DWR_2807910

• Title: STATE AND DIVISION ENGINEER'S FORUM ENGINEERING ASSUMPTIONS - ATTACHMENT: CROP COEFFICIENT MEMO
• Author/Source: DEAN SANTISTEVAN, P.E.
• Author/Source: DIVISION OF WATER RESOURCES
• Keywords: CROP COEFFICIENT, CROP GROWTH
• Document Type - Reference Library: Presentations
• Document Date: 4/15/2014
• Year: 2014
• Team/Office: Division 1 Office

MEMORANDUM
December 13, 2013
Issues with Selecting an Appropriate Crop Growth Stage Coefficient for the SCS Mod. Blaney
Page 25 of 34

Alfalfa. The Task Memo 59.1 crop curve for alfalfa suggests that SCS TR
consumptive use. Findings from our study of ARS 1275 do not suggest the same. The coefficients from
Task Memo 59.1 present an unusual shape that is not bell shaped and
suspicious, as is the valley of the curve
suggest that the alfalfa may have a slightly higher peak, but it does not confirm the Task Memo curve.
The two peaks in Task Memo 59.1
months.
Figure 24 – Comparison of crop curves for alfalfa
Dry Beans. The Task Memo 59.1 crop curve for
consumptive use. Findings from our study of ARS 1275 suggest the same. The coefficients from Task
Memo 59.1 present an unusual shape

Figure 25 – Comparison of crop curves for dry beans

0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0
1
0
2
0
3
0
4
0
5
0
6
0
7
0
8
0
9
0
Cr
o
p

G
r
o
w
t
h

S
t
a
g
e

C
o
e
f
f
i
c
i
e
n
t
,

k
c
0
0.2
0.4
0.6
0.8
1
1.2
0 20
Cr
o
p

G
r
o
w
t
h

S
t
a
g
e

C
o
e
f
f
i
c
i
e
n
t
,

k
c
Issues with Selecting an Appropriate Crop Growth Stage Coefficient for the SCS Mod. Blaney-Criddle Eqn.
The Task Memo 59.1 crop curve for alfalfa suggests that SCS TR-21 will under
consumptive use. Findings from our study of ARS 1275 do not suggest the same. The coefficients from
Task Memo 59.1 present an unusual shape that is not bell shaped and the magnitude is of the peak
valley of the curve. Alfalfa values in Pochop, adjusted to 5,000’ above sea level, do
suggest that the alfalfa may have a slightly higher peak, but it does not confirm the Task Memo curve.
in Task Memo 59.1 curve may be the result of temperature effects during the shoulder
crop curves for alfalfa

The Task Memo 59.1 crop curve for dry beans suggests that SCS TR-21 will
ptive use. Findings from our study of ARS 1275 suggest the same. The coefficients from Task
Memo 59.1 present an unusual shape, although one that is somewhat bell shaped.
crop curves for dry beans
8
0
9
0
1
0
0
1
1
0
1
2
0
1
3
0
1
4
0
1
5
0
1
6
0
1
7
0
1
8
0
1
9
0
2
0
0
2
1
0
2
2
0
2
3
0
2
4
0
2
5
0
2
6
0
2
7
0
2
8
0
2
9
0
3
0
0
3
1
0
3
2
0
3
3
0
Day of Year
SCS TR-21
Average of ARS 1275
Task Memo 59.1
Adj. Pochop
20 40 60 80
Percent of Growing Season
SCS TR-21, dry beans
Santa Barbara, CA
Task Memo 59.1
Criddle Eqn.
21 will under-estimate
consumptive use. Findings from our study of ARS 1275 do not suggest the same. The coefficients from
the magnitude is of the peak is
Alfalfa values in Pochop, adjusted to 5,000’ above sea level, do
suggest that the alfalfa may have a slightly higher peak, but it does not confirm the Task Memo curve.
may be the result of temperature effects during the shoulder

21 will over-estimate
ptive use. Findings from our study of ARS 1275 suggest the same. The coefficients from Task

3
2
0
3
3
0
3
4
0
3
5
0
3
6
0
100