Figure 1. The influence of seeding rate on the yield and
yield components of Grandin HRSW.
North Dakota State University
North Dakota Experiment Station
NDSU Ag Report 1, April 2001
Bryan Hanson,
Hanson is agronomist, Langdon Research Extension Center
Introduction
Planting rate study
Yield, test weight, and protein
Yield components
Other agronomic traits
Established plant stands vs. yield
Using the correct planting rate for hard red spring wheat (HRSW) (Triticum aestivum) is critical to establishing plant stands that ensure optimum yields.
Optimum planting rates for HRSW vary across North America spring wheat growing regions. In southeastern Saskatchewan, a planting rate of 18-36 pounds per acre was adequate where yields are less than 20 bushels per acre (Pelton, 1969), while in Alberta, where yield levels range from 38 to 51 bushels per acre, a planting rate of 90 pounds per acre gives optimum wheat yields (Guitard et al., 1961). Under irrigation in Utah, where yields ranged from 60 to 80 bushels per acre, a rate of 50 to 60 pounds per acre was adequate except when planted late (Woodard, 1956). In western North Dakota at Minot, Williston and Dickinson, HRSW wheat yields were optimized at a stand rate of 1 million plants per acre at yield levels of 30 to 35 bushels per acre (Riveland et al., 1979).
Many of the previous studies cited in literature were conducted a number of years ago with older varieties while much of the research on HRSW planting rates in North Dakota has been conducted in dryer environments. The objectives of this planting rate study conducted by the Langdon Research Extension Center were to i) evaluate planting rate effects on yield, yield components and other agronomic traits, and ii) study the relationship between established plant population and yield to determine the minimum number of plants per square foot needed to obtain optimum yields of HRSW in the high-yield environment (45-60 bushels per acre) of northeastern North Dakota.
Grandin HRSW was planted at a total of 16 locations across northeastern North Dakota from 1991 to 1993. Precipitation totals for May through August were above normal at all locations in 1991 and 1993 and below normal in 1992 (Table 1). Small grain growing degree-days for May through August at Langdon were 177 degree-days above normal in 1991 and 500 and 397 degree-days below normal in 1992 and 1993, respectively. Four planting rates, adjusted for percent germination and seed size, of 0.5, 1.0, 1.5 and 2.0 million seeds per acre were used (Table 2). Trial design was a randomized complete block with four replications. Seed treatment was carboxin 17F + thiram 17 at 3 fluid ounces per hundred pounds of seed. Weed control was excellent throughout the study.
Table 1. Trial locations, planting and harvest dates, soil series, previous crop, yield goal and growing season
rainfall for HRSW planting rate studies across northeast North Dakota, 1991-1993.
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Growing Season
Trial Planting Harvest Soil Previous Yield -- Rainfall (May-Aug) --
Location Date Date Series* Crop Goal 1991-93 Normal
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bu/acre inches inches
1991
Langdon 25 April 21 Aug Svea Fallow 80 13.54 10.78
Cavalier 13 May 14 Aug Overly Wheat 50 12.89 11.14
Park River 26 April 13 Aug Glyndon Fallow 90 17.52 10.75
Tolna 23 April 6 Aug Svea Barley 70 12.57 10.98
Devils Lake 9 May 19 Aug Overly Wheat 85 17.39 10.21
Cando 9 May 19 Aug Glyndon Wheat 50 13.63 9.64
1992
Langdon 26 April 1 Sep Svea Fallow 80 8.80 10.78
Cavalier 7 May 16 Sep Overly Wheat 65 10.16 11.14
Park River 23 April 20 Aug Gardena Fallow 80 9.83 10.75
Devils Lake 30 April 23 Aug Bearden Wheat 70 6.21 10.21
Cando 30 April 27 Aug Glyndon Fallow 60 6.98 9.64
1993
Langdon 1 May 8 Sep Svea Fallow 80 22.18 10.78
Park River 30 April 4 Sep Glyndon Fallow 80 19.90 10.75
Petersburg 12 May 7 Sep Hamerly Sunflower 50 19.81 10.98
Devils Lake 8 May 28 Aug Glyndon Flax 80 20.80 10.21
Cando 12 May 17 Sep Glyndon Wheat 60 18.41 9.64
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* Soil Classification. Svea -- fine-loamy, mixed, Pachic Udic Haploborolls;
Overly -- fine-silty, mixed Pachic Udic Haploborolls; Glyndon -- coarse-silty,
frigid Aeric Calciaquolls; Gardena -- coarse-silty, mixed Pachic Udic Haploborolls;
Bearden -- fine-silty, frigid Aeric Calciaquolls; Hamerly -- fine-loamy,
frigid Aeric Calciaquolls.
