ISSUE 15    August 17, 2006

PLANTING WINTER WHEAT IN 2006

In many areas of the state, winter wheat yields were very good in 2006 even though limited rainfall and high temperatures characterized the growing season. Winter injury was not a significant constraint in much of the state as winter temperatures were relatively mild. A few areas (i.e. Hettinger REC), however, reported winter kill as there was virtually no snow cover the whole winter, did experience a significant stand loss during the winter. Winter wheat can be a profitable crop as it has high yield potential, requires less inputs than spring planted cereals, and is planted and harvested at off-peak periods for labor and equipment use. Nevertheless, winter wheat must be properly managed in order to reduce the risk associated with winter injury. Key recommendations for growing winter wheat in ND include the following:

Planting date: The optimum planting date for the northern half of the state is September 1-15 and for the southern half September 15-30.

Planting depth: Adequate moisture for establishing winter wheat is often a concern as the soil profile is usually depleted of moisture in the fall. If there is little or no moisture in the soils surface, planting shallow (1 to 1.5 inches deep) and waiting for rain is recommended.

Seeding rates: Generally a seeding rate of 900,000 to 1 million viable seed per acre is adequate. Higher seeding rates may be appropriate if planting late or when planting into poor seedbeds.

Plant in to crop residue: The best winter survival is achieved when winter wheat is no-till planted into standing crop residues that are able to catch and retain snow. Planting winter wheat into a low residue crop such as soybean increases the risk of winter kill, so only the most winter hardy varieties should be grown (see data on winter survival in 2005/06 in the following table and at http://www.ag.ndsu.nodak.edu/aginfo/smgrains/WWsurvial.htm).

Variety selection: In addition to agronomic characteristics such as plant height, yield, and disease and lodging resistance, also carefully consider the winter hardiness of a variety. In many years there is a direct correlation between winter survival and yield. The following table summaries the yield of winter wheat from four locations in ND in 2006. In eastern locations yields were exceptionally high due to the absence of disease and the excellent winter survival of the crop. The low yields recorded at Hettinger were mainly due to poor winter survival associated with limited snow cover during the winter. In addition to the data below, review the results of previous years and locations (see http://www.ag.ndsu.nodak.edu/aginfo/variety/a1196.pdf).

Joel Ransom
Extension Agronomist - Cereal Crops
joel.ransom@ndsu.edu

 

Table 1. Yield and winter survival of winter wheat varieties grown in 4 locations in 2006.

Variety

Lisbon

Prosper

Hettinger

Mandan

Avg. of locations

Winter survival1

 

---------------------bu/acre-------------------

(%)

CDC Buteo
Wesley
Harding
Radiant
Expedition
Jerry
Yellowstone
Goodstreak
Millennium
Ransom
Wendy
Jagalene
Paul
Roughrider
CDC Falcon
McClintock

89.0
89.8
84.1
85.5
82.2
85.2
74.1
82.4
85.8
79.4
70.5
75.4
86.4
72.2
76.2
81.7

112.4
112.0
113.1
94.7
116.6
105.9
111.9
110.1
112.6
100.9
112.4
102.4
89.3
87.8
101.2
97.1

36.9
19.1
27.0
4.7
19.4
24.8
27.0
17.8
8.7
30.4
18.9
20.9
22.4
28.3
8.7
8.9

38.3
41.1
36.5
36.5
36.9
39.1
34.5
34.5
36.9
30.9
39.5
42.0
41.5
37.2
37.4
35.7

69.2
65.5
65.2
64.6
63.8
63.7
61.9
61.2
61.0
60.4
60.3
60.2
59.9
56.4
55.9
55.9

87
64
68
88
71
77
42
44
48
73
61
56
63
73
46
40

Average

81.2

105.0

22.6

37.4

61.6

62

1-Average of Hettinger and Mandan locations. There was no significant winter injury at Lisbon and Prosper in 2006.

 

FLAX HARVESTING AND MATURITY

Flax is starting to turn in many areas of the state and the grasshoppers will be soon attacking this vulnerable crop. It should be harvested as soon as its ready to reduce crop loss and boll drop. Maturity in flax is judged by color of the bolls rather than by color of the straw. Flax may continue to bloom until frost if sown late or if the season is wet and cool. Flax is most susceptible to cold damage during flowering and early boll stages. The immature seeds, which may contain as much as 75 percent moisture, will likely be killed by freezing temperatures that do not completely kill leaves and stems. The degree of injury from freezing is dependent on the minimum temperature, condition of the plant, the soil moisture and weather conditions both before and after freezing.

