12 BULLETIN 499, U. S. DEPARTMENT OF AGRICULTURE. 
TasLe 1V.—Average total percentages of soil moisture to a depth of 38 feet in 
the Victoria grove, California, in 1915. 
{Notr.—The first four treatments were not irrigated between April 22 and June 10. The last six 
treatments were irrigated on May 20.] 
Dates of sampling before and after irrigation. 
Soil treatment. After, |Before,| After,|Before,| After, |Before,| After, |Before,| After, |Before, 
Apr. | June | June| July | July | Aug. | Aug. | Sept. | Sept.| Oct. 
22. 10. 22. 12. 26. 12. oe 13. iis 12: 
Alfalfa: 
ae 
ous 
it 
2 Same. plusiimess== ssesse- 17.9 
Manure: 
Set et 
— 
“1 00 = © 
SoS et GIES go tS) 
Sane, plus lime == 22-2. =-- Weed 
Sweet clover: 
CONCTICLODieeeeese cee =o ee leone 
Same plusuim C2 se. seers eee eee 
Barley: 
COVETICLOD ee iste secs aes | eer 
Sian; OMS WWI. See ebSeccleccuuse 
Warepilhan enrol esas sooo clues deo cllacouece 
SS AN we 
(cael el dl oe 
bo or 
fot ft 
rN 
wo 
. Ve" 
RO 
Nekor) 
bh et 
Ne ate CE enteral © SSIS) 
H O10 & — oo ©100 
oo 
Phe IC Sipe (AS) 
OwWh > forKor} Oe “IO1 
woo oo re ho = o> 
= 
1 Basined. 
Tt is apparent from Table IV that the greatest reduction in mois- 
ture took place under the cover crops, the loss being greater than 
from the uncultivated row. This is brought out more clearly in 
Table V, which gives the amount of available moisture in the sur- 
face 3 feet of soil before irrigation, the critical moisture period. 
This table shows that the mulched-basin system is the only one that 
retained available moisture at all times. In all the other treatments 
the moisture content at some time during the summer was reduced 
below the wilting coefficient. This deficiency in the moisture supply 
in the case of the cover-crop tests was also shown by the appearance 
of the trees, which wilted badly during the summer before the 
irrigation periods came around. 
TABLE V.—Average perceniages of available soil moisture to a depth of 3 feet, 
before and after monthly irrigations, in the Victoria grove, California, in 
1915. 
Before monthly irrigations. After monthly irrigations. 
Soil treatments. 
June | July} Aug. | Sept.} Oct. | Aver-} Apr. | June} July | Aug. | Sept. 
10.1 ID- 13% 13 12. | age. | 22. Vee 26. 20. Wie 
Alfalfa: 
STN ASTIN S beep cere 4.7 4A Sisal 1.8 74D 2.8 7.8 ie 6.2 7.4 5.8 
Samer pluslimenyee =-ee eee ee 4.4 2.9 35a) 3.8 4.1 Bb U 9.0] 7.4 9.7 9.7 9.0 
Manure: 
IETS ASHTIG) & rae a eyo pe eae gat el .9 Bil Hos 3.2 1.8 6.5 4e2a4) 18-9 9.1 8.3 
Names sp lusdim Caesars -8 ial 2.8 BO | Bes 2.0 8.0 Seon |e OnO 8.1 10.4 
Sweet clover: : 
COVEMCLODE tee eee ee 5.0 |—1.0 |—2.4] () ]...... On| Biseer ee GH 2H Sl Go iA) leemece 
Samespluslimenae seen res 4.5 |— .4 ;—3.0] (@) |-..... pi el esate S59R rosea) in lesetere 
Barley: 
OOS GO) DS s6asssesccccocdaser Bah l=—scten lan Cy liseooealneedee lige sles 222 Neate | ee 
Same lus lim Ceeaee seer 324 |==2. 65 (2) les eecaleemees SAS lean 1A ik (2) sil arses erase 
UWinculifivate digas s ee  eee 5.8 -4 |—2.0 |— .7] ©) AQ in| seacwitinte aver ele a Geisler) 
Same-splusiime ss. see ee epee 4.3 -6 5U 9] ©) TAG se ast 2.4] 3.0] 5.1} @) 
1 ae jest previous irrigation of basins was given on April 22; other treatments about May 20. 
2 Basined, 
