OK KM oe Xp my x
y. 2Vines,Winter Irrigated % 3
le yamine iraticiy tae I ae Pe

4 :Vines,Summer Irrigated* <
Ua ic lt i eet
Pet
a

x ux KH

Ro DOCOGOGLLOWVOGHO
x x

HO 0999990020000 0800
fot BDL HOIDOYVHOOGO
fo e@ Permanent Orcharde o
HO 99 ©0290 HA0808H9
09009000000000805
RC Eee PET Sa PORT ER pe Ey FS
* *Vines, No Irrigation * * *

a a Kx Po a a ee a aes
CVVVZTHBOSa BNC GHR0N
70 COOGDDO00O00 GO0CDO
fo CExperimental Orchard. oo}
9 SO00000000 SHH 69)
DH CVOTSBOEVEL VEOHD
79 99GOCOSQO9CGR8SOBD

cement Ppe Lines.

Side Hilf
Irrigation

IRRIGATION TRACT
UNIVERSITY FARM
DAVIS.CAL.

Fic. 1.—Irrigation tract, University farm, Davis, Cal.

One irrigation.—The alfalfa given one early irrigation showed
practically no growth after the first cutting on May 14. Even after
the heavy irrigation of June 5 it failed to make a substantial growth,
and at the end of the season not more than one-half of it was alive.
The explanation of this is that it was given too early an irrigation.
The plats were irrigated before the roots had penetrated beyond the
surface soil, and when this had dried out, following the first irriga-
tion, the roots were stranded in a surface soil without sufficient
moisture to forward the growth.

4 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.

The midsummer irrigation of July 14 produced two very light
crops and left the plants alive but growing very slowly at the end
of the season. Before this first irrigation was applied the root
system had time to penetrate well into the subsoil and receive full
benefit from the irrigation after it was applied.

The late and very late irrigations both produced one fair crop
besides the first light crop cut in May, and at the end of the season
all of the alfalfa had shown a vigorous growth, with no apparent
effects from the early drought, indications pointing toward a good
yield in the spring.

Two irrigations.—In the plats given one early and one late irriga-
tion only a 2-inch growth was shown between the cutting in the
middle of June and the irrigation on August 10. Following the first
irrigation the alfalfa made a slight growth, but it was not until after
the second application that a substantial growth was made, which
produced one fair cutting in September.

One midsummer and one late irrigation produced a fair cutting
in September, followed by a second and much heavier crop early in
November. At the time of this last cutting the stand was in very
good condition, the plants being deep-rooted and sturdy.

Two late irrigations of 9.4 and -8.9 inches, respectively, applied
August 1 and September 9, produced two good crops, the first on
September 7 and the last November 12, and at the end of the season
these plats had not only produced the heaviest first-season yields,
but contained the hardiest and best appearing plants.

Three irrigations—In these plats the first and heaviest irrigation,
applied May 29, seemed to have little effect upon the stand aside
from keeping it alive; but after the second apphecation, on July 13,
the growth was rapid; and following the third application of August
23 a heavy first-year crop was taken off October 12, and a second fair
crop in November, and at the end of the season the plants seemed to
be very well developed, indicating probable heavy yields the following
spring.

Late in November plats 35, 36, and 37 were all given a very heavy
early-winter irrigation. This was waste water pumped onto the
plats during the testing out of the pumping plant, and, all told, the
water applied must have amounted to a depth of about 18 inches.
This seemed to have a remarkable effect upon the stand and was
directly responsible for a heavy yield with small amounts of water
the following summer.

Although no definite conclusions can be drawn from a single
season’s observations, nevertheless the results obtained point to the
following facts:

(1) Without irrigation spring-sown alfalfa is uncertain in Sacra-
mento Valley, and under conditions of normal rainfall and moderate

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 5

climate not more than one-half of the stand can be expected to sur-
vive through the summer.

(2) Heavy spring irrigations, when followed by long periods
throughout the summer without water, did not benefit alfalfa. Exam-
ination of the root growth under these conditions shows that water
applied to the little plants in the early spring produces a root growth
outwardly along the surface of the soil rather than downward, and
when this is followed by long dry periods, the soil drying out leaves
the young plant stranded above the moisture zone. Far better results
were obtained by delaying irrigation until the root growth was well
established, and even until the little plants seemed to be stunted and
suffering for moisture. Well-developed, deep-rooted plants mean
heavier yields.

(3) Late and very late summer irrigations tend to produce sturdier
plants and heavier yields the following summer.

(4) After the root growth is well established, the growth may then
be forced by frequent and, if the soil will stand it, heavy irrigations.

; DUTY OF WATER FOR ALFALFA, 1910, 1911, AND 1912.

The investigations during the first year’s growth of the alfalfa had
naturally destroyed the uniformity of the stand, making it necessary
to reseed the whole area. Early in March the ground was thoroughly
disked, cross-disked, and harrowed to a depth of 2 inches. It was
then reseeded, 20 pounds. of Utah seed per acre being drilled in at
right angles to the seeding of the year before. This seed was brought’
up by the early spring rains and at the time of the first cutting on
April 21 a very uniform stand covered the whole area.

The previous year’s work had shown that the water supply from
the ditch system was inadequate for experimental work, and the
pumping plant was installed and used in all subsequent work, the
ditch system being abandoned.

The following schedule for irrigation was outlined and followed on
all but three of the checks in 1910 and 1911:

Schedule of irrigation of alfalfa, 1910 and 1911.

Depth of
Number of plat. Area. water Schedule.
applied.
Acres. Inches.

ViPS Bia Gls nouns are OSPR Goddeoneus No irrigation.