Table 2. Grandin HRSW planting rate for trials
conducted in northeastern North Dakota, 1991-1993.
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Planting Rate*
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Million seeds/acre Seeds/ft2 lbs/bu bu/acre
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0.5 11 42 0.7
1.0 23 83 1.4
1.5 34 125 2.1
2.0 46 166 2.8
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* Planting rate reported as pure live seeds. Adjusted
for percent germination and seed size. Thousand
kernel weight = 38 grams (11,950 seeds per pound).
Stand counts were made in each plot after emergence to determine established
plant populations and percent emergence. Seven
6-inch spaced rows 16 feet long were harvested for grain yield with a plot combine.
Results were analyzed treating individual locations
and years as separate environments.
Significant environment by planting rate interactions for yield, test weight, lodging, plant height and days to head were observed (Table 3). Upon inspection, it was determined that the significance was due to differences in magnitude of responses and not a change in rank due to planting rates, so the data are presented as averages across environments.
Table 3. Analysis of variance for yield, yield
components and other agronomic responses on Grandin HRSW.
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Source
--------------------------------
No. of Planting Environment
Environments Rate (PR) (E) PR x E
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Yield 16 ** ** **
Test weight 16 ** ** **
Protein 16 NS ** NS
Plant height 16 NS ** **
Lodging 6 ** ** **
Days to head 8 ** ** **
% Emergence 16 ** ** NS
Tillers/plant 16 ** ** NS
Heads/ft2 16 ** ** NS
Spikelets/head 16 ** ** NS
Kernels/spikelet 16 ** ** NS
1000 KWT 16 NS ** NS
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** Indicate significance at the 0.01 level of probability.
NS indicates non-significant.
Yields across the 16 environments ranged from 27.0 bushels per acre at Devils Lake in 1993 to 75.7 bushels per acre at Cando in 1992, with an average yield of 51.7 bushels per acre. The 0.5 million seeds per acre planting rate yielded an average of 6.3 bushels per acre less than all other planting rates and was the lowest yielding in 15 of the 16 environments. Yields from the 2.0 million seeds per acre planting rate were 1.9 bushels per acre higher than yields from the 1.0 million seeds per acre planting rate. There was not a significant yield difference between the 2.0 and 1.5 million seeds per acre planting rate (Table 4).
Table 4. Planting rate effect on yield, test weight
and protein of Grandin HRSW across 16 environments
in northeast North Dakota, 1991-1993.
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Planting Rate Yield Test Weight Protein
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million seeds/acre bu/acre lbs/bu %
0.5 46.9 58.3 14.8
1.0 52.2 59.1 14.8
1.5 53.2 59.3 14.8
2.0 54.1 59.5 14.9
LSD 5% 1.6 0.4 NS
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--------------------------------------------------
Test weights averaged 60.0 pounds per bushel in 1991 and 61.0 pounds per bushel in
1992, while the 1993 test weight averaged 58.4 pounds per bushel. Test weight averaged
1.0 pound per bushel lower for the 0.5 million seeds per acre planting rate compared to
the higher planting rates and was the lowest in
13 of the 15 environments. Lower yields and test weights in 1993 resulted from
fusarium head blight (Fusarium graminearum) infections.
Percent protein did not differ with planting rate.
Yield components were determined from a 3-foot hand harvested row taken from each plot before harvest. Effects of planting rate on yield components are given in Table 5. Tillers per plant (which formed a head), spikelets per head, and kernels per spikelet were highest at the 0.5 million seeds per acre planting rate and decreased as planting rate increased. Established plants and heads per square foot were highest at the 2.0 million seeds per acre planting rate and decreased as the planting rate decreased. Planting rate did not affect 1000 kernel weight. Similar yield component trends have been observed in other studies (Pelton, 1969; Guitard et al., 1961, Riveland et al., 1969).
Table 5. Planting rate effects on yield components of Grandin HRSW across 16 environments in northeast
North Dakota, 1991-1993.
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----- Planting Rate ----- Established 1000
Million Seeds Plants Plants Heads Tillers Spikelets Kernels Kernel wt.
