Planting the 2017 winter wheat crop

Profitable wheat production begins with timely planting and practices that help insure a uniform population of seedlings this fall.

Planting the 2017 winter wheat crop

Much of wheat’s yield potential is determined at planting. To attain top yields, measures need to be taken to plant early and achieve an even and uniform stand of seedlings.

Planting date

Early planting contributes significantly to improved yields. This was demonstrated a year ago when not only were many fields planted during September, but warm weather allowed wheat to develop late into the fall, leading to well-developed root systems and tillers. Generally, beginning in mid- to late September, potential wheat yields slip at least 1 bushel for every day planting is delayed. This relationship does not hold once the calendar reaches late October as soil and weather conditions tend to play a more important role.

While the Hessian fly no longer poses a significant threat to wheat in Michigan, the fly-free-date is still a useful reference (see Hessian fly-free-dates for Michigan table at bottom of article). Generally speaking, the fly-free-date is during the first week of September in northern Lower Peninsula, around mid-September in mid-state areas, and the third or fourth week of September for southern Michigan. Highest yields are often attained when seeding approximately five to 15 days following this fly-free-date. This timely planting helps insure that seedlings have sufficient time to develop an extensive root system and initiate multiple tillers before winter. Where wheat is planted before or within a few days following the fly-free-date, growers should significantly lower seeding rates and decrease or eliminate the use of nitrogen fertilizer at planting.

Seeding depth

Attaining a consistent depth, and thus even emergence, is often more critical than fine-tuning actual seeding depth. Usually, a planting depth of 1 to 1.5 inches is sufficient. Shallower plantings may emerge more quickly, whereas more deeply placed seed has the advantage of additional protection against winter stresses. An adjustment should be made where a field is exceptionally dry. In this case, the seed should be placed as deep as necessary to find moisture.

Planting rate

Planting wheat with tractorMichigan State University Extension’s recommendation is to plant between 1.4 and 2.2 million seeds per acre. Seeding rates on the lower end of the range should be reserved for fields being planted within a couple weeks of the Hessian fly-free-date. Using high seeding rates are discouraged when planting relatively early, as it may give overly thick stands for winter dormancy and eventually lead to plant lodging. As the calendar advances, seeding rates should become progressively higher. If planting continues into the second half of October, the seeding rate should be increased to at least 1.8 million seeds per acre. The seeding rates should also be adjusted upward when seed is of questionable quality.

Table 1 identifies the pounds of seed a grower would need based on the number of seeds per pound and their target seeding rate. For example, if the seed bag specifies there are 14,000 seeds per pound and the target seeding rate is 1.8 million seeds per acre, 129 pounds of seed would be needed per acre. Table 2 is useful for assessing the number of seeds being dropped by each row unit (7.5-inch row spacing) and for evaluating actual emergence.

Fall fertilization

University bulletins usually recommend 10 to 30 pounds per acre of fertilizer nitrogen in the fall. However, some observers find that little or no nitrogen fertilizer is necessary where seedings are made on a timely basis on moderately textured soils.

Phosphorus rates should be determined using soil test results. (See MSU Extension bulletin E2904, “Nutrient Recommendations for Field Crops in Michigan,” for more information.) Generally, growers are discouraged from using any phosphorus fertilizer where soil test results indicate 50 ppm (100 pounds per acre) or more. Even where phosphorus soil tests levels are above 25 ppm, wheat is not likely to show a response, though a small amount would help maintain current soil test levels. Ontario researchers report they see a yield response to placing phosphorus in the row at planting. While Michigan has not demonstrated this response to placement, in-row placement is not discouraged as it may offer greater nutrient-use efficiency.

Potassium fertilizer is usually broadcast applied in the fall. The actual rates are dependent on soil test levels, soil cation exchange capacities and yield potentials. For soils testing medium for potassium (75 to 100 ppm), approximately 100 pounds per acre of potash may be sufficient.

Table 1. Relating seed size and seeding rates to the amount of seed required per acre

Seed size (seeds/ lb.)

Target seeding rates (millions of seeds per acre)

1.6

1.7

1.8

1.9

2.0

2.1

Amount of seed required (lbs./acre)

10,000

160

170

180

190

200

210

11,000

145

155

164

173

182

191

12,000

133

142

150

158

167

175

13,000

123

131

138

146

154

162

14,000

114

121

129

136

143

150

15,000

107

113

120

127

133

140

16,000

100

106

113

119

125

131

17,000

94

100

106

111

118

124

18,000

89

94

100

106

111

117

* Seeds per acre / seeds per lb. = lbs. of seed per acre

Table 2. Relating target seeding rate per acre to seed and seedling numbers (for 7.5-inch row spacing)

Target seeding rate (millions per acre)

Seeds per feet of row¹

Seedlings per feet of row²

1.4

20.1

18.5 (92%)

1.6

23.0

20.7 (90%)

1.8

25.8

22.7 (88%)

2.0

28.7

24.7 (86%)

2.2

31.6

26.5 (84%)

¹ Target seeding rate/ 43560 X 0 .625 = seeds per ft of row (7.5” spacing). Seeds per sq. ft. = target seeding rate/43,560.
² An estimated emergence rate is given in brackets as percent (the rate tends to decline as seed rates increase).

Hessian fly-free-dates for Michigan

County

Sept.

County

Sept.

County

Sept.

County

Sept.

Alcona

6

Eaton

16

Lapeer

15

Ogemaw

10

Allegan

20

Emmett

4

Leelanau

8

Osceola

10

Alpena

9

Genesee

17

Lenawee

25

Oscoda

7

Antrim

4

Gladwin

12

Livingston

16

Otsego

6

Arenac

13

Grand Traverse

8

Macomb

18

Ottawa

19

Barry

18

Gratiot

15

Manistee

13

Presque Isle

8

Bay

14

Hillsdale

19

Mason

13

Roscommon

7

Benzie

16

Huron

13

Mecosta

12

Saginaw

16

Berrien

23

Ingham

17

Midland

15

Sanilac

15

Branch

19

Ionia

16

Missaukee

9

St. Clair

16

Calhoun

19

Iosco

7

Monroe

21

St. Joseph

23

Cass

22

Isabella

11

Montcalm

15

Shiawassee

16

Charlevoix

3

Jackson

16

Montmorency

7

Tuscola

15

Cheboygan

4

Kalamazoo

20

Muskegon

18

Van Buren

22

Clare

12

Kalkaska

5

Newaygo

15

Washtenaw

18

Clinton

17

Kent

18

Oakland

16

Wayne

18

Crawford

6

Lake

13

Oceana

16

Wexford

9

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