Qa OS ola eee sie ie te te he SOBOillbooSandoos Dor

CT re ee A . 293 12 | 6 inches after first and second cuttings.

Ths NG} See ARS coh UR . 652 24 | 8 after first, second, and third cuttings.

DOE DAS Dy rar ae vei . 960 30 | 72 after first, second, third, and fourth cuttings.

TCAs IAS PS Sea Se eee . 920 30 | 33 Inches one week after first, second, third, and fourth cut-
tings; 3% inches before second, third, fourth, and fifth
cuttings.

PAD, DA OX OA es NaN i NE - 920 30 | 74 ene one week before second, third, fourth, and fifth
cuttings.

BBS ois ees eye ATRIA oe 1. 000 36 | 12 inches after first; 8 inches after second, third, and fourth
cuttings.

CV at ea ae ea . 573 36 | 9 inches after first, second, third, and fourth cuttings.

OO ferapare cere eyere ns Mal) ta 1. 000 48 | 12 inches after first, second, third, and fourth cuttings.

Gre Soe Scere . 513 48 Do.

6 BULLETIN 10, U. 8. DEPARTMENT OF AGRICULTURE.

A winter irrigation applied to checks 35, 36, and 37 produced a
marked improvement in the stand which was carried over into the
following season, producing much heavier yields. For this reason
they were treated separately, the following schedule being used:

Schedule of irrigation of alfalfa, 1910 and 1911.

This work was continued during the season of 1912 but on a re-
duced area, rectangular checks 17 to 31 being devoted to the work.
Application of equal amounts of water to these checks during 1910
and 1911 had produced a very uniform stand over the whole area, and
the experiments were started in 1912 under very favorable conditions.
Following is the schedule outlined and followed during the season:

Schedule of irrigation of alfalfa, 1912.

Depth of |
ND Area. water Schedule.
QUORI Te applied.
Acres Inches
7, 30 DPAG nee we eee No irrigation.
te 29 . 46 12 | 6 inches after first and second cuttings.
19. 28 - 46 18 | 6 inches after first, second, and third cuttings.
20-27 - 46 4 6 inches after first, second, third, and fourth cuttings.
21-26 . 46 30 | 74 inches after first, second, third, and fourth cuttings.
22-25 - 46 36 | 9 inches after first, second, ‘third, ‘and fourth cuttings.
23-24 - 50 48 | 12 inches after first, second, third, and fourth cuttings.
31 39333. 60 | 12 inches after first, second, third, fourth, and fifth cuttings.

During each of the three seasons six crops of hay were cut. In
harvesting, the general practice of cutting when about one-third of
the alfalfa is in bloom was followed. The hay was generally raked
the same day, shocked the day following, and hauled as soon as it
was dry enough to be stacked without heating, never waiting until
the leaves were dry enough to fali off when handled. The results
of these experiments are given in the table following.

——

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. a

Summary of results of alfalfa irrigation investigations, 1910, 1911, and 1912.

; Yield in tons per | Value of hay per “pace se NT ;
ee acne acre at $7 per ton. Cost of production. | Net profit per acre.
Depth of water
applied. aan RL Ca |
1910 | 1911 1912 | 1910 | 1911 1912 1910 | 1911 1912 1910 191i 1912
Inches. | |
(Osis ae tN a ee 3.85 | 6.02 | 6.52 [$26.95 |$42.14 |$38. 64 | $8.65 [$13.50 |$12. 40 |$18. 30 |$28. 64 | $26. 24
| ee ea and meee eee 4.75 | 7.52 | 6.51 | 33.25 | 52.64 | 45.57 | 13.40 | 19.60 | 17.35 | 19.85 | 33.04 | 28.22
TSS os2 2 Se chin Sree Speen Sa oeee ToW2 |-osassalleesoosc ee Ol eese cies eee eee HORS a |e eae Hee es 2 29. 29
DAE pees SE | 6.00 | 8.38 | 8.32 | 42.00 | 58.66 | 58.24 | 18.90 | 24.20 | 24.10 | 23.10 | 34.46] 34.14
MU csecasecocecadcall (eos) VEO) Cee R Gye ral Gye Pl les Gul |) Pas 15 I) 27/6 ths |) PG Bis |) AERO Se al) BES}
SO ee aa eee asin | 7.58 | 9.33 | 9.38 | 53.00 | 65.31 | 65.66 | 24.15 | 28.05 | 28.10 | 28.91 | 37.26 | 37.56
pene Oe aS aa 8.45 | $. 64 | 8.87 | 59.15 | 67.48 | 62.09 | 27.80 | 30.25 | 28.80 | 31.35 | 37.23 33. 29

EV ca ae ee Nip ea rood: |(oametes [naa F500 Sees ees 5), (15h na aa te ~.| 36.63

Norr.—Labor of production figured at $2.25 per ton. Water figured at $1.70 per acre-
foot. Labor for irrigation figured at 50 cents per acre per irrigation. While the value
of the hay is figured at $7 per ton for each of the three years 1910, 1911, and 1912, the
local value in 1912 was $11 per ton.

The accompanying diagram (fig. 2) shows the average yields in
tons per acre for the three years, with the corresponding depths of
water applied, and figure 3 shows the average yield in tons per acre
for each cutting from the unirrigated alfalfa and from the checks

given 30 inches in four 74-inch ap-
4 f TH OF WATER IN INCHES
plications. |-o [12 | 1s | 24] 30 | 36 | 48 |

The first diagram shows a very
uniform increase in yield up to 30
inches of water apphed, above
which the increase is very small,
and in the case of 36 inches ap-
plied a shght decrease is shown,
although the maximum average
yield was produced by a total of
48 inches apphed in four 12-inch
irrigations.