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/acre /ft2 /ft2 /ft2 /plant /head /spikelet grams
0.5 11 10.7 49.0 4.6 12.5 2.0 34.9
1.0 23 18.7 56.6 3.1 12.0 1.9 35.0
1.5 34 24.8 57.1 2.4 11.6 1.8 35.0
2.0 46 30.8 60.1 2.1 11.3 1.8 35.4
LSD 5% 1.9 3.4 0.2 0.3 0.06 NS
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The response of yield and yield components
to planting rate as a percentage of the mean
for each trait is shown in Figure 1. Plants per square foot had a strong positive response
to planting rate while tillers per plant had
a strong negative response.
Figure 1. The influence of seeding rate on the yield and
yield components of Grandin HRSW.
The effect of planting rate on plant height was non-significant. Lodging scores at the six environments where lodging occurred were the lowest at the 0.5 million seeds per acre rate and increased as planting rates increased. The number of days to heading from planting date was highest at the lowest planting rate and decreased as planting rates increased. Percent emergence was highest at the lowest planting rate (Table 6). Lower percent emergence at higher planting rates may have been due to increased seed competition within the row. This same effect as been seen in other small grain planting rate studies (Hanson and Lukach, 1992, 1993).
Table 6. Planting rate effect on agronomic traits of
Grandin HRSW across several environments in
northeast North Dakota.
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Plant Days to
Planting Height Lodging Head Emergence
Rate (16)* (6) (8) (16)
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million seeds/acre inches 0-9** from planting %
0.5 36.5 0.1 57.3 94.8
1.0 36.6 0.4 56.5 88.0
1.5 36.7 1.2 56.0 85.3
2.0 36.5 1.9 55.8 84.9
LSD 5% NS 0.9 0.5 4.4
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* Number of environments observed.
** 0 = plants stand erect, 9 = plants flat on ground.
The relationship between established plant stand and yield was analyzed in this study to help determine the minimum number of plants per square foot needed to obtain optimum yields. The optimum yield in this study occurred at 34 plants per square foot (1.48 million plants per acre) with no significant difference in the range between 26 and 41 plants per acre) (Figure 2). This suggests that the minimum number of established plants to obtain optimum yields would be 26 plants per square foot. No significant yield benefits would be obtained with higher established plant stands.
Figure 2. Relationship between plants/ft2 and yield of Grandin HRSW
averaged across 16 environments in northeast North Dakota, 1991-1993.
A producer's goal, then, is to select a
planting rate that establishes a plant stand of at least
26 plants per square foot. Percent emergence
is unpredictable due to a variety of factors such as depth of planting, potential soil
crusting, seedling diseases, dry seedbeds and
herbicide injury. These factors can result in large
differences in percent emergence that can
occur from field to field, which makes selecting the best planting rate difficult.
In this study, the average percent emergence of the 1.0, 1.5 and 2.0 million seeds per acre planting rate at 16 environments was 86 percent. To obtain an established plant stand of 26 plants per square foot, a producer should use a planting rate between 1.25 and 1.40 million pure live seeds per acre assuming a 10-20 percent reduction in stand. Anticipated stand losses of greater than 10-20 percent would require further adjustments to planting rates.
Guitard, A.A., J.A. Newman, and P.B. Hoyt. 1961. The influence of seeding rate on the yield components on wheat, oats, and barley. Canadian Journal of Plant Science. 41:751-758.
Hanson, B.K. and J.R. Lukach. 1992. Barley response to planting rate in northeast North Dakota. North Dakota Farm Research. 49(5): 14-19.
Hanson, B.K. and J.R. Lukach. 1993. Semi-dwarf durum response to planting rate in northeast North Dakota. North Dakota Farm Research. 49(6): 6-12.
Pelton, W.L. 1969. Influence of low seeding on wheat in southwestern Saskatchewan. Canadian Journal Plant Science 74:33-36.
Riveland, N.R., E.W. French, B.K. Hoag, and T.J. Conlon. 1979. The effect of seeding rate on spring wheat yield in western North Dakota -- an update. North Dakota Farm Research. 37(2): 15-20.
Woodard, R.W. 1956. The effect of rate and date of
seeding of small grains. Agronomy Journal. 48:160-162.
NDSU Ag Report 1, April 2001
NDSU is an equal opportunity institution
North Dakota State University
North Dakota Experiment Station