Potato Irrigation

well-wintered cows than from the lowwintered cows. The larger steers at
weaning gained about 5 pounds more between weaning and slaughter than did
the lighter weaned steers.
5 When home raised feed is available,
we recommend wintering cows on a full
maintenance ration of about 30 pounds
of com silage and 10 pounds of hay, or
the equivalent in other combinations.
However, if feed is scarce and abnormally high in price, we believe a stockman
can safely winter his cows on 75 percent
of the above daily rations for at least S
winters without serious ill effects in the
herd.
A WILLISTON EXPERIMENT STATION REPORT ON
Potato Irrigation
• By Howard Olson and R. H. Johansen
Since 1941, potato variety trials have dition when wet or dry. They do posbeen grown under irrigation and dryland . sess a high water holding capacity and
conditions at the Williston experiment tend to remain wet for considerable
stations. The irrigation station, estab- periods following irrigation or rainfall.
lished in 1939, is situated on the Lewis This is an advantage in reducing the need
and Clark Ir:r:igation project and the dry- for frequent water applications but it
land station is 5 miles west of Williston makes weed control difficult and dison typical upland Willi;ims soils. The courages late season irrigation, for the
dryland data were obtained from two dif- soil remains too sticky for efficient operferent locations, as before 1955 the sta- ation of potato harvesting machinery.
tion was adjacent to Williston.
Two types of irrigation studies with
Precipitation is the main factor limit- potatoes are reported here. One has
ing crop yields in this area with a mean been a continuous evaluation of potato
of 9.86 inches during the period of April varieties and selections from the Hortito August.
culture Department, North Dakota AgriThe irrigated trials were conducted on cultural Experiment Station at Fargo,
soils of the Havre series. ranging in tex- when grown under irrigation and under
ture from silty clay loam to silt loam dryland conditions. The other was an irtypical of the Missouri river bottom. rigation water requirement study carried
These soils are not particularly suitable out over a 6-year period (1948-1953) to
for gqod potato production due to poor determine when and how much to irriinternal drainage, and poor physical con- gate potatoes on Missouri river bottom
soils.
Howard Olson is Superintendent, Williston
Experiment Station.
R. H. Johansen is assistant horticulturist,
North Dakota Agricultural Experiment Station, Fargo.
Performance of Potato Varieties
·Under Irrigation
The amount and distribution of rain·
23
fall during the growing season determined the irrigation schedule. The prospect of rain was also an important factor. Irrigation was sometimes delayed
to minimize the hazard of excessive water which generally occurs when heavy
rainfall follows irrigation. Excessive
water on land with good surface and subsoil drainage is not serious, but on these
soils water-logging occurs readily and is
a constant hazard.
During the 14-year irrigation period,
the potato trials under irrigation received 31 water applications. One application was made in 3 of the years, 2 in 5
of the years and 3 times in 6 of the years.
The potatoes were irrigated 13 times in
July, 9 in August, 7 in June and 2 times
in May. Frequently a final irrigation,
even when needed, was intentionally
omitted to provide proper harvesting
conditions.
Land preparation before planting in- .
eluded fall plowing, with cultivation and
levelling in the spring. This practice of
spring cultivation and jevelling frequently dried out the soil sufficiently to
delay emergence of potatoes unless irrigation or rainfall followed planting. Consequently, during the past 3 years (19.551957), the land was levelled and irrigated in the fall and teceived a light harrowing in the 'spring.
No fertilizers were used in these trials
prior to 1953' but since then sideband applications at planting time were made
annually. Application rates varied from
200 to 350 pounds per acre of 33.5-0-0 or
20-20-0, depending on the previous history of the field. These rates were calculated to maintain high or ,maximum
levels of fertility and may not have b.een
the most economical.
The potato variety trials grown under
irrigation and under dryland conditions
24
were planted in blocks of 4 replicates
with 25 plants of each variety per block.
Although there were variations, the average spacing was 38 inches between
rows and 14 to 15 inches in the row. The
average planting date was May 19, but
the trial was planted as early as May 7
and as late as June 5. Generally, the
trials were harvested in the latter part
of September. The harvested potatoes
were weighed, graded and determinations were made for total yield, marketable yield, specific gravity and general
quality. Tuber maturity and scab readings were al~o recorded in some years.