Seeds from these late flowers seldom mature and are lost during threshing and cleaning. Flax is ripe enough to combine when about 90 percent of the bolls have turned brown. Any delay after this stage increases the chance of storm damage and allows weeds to grow and become more troublesome. If a swather and pickup combine are used, harvesting a few days earlier than when 90 percent of bolls are brown does not affect yield or quality.

Flax may be harvested with a swather or by direct combining. Direct combining is the cheaper method and is entirely satisfactory when the flax is thoroughly dry and free of weeds. The use of harvest desiccants can help the direct harvesting practice. However, still the most common method of harvest in many growing areas is with the swather plus combine with a pickup attachment because few fields are free of weeds and few ripen uniformly. Swathed flax usually is in condition to combine after a few days of dry, sunny weather. Swath rollers are often used to pack the windrow to prevent destruction and movement by wind.

 

ROW CROPS AND ESTIMATION OF YIELD POTENTIAL

Corn Yields

There are several techniques for estimating corn grain yield prior to harvest. This version was developed by the Ag. Engineering Department at the University of Illinois and is the one most commonly used. A numerical constant for kernel weight is figured into the equation in order to calculate grain yield. Since weight per kernel will vary depending on hybrid and environment, the yield equation should only be used to estimate relative grain yield. For example, yield will be overestimated in a drought year such as 2006 with poor grain fill conditions, while it will be underestimated in a year with good grain fill conditions.

Step 1. Count the number of harvestable ears per 1/1000th acre. (Table 1)

Step 2. Count the number of kernel rows per ear on every fifth ear. Calculate the average.

Step 3. Count the number of kernels per row on each of the same ears, but do not count kernels on either the butt or tip that are less than half size. Calculate the average.

Step 4. Yield (bushels per acre) equals:

(ear #) X (avg. row #) X (kernel #)

90

Soybean Yields

Soybean yield estimates are most accurate within three weeks of maturity, but are still only estimates. Assume 2.3 bean per pod.

1. Determine the number of feet of row needed to make 1/1000 of an acre (Table 1).

2. Count the number of plants in ten (10) different randomly selected sample areas. Calculate the average.

Avg. = _______________________ = A (plants/A)

3. Count the number of pods per plant on ten (10) randomly selected sample areas. Calculate the average.

Avg. = _______________________ = B (pods/plant)

4. Calculate pods/acre by multiplying plant population by pods/plant.

A X B = _____________________ = C (pods/acre)

5. Calculate seeds/acre by multiplying pods per acre by an estimate of 2.3 seeds/pod.

2.3 X C = ____________________ = D (seeds/A)

6. Calculate pounds/acre by dividing seeds/acre by an estimate of 3000 seeds/pound.

D ÷ 3,000 = __________________ = E (lbs/A)

7. Estimate yield by dividing pounds/acre by 60 pounds/bu.

E ÷ 60 = _________________ = Yield (bu/A)

Table 1. Length of row equal to 1/1000th acre. An accurate estimate of plant population per acre can be obtained by counting the number of plants in a length of row equal to 1/1000 of an acre. Make at least three counts in separate sections of the field, calculate the average of these samples, then multiply this number by one thousand (1,000).

Row Width

Length of Single Row to Equal 1/1000 of an acre

(inches)

(feet)

(inches)

6
7
8
10
15
20
28
30
32
36

87
74
65
52
34
26
18
17
16
14

1
8
4
3
10
2
8
5
4
6

Dry Edible Bean Yields

You can estimate dry bean yields by knowing the number of seeds per pod, pods per plant and plants per 1/1000th of an acre. At the same time of counting seeds and pods, the maturity status of each should be determined.

If a seed or pod will not mature, it shouldn’t be counted. Then count the total plants per 1/1000th acre to complete the data collection.

Yield Estimation

Within a representative and uniform plant stand, randomly select five plants each from at least five randomly selected locations in the field.

Keeping all plant data separate, pull and count the pods from each plant and then count the seeds to determine average seeds per pod for all five replications. These data are combined with the average number of plants per 1/1000th acre

Average number of seeds per pound

Kidneys
Pintos
Great Northerns
Pinks/Small
Reds
Navies/Blacks

900-1000
1400
1600-1800
1600-2000
3000

Seeds per pound can vary 10-20% for different varieties within a bean class. If available, use reported estimates for seed number per pound for your variety.

The accuracy of yield estimate can be improved by counting seeds and pods from at least 10 plants per replication.

Calculations

1. (Average seeds per pod) X (average pods per plant) equals average seeds per plant.

2. Average seeds per plant) X (plants per 1/1000th of an acre) X (1000) divided by seeds per pound of the variety equals yield in pounds per acre.

Duane R. Berglund
NDSU Extension Agronomist
duane.berglund@ndsu.edu


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