The first half of the diagram
shown in figure 3 illustrates the
gradual decrease in yield in each
succeeding crop where no water is
applied, showing the need of irri-
gation after the first crop has been IIc. ee yield of AS 1910,
removed. When this first half is 1911, and 1912, using different quan-
compared with the other half of piles geen ters
the diagram the result of irrigation is apparent. In each of the
three seasons the maximum yield was produced in the third crop,
probably because of more favorable growing conditions during June
and the first part of July in which this crop was grown.

YIELD IN TONS PER ACRE

8 BULLETIN 10, U. §. DEPARTMENT OF AGRICULTURE.

The results, although not absolutely conclusive, point to the fol-
lowing facts:

(1) In the open, well-drained soil, typical of that found in the
floor of the Sacramento Valiey, the general tendency is toward an
increase in yield of alfalfa with the increased amounts of water ap-
plied up to at least 48 inches.

(2) There is a limit beyond which the increase in yield will not
pay for increased cost of applying the water, and for such conditions
as are found on the University farm this limit is in the neighborhood
of 30 inches applied as a total for the season.

ieee UNIRRIGATED | FouR 7/2 1N.IRRIGATIONS

CROP CROP

| |
| ist |2np|3R0/47H| StHoTH| Ist |2nv|3 Ro 47H |StH/6oTH!
aval ead 2S eee mais

staal
Cees etisiows co
i MEG Goa He ie
i Me Be ie Coon
MMT Me Le eco
i ee
EME 2 oe ro oe
i em ee

| Oe Ge oC
Be On Ce I es
Fig BE ee HEB BS eS Geo,
SEER a ena
CA Pe ae a
BS 6 Be oe ee eo ee
GSE BS ee Meee Be ee eee oe
8 Ge Ge Oe Bee be Se Gece Loe
<8 OG Se 28 60 Oo ee Oe Ee oe
[OC eee

Aa GS OG ee Be

Fic. 3.—Comparative yield of unirrigated and irrigated alfalfa, by crops

In applying these conclusions to other localities, it is well to re-
member that local conditions are always the controlling factors.
The character and condition of the soil, the climate, the rainfall, the
length of the growing season, and the age of the alfalfa, all have
their effect upon the yield, and each general locality will show differ-
ent results and a different economic duty of water.

WHEN TO IRRIGATE ALFALFA.

In order to determine if possible at what stage of growth after
cutting the water should be applied to produce the best results, checks
17 to 28, inclusive, were divided into three groups of four checks
each, and during 1910 and 1911 they were treated in the following
manner :

ace rh a

5 See | F our 7}-inch irrigations applied just before cutting.................- 7.97 |

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 9

Group 1 (checks 22, 23, 24, and 25) received a total of 30 inches,
applied in four Bee irrigations, immediately following the first
second, third, and fourth cuttings.

Group 2 (checks 20, 21, 26, and 27) received a total of 30 inches in
eight 32-inch irrigations, two irrigations being applied between cut-
tings, the first one week after cutting and the Sane two weeks later.

Group 3 (checks 18, 19, 28, and 29) received a total of 30 inches in
four irrigations of 74 inches each, applied just after cutting the sec-
ond, third, fourth, and fifth crops.

The results obtained are shown in the following table:

Results from irrigating alfalfa at different stages of growth.

| | Total yield for season in
toms per acre.

Number | Schedule.
of group | ‘
Q AVer-
| 1910 | 1911 | “o5e
| |
je ee | Four 73-inch irrigations applied immediately after cutting..--....... 7.53 9. 61 8. 57
DO) ge a Se | Eight32-inch irrigations applied in two irrigations between cuttings. §.24 | 9.91 9.08
&. 95 | 8. 46

Each of these seasons shows a small increase in yield to be pro-
duced by two irrigations between cuttings. This averages 0.5 ton
per acre for the two seasons, and if the extra labor, such as laying
the pipe and preparing for the irrigation. is considered, the small
additional profit is consumed in labor, and from a financial stand-
point no advantage is gained.

In heavy soils, s subject to cracking after irrigation, frequent ap-
plication of small amounts of water roe a decided advantage over
the single irrigation between cuttings. It is true also, in light porous
soils where the underground drainage is good and the moisture-
holding capacity of the soil is small, that one heavy irrigation will
not carry the crop through to a good yield and that a second ap-
plication will produce good returns.

The groups 3 and 1, irrigated before and after cutting, show op-
posite results for the two seasons, irrigation before cutting showing
the heaviest yield in 1910 and the lightest yield in 1911, but in each
case the difference is so small that no conclusions can be drawn favor-
ing either method. It was noticed, however, that toward the end
of the season of 1911 the checks irrigated just before cutting had a
very spotted appearance, the alfalfa standing at a very uneven height.
and that after cutting, in spots the alfalfa was slow to start its new
growth. A period of five days to a week always elapsed from the
time of irrigation until the crop was cut. During this time the
growing alfalfa was drawing heavily upon the moisture supply in

6137 °—Bull. 10-132

10 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.

the soil and in spots seemed to diminish it to such an extent that not
enough remained to produce a vigorous growth in the plants after
cutting.

IRRIGATION OF GRAIN, 1910, 1911, AND 1912.

During these three seasons the east halves of checks 35, 36, and 37,
containing one-half acre each and 14 acres of unleveled land lying
north of check 37, were given over to experiments with irrigation of
barley.

During 1909 checks 35, 36, and 37 were planted to sugar beets,
which were irrigated. but the amounts of water added were small,
and it is safe to assume had no effect upon the crops which followed
in 1910. The unleveled area north of check 37 had been cropped to
grain for a number of years previous to beginning the experiments,
and was typical of much of the so-called “ worn-out ” land in the
vicinity of the farm.

