REV09416

• Permit No: C1982057
• IBM Index Class Name: Revision
• Doc Name: INTERNAL MEMO SENECA II-W PR2 ADEQUACY DRAFT NARRATIVE REGARDING POTENTIAL MATERIAL DAMAGE
• From: DMG
• To: LARRY ROUTTEN
• Type & Sequence: PR2
• Media Type: D
• Archive: No

Seneca II-W
Projected Crop Reduction

pecies

Yield
Decrease
B
( ercent) Predicted
Conduc-
Tivily
Ecw
(mmhos/
cm)
Salinity
Threshold
Aw
(mmhos/
cm)

Relative
Yield
Y
(percent)

asture
Composition
(percent)
~
Crop
Reduction
(percent)
LOWER PASTURE

Intermediate Wheaterass MT 0 31 0
Luna Wheat ass MT 0 12 0
Hi¢hcrested Wheat ass MT 0 12 0
S.Brome 13.2 2.0 1.3 90.8 2l l.9
Orchard-
Grass
9.3
2.0
I.0
90.7
12
1.1
Perennial
R e rass
11.4
2.0
3.7
119.9
12
0

Lower Pasture Pro'ected Total Cro Reduction 3.0

UPPER PA STURE

Alsike
Clover'' 12.2
(I olito)
2.0 l.3
(I olito)
91.5
25
2.1
18
(Maas)
2.0 1.0
(Maas)
82
4.5
Timoth 13 2.0 1.3 81.2 25 4.7
S. Brome 13.2 2.0 1.3 90.8 25 2.3
Luna Wheat- ass MT 25 0

U er Pasture Pro'ected Total Cro Reduction
Usin I olito Values for clover 9.1
Usin Maas values for clover 11.5

' The DMG has also found another published value for the Alsike Sweetclover presented
in a table on the U.S. Salinity Laboratory Homepage. The table is titled "Relative Salt
Tolerance of Herbaceous Crops (Maas, 1990 (a)). In the calculations below, the yield
reduction for the upper field has been calculated using both the numbers presented in
Ippolito's paper and the 1990 Maas numbers.
One additional comment for species rated moderately tolerant, but for which no
specific threshold values are published, the percent yield decrease is estimated to be zero.
This estimate is based on the article "Crop Salt Tolerance -Curren[ Assessment" by
Maas and Hoffman (1977). This article categorizes crop species accordins the tolerance
level. A moderately tolerant species may show evidence of decreased yields at an ECe of
3.0 mmhos/cm. D!vIG agrees that using a 0 crop reduction value is acceptable for
moderately tolerant and tolerant species.