57
Foliar Fertilization of Russet Burbank Potatoes,
Klamath Experiment Station, 1988
K. A. Rykbost and J. Maxwell'
INTRODUCTION
Soil and plant analysis data suggest that a portion of the mineral
soils used for potato production in the ,Klamath Basin are marginally
deficient in boron and zinc. These nutrients can be provided from several
commercially available sources, some of which have been evaluated in
research in other areas of the Northwest.
This experiment was established to evaluate the nutrient status of
Russet Burbank potatoes grown on soil low in zinc and boron, and to
determine whether foliar fertilization would correct nutritional imbalances
or affect yields or quality.
PROCEDURES
Russet Burbank potatoes were planted at 12-inch seed spacing in 32inch rows on May 25.
Fertilizer included 650 lbs/A 16-20-0-13 banded at
planting and 100 lbs N/A as solution 32 applied on June 7.
Standard
cultural practices were followed (page 14).
A hand-held plot sprayer was used to apply foliar fertilizers to fourrow plots, 40 feet long. Four replications included eight treatments (Table
1) in a randomized complete block design. All fertilizers were applied at
30 gpa of solution.
The crop was frost-killed on September ,13 and potatoes were harvested
on October 10. Harvest areas were the two center rows, 37 feet long. Total
plot weights were determined in the field. Approximately 60-pound samples
were saved from each plot for grading in mid-November. Crop values were
calculated using prices described in the previous experiment (page 14).
1/ Superintendent/Associate Professor, Experimental Biology
Technician, respectively, Klamath Experiment Station.
Acknowledgements: Partial funding by the Cooperative State Research Service
and the Oregon Potato Commission, and petiole sample analysis by the Leffingwell Company, contributed to this research project.
58
RESULTS AND DISCUSSION
Soil samples collected prior to planting indicated P and K levels were
very high. Zinc at 0.5 ppm, and boron at 0.6 ppm, were in the low to very
low range. The soil pH was 5.9 and organic matter content was 0.6 percent
in fine sandy loam.
Petiole samples were collected on August 8 and September 6 (Table 2).
Foliar fertilizers did not produce observable differences in vegetative
development. Vine growth appeared vigorous until frost occurred.
Petiole nutrient levels did not respond to foliar fertilizers. In all
Zinc
cases, nutrient levels were within sufficiency ranges on August 8.
levels were on the low end of the sufficiency range on September 6, but were
unaffected by zinc fertilization. Boron levels in petioles were in the
sufficiency range with no differences between treatments.
Zinc-sulfate (36 percent Zn) reduced tuber size, yield, and specific
gravity (Table 2). Total yield of No. l's was significantly lower for this
treatment than all treatments except the control. While foliar toxicity
symptoms were not observed, crop performance data suggest toxicity may have
occurred. Solubor (20 percent B) did not affect crop performance.
All treatments which included Nutra-Phos 24 increased the yield of No.
l's compared with the control. Nutra-Phos 24 and Sorba-Spray Ca was significantly higher than the control in total yield of No. l's. Costs
ranging from approximately $3/A for Solubor, to less than $20/A for all
others, were negligible in comparison to increases in crop value for all
additives except zinc-sulfate.
SUMMARY AND CONCLUSIONS
Neither zinc nor boron alone improved yields at quantities applied in
other regions where deficiencies have been documented. In smaller quantities, blended with other nutrients, small but economical yield responses
were obtained. Nutra-Phos 24 in combination with Sorba-Spray Ca increased
the yield of No. l's 63-cwt/A. Petiole analyses did not show responses in
plant nutrition to any of the foliar applications.
Similar yield responses to blended foliar fertilization products have
been observed elsewhere in the Northwest. These results are sufficiently
promising to justify further pursuit of this area of investigation.
59
Table 1. Rate and Timing of application of foliar fertilization
products applied to Russet Burbank potatoes, Klamath
Experiment Station, 1988.
TREATMENT
1
2
3
4
5
6
7
8
TIMING
PRODUCT
RATE/A
Water
Solubor
Zinc-sulfate
Nutra-Phos 24
Nutra-Phos Super K
Nutra-Phos 24
Sorba-Spray Ca
Nutra-Phos 24
Sorba-Spray CaB
Nutra-Phos 24
Sorba-Spray ZBK
Nutra-Phos 24
Sorba-Spray ZPK
30 gal.
1.25 lbs
1.4 lbs
5 lbs
5 lbs
5 lbs
2 qts
5 lbs
2 qts
5 lbs
2 qts
5 lbs
2 qts
7/14,
7/14,
7/14,
7/14
7/25
7/14,
7/14,
7/14,
7/14,
7/14,
7/14,
7/14,
7/14,
7/25
7/25
7/25
7/25
7/25
7/25
7/25
7/25
7/25
7/25
7/25
Table 2. Petiole nutrient levels in Russet Burbank treated with
several foliar fertilizers, Klamath Experiment Station,
1988.
TREATMENT
P
K
Ca
Mg
Zn
---
PPm
---
1
2
3
4
5
6
7
8
0.24
0.26
0.36
0.36
0.25
0.24
0.35
0.35
August 8
9.2
0.83
8.9
0.60
9.3
0.77
9.5
0.82
8.8
0.78
9.1
0.62
9.5
0.75
9.2
0.70
0.47
0.39
0.37
0.35
0.47
0.41
0.37
0.35
19
27
62
30
41
35
42
26
38
36
36
34
35
35
37
35
1
2
3
4
5
6
7
0.15
0.21
0.15
0.12
0.13
0.15
0.12
September 6
7.8
1.54
7.4
1.49
10.2
1.38
8.1
1.31
1.38
7.8
7.9
1.45
7.6
1.42
0.78
0.82
0.77
0.60
0.68
0.77
0.81
7
10
9
9
9
11
7
33
36
34
32
34
33
34
8
0.14
8.7
1.36
0.75
10
34
Table 3.
0
,..o
Effects of foliar fertilization on Russet Burbank, Klamath Falls, 1988
YIELD #1's
6-10 oz
>10 oz
cwt/A
TREATMENT
4-6 oz
1
2
3
4
5
6
7
8
142
130
131
170
178
140
164
157
124
129
97
118
153
138
140
141
16
36
23
NS
CV(%)
LSD(.05)
YIELD
CULLS
cwt/A
TOTAL
B's
#2's
27
37
18
31
24
31
21
24
292
296
246
318
355
309
325
322
84
80
112
103
90
79
106
87
14
13
10
14
5
4
9
6
19
2
4
4
5
8
7
13
60
NS
11
49
21
NS
67
NS
114
NS
TOTAL
408
390
372
439
454
400
447
428
7
44
VALUE
($/A)
2793
2912
2287
2963
3245
2953
3000
2955
SPECIFIC
GRAVITY
1.086
1.083
1.079
1.085
1.084
1.083
1.085
1.083
0.2
0.003