Season of 1919——During the season of 1910 all plats were plowed
in the early spring, harrowed, and drilled to barley on March 12, 85
pounds of seed per acre being used. The following irrigation sched-
ule was planned and carried out.

Schedule of irrigation of barley, 1910.

= = Mats = 26 Se a Depth
Number oi plai. Number of irrigations. Dates. applied
Inches
Unleveled area..... Nodmisation=: 2 <=9-6 ae eee eS. ee ee
Soe Bee eee ae One irrigation (flooded) - .-....-...--------- oe Ae eh wie ee 27 3.6
p PioAaniani halle £ =) | esi yee 3 3.6
ST Rae eee Two SRS UIs shallow furrows)- 2--2- 2 2) eee eee \May 17 26
SY fe te ae i ‘wo irications (deep furrows) 926 25 ee ee ee Sse Re eee

Plats 56 and 37 were furrowed immediately after seeding. The
shallow furrows of plat 36 were made by a marker consisting of two
6 by 6 inch timbers, 24 feet long, set on edge, 18 inches apart, and
fastened parallel to each other by 2 by 4 inch cross strips. This was
drawn over the surface parallel with the checks, making shallow
furrows 18 inches apart and averaging 13 inches deep. This method
is practically the same as fiooding, the furrows acting simply as
guides for the water.

It was intended to irrigate plat 37 by subirrigation from deep
furrows. but the method was not successful, and May 1 the check
was plowed and seeded to cowpeas, which were turned under as green
manure in the fall.

The dates of irrigating plats 35 and 36 depended entirely upon the
condition of the crop. the water being added when it was thought it
would produce the best results and in quantities sufficient to give the
soil a good irrigation.

eS SSS Se CCU Ch

~ i ee

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 1t

Season of 1911.—The experiment was repeated in 1911 on the same
soil, following as nearly as possible the procedure of 1910, the land
being spring plowed and seeded on March 20.

The following schedule was followed during the season:

Schedule of irrigation, 1911.

Number of Depth
Number of plat. irrigations.| P@'- | applied.

Inches
Wnleveledsarca=—mort lawl alley ts eee eles sien ety eee INO Men eee nee ee ca meee)
Wnlevelediarea—soubhwlbalty se ee es fe eee Onewess: June 1 6. 4
BN GOSHS CORO ACES AE SESS CLUS ERE Cts em ose oa ni ey aa Mrs ua I SEO) ae May 13 4.3
BH as 5 SSA atc NE OI ea REE ar Ga RO Daas ees Rana ee ae RE TN Reeser O10) Soc ser loaeOl@,o% 6.0
ifteedowe 4.3
SO a i le a Two...... {itay 27 2.7

1 Green manured.

Following the seeding the weather remained cold, and at the time
of the first irrigation, on May 13, 54 days after seeding, the grain
stood at an average height of only 6 inches. The second irrigation
was applied to plat 35 just as it was coming into the head.

On June 1 the unleveled area was divided into two plats, and the
south plat flooded to a depth of 6.4 inches. At this time the grain had
just come into the head and was beginning to show indications of a
lack of moisture. In irrigating the remaining plats (35, 36, and 37)
the water was applied at a time when it was thought it would pro-
duce the best results. |

Season of 1912.—Following the harvesting of the grain in 1911,
checks 35, 36, and 37 were irrigated and plowed, and on July 22
planted to cowpeas of the Clay variety. Early in November these
were turned under as green manure.

February 3, 1912, these checks, as well as the unleveled area to the
north, were plowed, harrowed, and seeded, using the same variety of
seed, quantity, and method of seeding as in the previous two years.

Schedule of irrigation, 1912.

Number of plat. Number of irrigations: Date. _| eo eas

| Inches.
Unleveled area..... INTC eased ralcerriee HC ea OA Need TalgON OR LIAN SPP Kee ee IPL Me eee ae LT. idee Ea
Bal ee AE Fe oe eee | eee GO) FOES S a Ns SAIS GES PERE GO REIEG eR eta UAE <a Rta tel Sn Sie el ea ee
SiO ee SaaS ae ee OI 5 6 Biase bo eesOE don 5 ABER SAI ee Se BS GO Oe aS e tereteeaiias Apr 24 7.35
| {Apr 17 12.00
Tee TWO... -..----- +++ 22+ - 20222 ee eee ee ee eee eee eee cess \May 8 5.95

1 Green manured.

Tt will be noticed that much heavier irrigations were applied here
than in the other two seasons. In all cases sufficient water was added
to give the soil a thorough wetting. The green manure seemed to pro-
duce a loose, porous soil which rapidly took up the water as it was
applied. This condition will be noticed also in plat 37 of 1911, when
6.03 inches were added, as against 4.3 inches to the unmanured checks.

12 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.

The following table shows the results obtained from the three
seasons’ work, and these are further illustrated in the diagram (fig.
4) in which the yields of grain in pounds per acre are platted. with
the corresponding amounts of water applied.

Yield per acre.