Although these variety trials were
carried out for 14 years, for all practical
purposes only the variety trial data record.ed from 1950 through 1957 were
considered, and only for those varieties
or selections that were included in the
trials for 3 or more years.
Table 1 shows the total yields in
bushels per acre of 11 varieties ~nd
selections grown under irrigation and under dryland conditions in the 8 years
1950-1957. In comparing the 8 year average of irrigated versus dryland total
yields, irrigation resulted in an increase
of 191.3 bushels, or 56 percent, over the
dryland yields. The average increase in
any year. varied from 301.3 bushels per
acre in 1956 to 22.6 bushels per acre in
1950. The smallest differen.ce.s occurred
in years of above normal precipitation
(1950, 19.52 and 1954). All dryland production was on land that was summerfallowed the previous year. Therefore,
twice the acreage was required to produce the dryland yields.
An varieties did not respond to irrigation in the same way. Of the varieties
grown in these trials for 6 or more years,
Early Gem showed the best response with
an average increase in total yield of 276
·Table 1. TOTAL YIELD IN BUSHELS PER ACRE OF POTATO VARIETIES GROWN UNDER IRRIGATION AND NON·
IRRIGATION AT WILLISTON
1950
Variety
I.
Irish Cobbler .. ···········-··············
Red Pontiac ..............................
Early Gem ....................................
Norland· ..........................................
Nordak .............................................
Norgleam ····································
Triumph .......................................
Kennebec ....................................
Redkote .............•....................•.......
ND 457-1 ··········•····························
. Mano ta .............................................
Average ···--- ......................
I.-Irrigated.
~
321
436
1951
N.I.
I.
288
360
283
381
293
1952
N.I.
I.
131
149
112
342
42.6
380
329
441
334
487
271
373
146
146
371
316
302
122
380
357
317
134
392
429
386
307
353
377
N.I.
277
377
253
285
361
330
248
280
301
I.
1953
1954
N.I.
I ..
188
263
164
602
562
499
259
344
210
369
201
575
574
536
240
269
369
389
386
411
201
190
197
201
455
316
544
463
236
349
455
464
447
I.
N.I.
280
1955
N.I.
I.
1956
513
378
457
202
143
199
474
378
181
189
727
532
574
518
501
538
392
432
164
180
565
1957
N.I.
I.
N.I.
344
177
278
265
469
408
664
381
359
351
162
201
205
227
170
164
264
246
272
214
407
147
182
Average
I.
N.I.
412
490
456
471
484
475
402
414
403
342
378
430
218
280
181
235
215
215
243
331
281
219
205
238
N.1.-Non-Irrigated.
Table 2. SPECIFIC GRAVITY OF POTATO VARIETIES GROWN UNDER IRRIGATION AND NON-IRRIGATION AT
WILLISTON.
Variety
I.
Irish Cobbler ............................ 96
Red Pontiac ······························ 89
Early Gem ....................................
Norland ··········································
Nordak .............................................
Norgleam .....................................
Triumph ······································· 92
Kennebec ....................................... 97
Redkote ··········································
ND 457-1 ....................................... 101
Mano ta ..........................................
Average .............................. 95
1950
N.I.
102
83
1951
I.
N.I.
I.
83
78
82
88
81
86
77
60
69
93
88
75
79
70
58
97
ff7
81
93
80
70
1952
. N.I.
I.
90
69
94
84
77
84
94
91
85
81
70
76
80
71
74
74
85
71
85
80
78
90
87
89
86
71
80
84
91
91
93
96
ff7
98
95
89
92
74
1955
1954
I.
84
86
82
90
1953
N.I.
N.I.
83
80
75
77
75
82
'19
N.I.-Non-Irrigated.
!.-Irrigated.
First 2 digits in specific gravity readings were dropped. For example 89 would read 1.089.
1956
I.
N.I.
I.
N.I.
72
75
79
69
68
77
75
79
77
86
79
83
84
85
81
77
82
74
76
83
89
84
I.
