Planting the 2015 winter wheat crop

Much of winter wheat’s yield performance is determined by the decisions of growers at the time of planting.

The initial goal of planting winter wheat should be to seed on a timely basis and in a way that leads to even and uniform stand of seedlings. When this is achieved, top grain yields can often be realized.

Field preparations

The chance of achieving a consistent stand is greatly improved by insuring residue from the previous crop is spread uniformly. Particularly for no-till operations, bunched-up residue is the most common threat to consistency in wheat stands. In some cases, the coulters are unable to cut through the thick residue or the emerging wheat simply rots below the layers of plant material. Adding weight to the drill may help in penetrating crop residue (or hard soil). In some cases, the only alternative is to use tillage to help disburse and bury the residue. Tillage or a nonselective should be used to insure a weed-free start to the crop.

Planting date

While the Hessian fly no longer poses a significant threat to wheat in Michigan, the Hessian fly-free-date is still a useful reference relative to projecting wheat’s performance and disease development (see table at the end of this article for county fly-free dates). Although the best date to plant wheat varies from year to year, the date is likely to fall within the first two weeks following the area’s fly-free-date. This timing helps insure that seedlings have sufficient time to develop a strong root system and initiate multiple tillers before winter dormancy.

Where planting is delayed a few weeks beyond the fly-free- date, the crop’s yield potential tends to decline at least one bushel for each additional day of delay. When wheat is planted before or within a few days following of the fly-free date, growers should consider lowering their seeding rate; decreasing or eliminating nitrogen fertilizer at planting-time; and monitor the seedlings for aphids.

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 as was seen this past year. 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

Michigan 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 fly-free-date. Higher rates at this time are discouraged as overly thick stands may encourage lodging. As the planting season goes on, the seeding rates should become progressively higher. If planting continues into the second half of October, the seed rate should be increased to at least 2.2 million per acre. The seeding rates should also be adjusted upward when seed is of questionable quality.

Table 1 identifies the pounds of seed that a grower would need based on the seed count per pound and his target seeding rate. For example, if the seed bag specifies that 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

Generally, the current recommendation is for wheat to receive between 10 and 25 pounds of fertilizer nitrogen at planting. However, growers often find they need little or any extra nitrogen at planting especially where the seeding is made relatively early in the fall and where there is plenty of soil nitrogen left by the previous crop. All phosphorus and potash should be applied in the fall, with rates determined by soil test levels. In general, soils having medium test levels of phosphorus (25-40 ppm) require approximately 50 pounds per acre of phosphate. For silt loam soils testing medium for potassium (75-100 ppm), approximately 60 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 row 2

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%)

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

Related Events

Related Articles

Related Resources