Rainiall ~ “ee Cost of
Season. for Number of plat. N pres HEE | Depth.|—_——___——_—_ Value. irriga-
season. Hay. aan tion
Inches. Inches.| Pounds. | Pounds.
Unileveled area.= .| None....---2.-|.--- 2 3,120 4, 1607) S17: 40°} te
age es 11 OD abies te ee Que ee 3.6 3,440 1,480 | 22.20| $1.08
Gee eee WO see ea ee 4,460 1,84 7.30 1.56
‘Unieveled area || None 3 oe (b ea 1,560 905 1: 12°08) | eee
(north half).
Sb. Bee ree ee One early ....- 4.3 2,040 1,108 | 16.62 1.29
cy be ane oe 33.18 |{ Unleveled area, | One laie......- 6.4 2,720 1,520 | 22.80 1.92
| (south half).
35 Sat Ae eee TWO) oe 7.0 3,180 1,819 27.15 | 2.10
Sy (ees Se eee One early - ---- 6.0 3,740 2,146 | 32.19 | 1.80
Unileveled area_-...| None.....-..22).2.-.- <2 680 345 mA S3) = ees
F 2 OD ee ae ee ee | eee CO S222 as eee 1,925 1,00 15603225.
1912...----- of AO NGG Te a pee One) ie toed 7.35 2, 420 1,280 | 19.20 2.20
ced eee ne ee ee TWOs = Ses eee 17.95 3, 780 1,950 29.25 5. 38

1 Green manured.
Note.—Irrigation cost figured at 30 cents per acre-inch for marking furrows, power, and attendance.
Grain yalues figured at $1.50 per hundred. Value of hay is disregarded.

Weather records taken over the entire period of the experiment
show that these three years represented extremes in rainfall and gen-
eral weather conditions. Never-
theless, under all of these vary-
ing conditions there is not one
instance where the increase in
yield did not more than pay for
the cost of the water which pro-
duced it, the yield increasing
with the increased amounts of
water applied.

It will be noted that in each
of these seasons two irrigations,
one of which was applied at
about the time the grain came
to a head or soon after, or one
late irrigation, as in 1911, pro-
duced a heavy yield above the
single early irrigation. In each
of these three years strong, dry-

ing north winds occurred about
Fic. 4.—Yield of barley with different quan- . . :

tities of water, on manured and unmanured the time the grain was I the

lard. dough. The unirrigated and
early irrigated grain was badly pinched, while the presence of the
moisture in the checks irrigated late seemed to prevent this, pro-
ducing full, plump grain.

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IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 13

- Were further conclusions to be drawn each season should be con-
sidered separately, but in each case inspection of the value column
will show that for each of these three seasons irrigation of grain was
made to pay.

IRRIGATION EXPERIMENTS WITH INDIAN AND EGYPTIAN CORN IN
1910 AND 1911.

For this work, which extended through 1910 and 1911, the 4-acre
tract lying directly north of the west end of check 87 was used.
During 1909 this tract was in sugar beets, and previous to that for a
number of years it had been in grain.

In the spring of 1910 it was plowed twice—March 1 and April 9—
harrowed, and cross-harrowed. On April 29 the west 2 acres were
seeded to Yellow Dent Indian corn and the east half to Egyptian
corn (white durra), a sorghum. In seeding a corn’ planter was used
and the rows were placed 40 inches apart.

During*the season of 1910 no definite time for irrigation was set
or definite quantities assigned, both being controlled by the needs and
conditions of the growing crops.

INDIAN CORN.

Immediately after planting the field was divided into four plats,
the water being applied as shown in the following schedule:

Schedule of irrigation of Indian corn, 1910.

Number of plat. Number of irrigations. | Date. aoe ted,
|
|
| Inches
ies Seb S kSS SoS ee eee INIOVIVE aig He oper Pe es iret ge ae AM ee os Coe eae [pees ene otal Pay score tt ate
Ds Eb5ee = 8 Saas hoe Een eaae O)TIC Se ee Sra tr ever hoe: nay i ee Oe 24 3533
Wise sesce 3.3
ee TWO... .------- 22-22-2222 22 eee eee eee eee iuly 13 2.0
|(May 26 4.4
Ae eee Soe aE age ene disse eee ease BDRCC wc e as ment eascieheiice seem sneer ewan joane 24 Qed.
\(\July 13 1.5

Thorough cultivation followed each of these irrigations, and at all
times the field was kept free from weeds. In the middle of August,
when the corn was in the milk, it was cut, weighed, and fed green.

After the crop was removed the land was fall plowed, harrowed,
and allowed to stand idle through the winter. The following March
it was again plowed, harrowed, and seeded to * Yellow Flint ” corn
and the experiment of 1910 repeated. The area was divided into
four plats, which received the following amounts of water during
the growing season.

14 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.

Schedule of irrigation of Indian corn, 1911.

~ Depth of
Number of plat. ee of Date. water Status of corn.
gations. applied.
a
Inches
1 ee Sie ae ie INOMe@ = DRE Cs |E Lest pane Cl oan omer eee :
OE RSE Geet ame ee eee One aaaes June 22 2.3 | Corn 20 inches high:
3 Two Nui 21 2. 2 KOC age
picnic iaur ween ata || aoe a. Mehr re July =— 17 2.5 | Corn coming in tassel.
jJune 21 2.3 | Corn 20 inches high.
Aa incnie ane 2k imhreeseess July 17 2.4 | Corn coming in tassel.
Aug. 8 2.4 | Corn coming into the milk.

In each of these irrigations the furrow method was used, a small
stream running in each furrow for a long period, thus avoiding
flooding and, as in previous seasons, a thorough cultivation following
each irrigation.

August 16 and 17 the corn was harvested, weighed, chopped, and
stored for winter use. | 2 3

The following table shows the results obtained for the two seasons:

Summary of results of irrigation of corn.