1957
83
65
76
68
77
77
N.I.
99
80
87
84
96
96
Average
I.
N.I.
86
75
79
75
78
78
78
83
84
86
78
80
75
79
84
69
74
91
92
91
82
82
89
75
77
81
90
87
80
68
80
89
88
83
bushels per acre, as compared with Red ferences occurred with Early Gem, TriPontiac with an average increase of 209 umph, Nordak and Norgleam. The 8bushels per acre.
year average specific gravity for Red
It can also be seen (Table 1) that early Pontiac was the same under irrigation
maturing varieties generally showed bet- and dryland conditions, but much variater responses to irrigation than late ma- tion occurred within years.
turing varieties. Early maturing variWhen potatoes were irrigated late in
eties form and develop most of their the season, maturity was delayed, caustubers during July and August as com- ing immature skin and poor quality
pared with August and September for tubers. The number of rough and overlate maturing varieties. Since water ap- size tubers was also increased. However,
plications were made most frequently in late fall irrigation of land to be cropped
July and August, this period appears to potatoes was beneficial to the crop the
critical, particularly with early maturing following year. This may not be as significant ·on coarser textured soils with
varieties.
When fertilizer was first applied to the lower water holding capacity.
irrigation trials in 1953 and continued
Water Requirement Studies
through 1957 a marked increase in yield ·
for Potatoes
was noted during this period. The ·averStudies were carried out 6 years (194S:
age yield under irrigation without fer1953)
to determine the frequency and
tilizer (1950-52) was 358 bushels per
amount
of irrigation water required by
acre, compared with 456 bushels per
potatoes
grown on the Missouri river botacre in the period 1953-57 when fertiltoms.
The
Pontiac variety was used in
izers were used.
·
·each year, except in 1948 when Cobbler
Specific gravity is a convenient meas- was used. Fertilizers used were 350
ure of solid or dry matter content of pounds per acre of 0-45-0 in the years
potatoes and is usually associated with 1949-1951 and 425 pounds per acre of ,
texture or mealines~ of the potato.
10-32-0 in 1952 and 1953. No fertilizer
The 8-year average specific gravity of was used in 1948.
potato varieties and selections grown unThree different moisture levels were
der irrigation and· under dryland condi- established. The low moisture plots
tions at Williston was 1.082 and 1.083, were to receive only enough watet to esrespectively (Table 2). This was not sig- tablish a stand; the medium moisture
nificant, ·but great differences between plots to receive 1 irrigation during the
years arid between varieties did . occur. season and the high moisture plots to
The use of fertilizer in the irrigated plots receive 2 or more irrigations depending
during the period 1953 to 1957 resulted upon the season.
in decreases in specific gravity, as comYield data.showed good correlation be- 1
pared with that in irrigated plots with no .tween the amount of irrigation water apfertilizer before 1953.
plied and the total yield (Table 3). The
The variety Irish Cobbler showed the high moisture plots produced the highest ~
least ·variation witli~n years in specific average total yield for the 6 years with 1
·gravity when grown under irrigatibn or 457 bushels _per acre. The low moisture
dryland ·conditions: Relatively small dif- plots received. irrigation water in 1952
26
Precipitation was also a factor, since in
2 of· the 6 years this was above normal
Although irrigation during the growing
season did result in increased yields, the
factor of stored soil moisture· makes it
difficult to appraise the true value of
seasonal irrigation on potato production.
·and 1953 only, yet the mean yield was
. relatively high with 365 bushels per acre.
Since the whole plot area was fall irrigated, it is apparent that the available
moisture in the root zones was at a sufficiently high level during the following
crop season to maintain reasonable plant
growth.
Table 3. THE EFFECT OF MOISTURE LEVELS ON POTATO PRODUCTION AT
WILLISTON IRRIGATION STATION (AVERAGE OF 6 YEARS).
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High moisture level ................. ........
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U.S. No.1
yield
Total
yield*
365
13.7
295
403
332
457
378
*Yiela in bushels per acre.
MARKET PRICE OF SHEEP AND LAMBS
DOLLARS
PER CWT
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