48
Effects of Foliar-Applied Methanol on Potato Yield and Quality
K.A. Rykbost, R.L. Dovel, and J. Maxwell s
INTRODUCTION
Repeated foliar applications of methanol have been reported to increase yields,
hasten maturity, and improve nutrient and water use efficiency in C3 plants under
conditions of high temperatures and high light intensity in Arizona. Widely
publicized in the popular press, preliminary findings have generated considerable
interest in the research community, but also among many commercial producers in
Oregon, Washington, and California. If preliminary findings are valid and can be
demonstrated to apply to climatic conditions prevailing in the Klamath Basin, the
use of methanol on high value crops would be beneficial for water conservation, and
as a possible remedy to production limitations imposed by short-season climatic
conditions. However, if this technology is not applicable under local conditions, or if
the preliminary reports are unfounded, evidence to that effect will assist producers
to avoid inappropriate expenditures for non-beneficial practices.
Research was initiated at several Oregon locations to evaluate effects of
methanol on important crops under a range of climatic and geographic conditions.
Trials with potatoes were conducted at Klamath Falls, Madras, and Ontario. Results
from Madras and Ontario will be reported in other publications.
PROCEDURES
Russet Burbank potatoes were planted at 12-inch seed spacing in 32-inch rows
on June 3. Standard cultural practices were followed (see page 26). Four-row plots,
50 feet long were established in a randomized complete block design to
accommodate six treatments and four replications. Treatments included solutions of
0, 20, and 40 percent methanol with no surfactant, and solutions of 20, 40, and 80
percent methanol with 0.1 percent Triton X-100 surfactant. Solutions were applied at
20 gpa with a backpack sprayer. All treatments were applied between noon and 1:00
pm on July 18, July 28, and August 11. Maximum/minimum air temperatures
recorded at the KES weather station on these dates were; 70/40, 86/46, and 81/46
°F, respectively. Average monthly maximum and minimum air temperatures were 74
and 40 °F for July, and 69 and 40 °F for August. Potatoes from the two center rows
were harvested on October 5. Total weights were determined at harvest. Samples of
120 lb/plot were stored and graded to USDA standards in early November.
1
/ Superintendent/Professor, Associate Professor, and Biological Sciences Research
Technician, respectively, Klamath Experiment Station, Klamath Falls, OR.
Acknowledgment: The Oregon Potato Commission provided funding in support of
this project.
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RESULTS AND DISCUSSION
Foliar treatments did not produce visible effects on the crop canopy. Vines were
beginning to senesce at the time desiccant was applied, with no apparent maturity
differences between treatments. Methanol treatments did not result in significant
differences in any of the yield parameters or in specific gravity (Table 1). This result
was similar to observations in field studies conducted at Madras and Ontario.
The original report of crop responses to methanol was based on high light
intensity and high air temperatures typical for southern Arizona. The 1993 growing
season in Klamath Falls was cooler than normal. Air temperatures only reached 90
°F on four days in August and 3 days in September. Average temperatures in July
were about 7 °F below long-term averages. However, temperatures experienced in
Ontario were higher than would occur in the warmest season in the Klamath Basin.
Any crop benefits from methanol that may be obtained in the weather extremes of
the southwest, do not appear to apply to potatoes grown in the Klamath Basin or
other production areas of Oregon. Growers are advised that foliar application of
methanol to potatoes is unlikely to produce benefits greater than the costs of
application, and may actually reduce gross crop revenue.
Table 1. Effect of foliar applications of methanol on yield, tuber size, and specific gravity
of Russet Burbank potatoes at Klamath Falls, OR, 1993.
Treatment )
1
Yield U.S. No. is
4-6 oz 6-10 oz > 10 oz Total
Specific
Yield
Bs No.2s Culls Total gravity
1
136
86
31
252
64
10
15
342
1.084
2
118
102
37
256
78
14
14
361
1.086
3
112
97
33
242
72
9
13
335
1.085
4
117
88
30
237
78
13
17
344
1.084
5
127
103
27
257
72
16
23
368
1.084
6
121
112
37
269
76
14
20
380
1.086
Mean
CV (%)
LSD (0.05)
122
12
NS
98
21
NS
33
38
NS
252
13
NS
73 13
18 65
NS NS
17
89
NS
355
14
NS
1.085
1
NS
/ 1) 20 gal/A water applied on 7/18, 7/28, 8/11.
2) 20 gal/A, 20% methanol, 0.1% Triton X-100, applied on 7/18, 7/28, 8/11.
3) 20 gal/A, 40% methanol, 0.1% Triton X-100, applied on 7/18, 7/28, 8/11.
4) 20 gal/A, 80% methanol, 0.1% Triton X-100, applied on 7/18, 7/28, 8/11.
5) 20 gal/A, 20% methanol, applied on 7/18, 7,28, 8/11.
6) 20 gal/A, 40% methanol, applied on 7/18, 7/28, 8/11.