Value at | Cost of

Season. ee Number of irrigations. | Depth. ee er! $2.50 irriga-
Bot | * | per ton. | tion.
}
| Inches Tons.
AD WeNOM G22 hk eet UR ee a oe a ed Sea eee | PRR 6.85 Cel) Week Seok.
1910 | Di SOMOS Fea eee oe a 3.3 8. 85 22003 $1. 50
Seis nici se tie Gite =o Se SDS O tn Gere A Oe oe ae eee | a3 10. 05 74ay J 2.60
| AUN reas ce: Ee a | 8.0 10. 45 26. 13 3.90
SAN MC Soh sn Sop ese ee ote een Nee epee ea Fa 3. 67 ON183 Gea
1911 YAP OW oY baheatenet et sates ted a CE CRE See 3.0 4. 86 L205 1. 40
wert eeese reese SAT wor ere. hae ke ern 4.8 5.21 13. 03 2. 45
| PW Ha Be 0 a2) = alee Renee ss etre Sea coe A | eal 6. 59 16. 48 3.65

Note.—Cost of irrigation taken at 30 cents per acre-inch for water and application, plus 50 cents per acre
per irrigation for furrowing.

The most noticeable feature in these results is the decrease in yield
in 1911, when compared with the yield in 1910. This is due entirely
to the character of the season. The late spring of 1911 was abnor-
mally cold and very unfavorable to the production of a good yield,
even in the presence of an abundance of moisture.

During 1910 one and two irrigations were applied to advantage,
while ihe third irrigation just before harvesting produced an increase
of but 0.4 ton per acre green weight, and was spplied at a loss.

The season of 1911 shows light yields and small increases, and if
interest on the investment in pumping machinery and cost of leveling
the land be added to the cost of irrigation no financial gain would be

realized.
EGYPTIAN CORN.

This investigation followed along the same lines as the investiga-
tions with Indian corn, the preparation of the land, time of seeding,
and entire procedure being the same up until the time of the first

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 15

irrigation. It was noticed, however, that the Egyptian corn (white
durra) was much slower in coming up, and in the early stages of
growth developed very slowly, especially during the cold spring
weather of 1911.

The area originally was divided into three plats, No. 1 containing
0.9 acre; No. 2, 0.46 acre; and No. 3, 0.67 acre. About the middle of
June it was seen that the yield from the unirrigated plat, No. 1, was
going to be small, and it was then subdivided into plats 1-A, 1-B,
and 1-C, of 0.3 acre each. Plat 1-A was not irrigated, plat 1-B re-
ceived one irrigation, and plat 1-C two irrigations. Following are
the dates of irrigation and the quantities of water applied:

Schedule of irrigation of Egyptian corn, 1910.

1-C...-. 2.222222 ee | TWo..-..-..-.---- {iuiy 14 1.75 | Corn forming heads.
DRM es. 882 Ones eat | July 13 3.10 | Do.
3 Tie ae 28 3.25 | Corn 4 inches high.

THRE LS he ee ae Re ee July 14 2.10 | Corn forming heads.

During 1911 the experiment was repeated on the same soil. The
first seeding on April 18 was a failure, and only about one-fourth of
a stand came up. The plat was replowed, harrowed, and reseeded
May 13 and a good stand obtained. The area was then divided into
four equal checks and the following irrigation schedule outlined :

Schedule of irrigation of Egyptian corn, 1911.

In all irrigations the furrow method was practiced, the water being
applied in alternate furrow spaces. A thorough cultivation followed
each irrigation, and the whole area was kept free from weeds during
both seasons.

In harvesting, which occurred the first of October, the heads were
picked, hauled, and thrashed, and later the stalks were cut with a
mowing machine.

16 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.

The following table shows the results of the two seasons’ work:

Summary of results of irrigation of Egyptian corn.

Z se Value at Cost of
Season ESIaE ‘ Number of irrigations. Depth. ¥ st $1.50 per | irriga-
: ; 100 pounds.) tion.
Inches. Pounds.

I-A None-22. 2. 2 ee eee 1,335 $20: 03 >| -2o2e ei
cB spain OnelAk. Bice = 2S eeu aye fa) 2,670 40.05 $1.52
AOIQis. es Ae IGE TWO SPS ee ee ee eee 5. 50 27 40. 50 2.65
2 See Onan a. ne ee 3.10 2° 510 37. 65 143
[BEaae ae WO? Les ce Se ee ee 5.35 3,340 50. 10 2.60
(3 Mee INOHE: < Seo ee eee eee Eee eee 1,100 16:50; 5250
a KIYIs [) ote e Bice 2 egg Ec. ae Orie te ok a eee Been 1.8 1,690 25.35 1. 04
E E Stee SUS oe WG See. eee eee eee ae ete 4.6 2, 650 39.75 2.38
“ee RATES. oe ae Pees ee eee a5 T/ 2,964 44.48 3.20

Note.—Cost of irrigation is taken as 30 cents per acre-inch for power and attendance, plus 50 cents peracre
per irrigation for furrowing.

The accompanying diagram (fig. 5) shows the results for 1911,
platted graphically, the yields with the corresponding amounts of
water apphed being shown.

With this crop, as with the Indian corn, a greater yield is pro-
duced in 1910, with less amounts of water applied, than in 1911, due
entirely to a warmer spring and much
more favorable growing season.

The results for 1910 show but a small
variation in the yields from plats 1-B,
1-C, and 2, and a large increase in plat
3. This is due to the time of irriga-
tion, plat 3 receiving one early and one
midseason irrigation, the first apphed
before any effects of drought were
shown, thus keeping more or less of a
constant moisture percentage in the
soil during the entire period of growth.
In 1911 the yields increased quite uni-
formly with the increased amounts of
water appled, until the third irriga-
tion, when there was a slight falling off. When this last irrigation
was applied the heads were fully formed and the grain ripening,
and the only effect of this irrigation was probably in preventing any
pinching or shrinking in the grain.

Inspection of the value column for each season shows that the
irrigation of this crop may be made to pay, even if 6 per cent interest
on an investment of $50 per acre for leveling the land and developing
water be added to the cost of irrigation.

Here, as in the irrigation of other grain crops, no definite duty of
water can be established. The amounts of water required and the
time of irrigation will always vary with the season, and the intelli-

WATER APPLIED-INCHES

| o | 18 | 46] 57 |

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Fie. 5.—Yield of Egyptian corn
with different quantities of water.

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. Ave

gence of the irrigator along these lines is always going to be the con-
trolling factor in success and failure or profit and loss. That the
time of applying water is of as great importance as the quantity of
water applied is shown plainly in 1910, in plat 1-C, where two irri-
gations followed in close succession and the increase in yield due to
the second irrigation did not pay for the cost of the irrigation.

IRRIGATION AND CROP ROTATION EXPERIMENTS IN 1912.

It was decided in the fall of 1911 to turn under a part of the
alfalfa as green manure, and in the spring of 1912 to start a crop rota-
tion of grain, sugar beets, corn, and potatoes, following alfalfa, these
crops to be investigated from an irrigation standpoint, showing the
increase in yield, with the increased amounts of water apphed. Com-
parison also was to be made with the returns obtained from the un-
fertilized soils in previous years.

Early in November, 1911, plats 1 to 15 and 32 to 37 were plowed to
a depth of 8 inches with a two-gang plow. At this time the alfalfa
had about a 6-inch top growth, and a good covering of green manure
was turned under. Following this plowing the land was harrowed,
cross-harrowed, and disked, leaving it in a finely pulverized condition
to receive the winter rains.

On February 1, 1912, the land was replowed to a depth of 6 inches,
harrowed, and cross-harrowed. Owing to the light winter rains the
green manure had not thoroughly rotted, although the soil turned up
in a fine, mellow condition, presenting the appearance of recently hav-
ing been given a heavy application of rotted stable manure.

Owing to the checking system of plats 1 to 15, it was necessary to
relevel them for furrow irrigation. This area was later seeded to
sugar beets, Indian corn, and Egyptian corn.

GRAIN FOLLOWING ALFALFA.

Following the replowing and harrowing on February 1, the east
halves of checks 32, 33, and 34 were seeded to 60-day oats, 75 pounds
of seed per acre being planted. At the same time the west halves
of these checks were seeded to Australian white wheat, at the
rate of 85 pounds of seed per acre. All of the seed was drilled in,
the drills running lengthwise with the checks, and a good stand came
up on all of the checks.

18 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.
The following plan of irrigation was outlined and carried out:

Schedule of irrigation of grain following alfalfa in 1912.

OATS.
Number of plat. Number ofirrigations. Date. Depth. Status of oats.
Inches.
SDE Ste om eee Se INone<<2. + tsa ee en ee ee
3 Apt eee One os nae April 9---- 13.2 | Oats 12 inches high.
fApril 13... 13.2 O.
Se aie ie a Ge May 10. .-- 7.2 | Oats heading out.
WHEAT.

Sede ns gee Saar ae INONG 2252 aoa oe eee eee
See at set oy hues One fae 2 ee April 25... 10.00 | Wheat 24 inches high.
34 Two fApril 15... 9.15 | Wheat 18 inches high.

Ie ig age ran ae Sake dest pe TIM BYio 8.40 Wheat coming into full head.

Tn each irrigation water was added at a time when it was thought
that the best results would be obtained, and in no case was irriga-

ong be

L2trrgenens | |

4
c
-S
=
-\ -
C
=

Fic. 6.—Yield of oats and wheat,
with different quantities of water.

tion delayed until the crop was suffer-
ing for moisture. It will be noticed
that in all cases large amounts of
water were used. This was necessary
in order to cover the checks completely
and was due to the open, porous con-
dition of the soil, the result of turn-
ing under the green manure.

Early in June, just before harvest-
ing, several days of heavy north wind
occurred, badly shattering both crops,
and it was estimated that 30 to 40 per
cent of the grain was lost. This loss
is not included in the table of yields.
June 15 all plats were cut with a
binder, stacked in the field, and later
thrashed with a stationary thrasher.

The table following shows the yields
in hay and grain in pounds per acre,
the quantity of water applied, and the
cost of irrigation. The accompanying

diagram (fig. 6) shows the yields of grain platted with the corre-
sponding amounts of water applied to each check.

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 19

Summary of results of oats and wheat irrigation.

‘Yield per acre. Grain
x5 Number} Numberof | pepih Fine value at ue of
P- of plat. irrigations. pt. ae $1.50 per ti a
Hay. Grain. 8 * | 100 pounds. ;
Inches. | Pounds. | Pounds. | Per cent.

Be aacoae INOTe es Re Seen eer 1,380 435 31.8 SONU ES eee cane
ater ied N33 tee ten Oneness aa 13.2 4, 900 1, 420 28. 0 21.30 $3. 96
Oy ae ene ae UNiOadus scares 20. 4 5, 820 2,040 35.1 30. 60 6. 12
By ata IN OTE we ye reroll ee se eae 1, 730 560 32.4 Sed Ores aS
Wheat....... Bonn ate One ee Ss 10.0 3,920 1,210 30.9 18.15 3.00
Cy elas ale Twos eseues eee 18.4 6, 300 1,935 30.8 29.03 5. 52

NoTE.—Irrigation cost figured at 30 cents per acre-inch for power and attendance.

With the oats the single irrigation of 13.2 inches increased the yield
225 per cent, giving a gain in returns of $14.77 per acre, at a cost
of $3.96 per acre for irrigation. Two irrigations, totaling 20.4 inches,
increased the yield 370 per cent, with a gain of $24.07 per acre in
grain value, at a total cost of $6.12 per acre for water and attendance
during irrigation.

Figuring on the same basis with the wheat, one irrigation of 10
inches increased the yield 116 per cent, with a gain in returns of $9.55
per acre, at a total increased cost of $3 per acre. Two irrigations
increased the yield 245 per cent, giving an increase in returns of
$20.63 per acre, at a total expense of $5.52 per acre.

It will also be noted that in all cases the percentage of grain to
hay remains about the same, showing the grain production to increase
uniformly with the total weight of matter produced,

No definite conclusions can be drawn from this one season’s work.
A decided advantage, nevertheless, is shown in favor of irrigation.
All of the water was applied at a financial gain, and an idea is
obtained of what may be accomplished in years of light rainfall
when conditions are unfavorable to dry-land farming.

SUGAR BEETS FOLLOWING ALFALFA.

Following the early spring preparation of checks 1 to 15, the land
was replowed on February 22, then harrowed and cross-harrowed.
The area was divided into seven plats, 5, 6, and 7 to be seeded early,
and 1, 2, 8, and 4 seeded later. March 11 the first plats were seeded
in drills 20 inches apart, 15 pounds of Wankaka seed per acre being
used. March 27 the remaining checks were seeded in the same
manner. Spacing, thinning, and hoeing followed when the beets were
in the third and fourth leaf, and this was followed by .a thorough
cultivation.

The dates of irrigation depended upon the needs of the crop, and
sufficient water was added to give the soil a thorough wetting. The
furrow method of irrigation was practiced, the water being applied
in alternate spaces between the rows, and as nearly as possible the
water was confined to the furrows and kept away from the beets.

20 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE.

As long as the size of the beets permitted, thorough cultivation fol-
lowed each irrigation, and all plats were kept free from weeds.

Following are the dates of irrigation and the amounts of water
apphed:

Schedule of irrigation of sugar beets in 1912.

: ¥y é Number - Se es ae Depth
Time of seeding. of plat. Number of irrigations. | Daie. snpled:
| | ra a a =
: . Inches.
5 (3 ONG: s2. 2h. kes F. See See Ae Be ts
Marly Mar, adie 2 22-2 ees et Dy MBSE 5s Seek [4252 e hs Soe 555s May 21 10.5
| - lh és May 21 9.2
Lae Ran aos apaarpe eee June 21 4.4
1 ENO eee Se ee elo cio ee
2 On xc eint Me Soe i ee SE ee | May 24 6.1
z | - \[May 26 6.1
Meera Mar eso eee | 3) EO. es 3a ss SS Ses5 TPE, ST 54
May 24 6.1
A CERTee 2 ee! 5b Sk a eee \<June 21 5.4
| | July 17 5.28

All plats were harvested the last of August. being plowed, topped,
and sold in the field. At this time average samples were taken from
each plat and tests made for sugar percentage and purity.

SEEDED MARCHII|| SEEDEDMARCH 27 |

WATER APPLIED; INCHES

0 | 105] 149] o | @12/ 1152] 1280]
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n= ae

Fic. 7.— Yield of sugar beets, seeded at two periods and irrigated with different quantities
of water.

The table following shows the results in yield, sugar percentages.
purity, and net returns per acre. These results are illustrated in
figure 7, the yields and corresponding amounts of water apphed
being shown.

——

IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. ed |

Yield of sugar beets and perecntage of sugar content and purity.

Yield Value at} Cost of

| Purity $5 per | irriga-

| |
: Number Number of Sugar
Seeding. : | sa ge Depth. 2 zi :
of plat | irrigations. | content. | Ee acre. an tion
|
Inches. | Per ceni.| Perceni.| Tons.
HI PNONGE soaaee ese sola sane 21.3 88.13 10.85 eee SR Be ee
Martie. 22) Gul Oners-2 222 10.5 | A I ey (eed 80.96 | 13.80 69.00 | #.10
| id ae nee ert 14.9 | .165 |. 81.44} 1750), 87.50| —5.81-
Ee INONC 22ea 3 S| eee 23.00 | 83.14 | 4.35 PRON WEE oa eae
Mar. 2 2 OnGs.< 822 6.12 | 20.10 | 83.75 6.7 33.50 2.38
a as ai Pa a (A eee ate 11.52 | 17.25 $3.89 14.75 73. 75 4.49
Zi Ved 2) 11 3 5s tee eee 17.80 16.85 89.91 18. 60 93. 00 6

In irrigating, continual attendance was necessary at a cost of 25
cents per acre-inch. Power cost 14 cents per acre-inch. The total
cost is therefore 39 cents per acre-inch.

With the same number of irrigations heavier yields were obtained
by early seeding than by late seeding. The results show an increase
in yield of 6 tons per acre from the unirrigated plats in favor of the
early plantang, while the plats given one irrigation show an increase
of 7.10 tons per acre. This is due entirely to the weather conditions
following seeding. Between March 12 and 15, 1.13 inches of rain
fell, giving the early seeding a vigorous start. Following this no
more rain fell until April 10, and the late seeding was very slow in
sprouting, some of the seed not coming up until the middle of April,
after the early seeded plats had been thinned.

In general the sugar percentage decreased with the increased
amounts of water added, although in every case this decrease was
overbalanced by the increase in yield.

The time of irrigation and the quantity of water required will
always depend upon the local conditions. This is shown very clearly
in the yields from plats 2 and 3, on which a second irrigation of 5.4.
inches, costing $2.10 per acre, increased the yield 120 per cent and the
gross returns $40.25 per acre. Here, as in other irrigated crops, suc-
cess or failure lies in the judgment of the irrigator in applying the
water.

WASHINGTON : GOVERNMENT PRINTING OFFICE : 1913

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Full text of "Progress report of cooperative irrigation experiments at California University farm, Davis, Cal., 1909-1912"

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