NDSU Crop and Pest Report

Plant Science


ISSUE 9  June 26, 2003

SOYBEAN: STAND COMPENSATION AND YIELDS

Soybean have the remarkable ability to compensate for reduced stands through aggressive branching. University of Minnesota research suggests that even substantial reductions in plant stands has negligible impact on yield. The data below from the National Hail Insurance Services handbook supports this research.

Soybean Stand Reduction Loss

- ROW WIDTH -

Plant/A
1000's

Yield %
Optimum

30"

15"

7.5"

103

52

26

180,000

100

92

46

23

160,000

100

80

40

20

140,000

100

69

34

17

120,000

99

63

32

16

110,000

97

57

29

14

100,000

94

52

26

13

90,000

90

46

23

11

80,000

86

40

20

10

70,000

82

NOTE: All plant counts are made on the basis of "number of plants in 10 feet of row."

As the above table indicates, reduced soybean stands can produce acceptable yields. However, weed control management may need to be closely watched. Incomplete canopy closure can create additional weed pressures.

 

HAIL DAMAGE IN ROW AND OILSEED CROPS

Hail damage to crops occurs somewhere in the state every year. Reports have already been made of hail in some areas of the state. When hail damage occurs on corn, soybean, dry bean and sunflower early in the growing season, replanting is possible; but deciding whether to replant is usually difficult. However, in late June its too late to replant any of the above mentioned crops. Total stand reduction, leaf loss, stem injury, weed control, and calendar date are factors to consider when making this decision.

Corn: The growing point remains below ground 3 weeks or more after the plant emerges (V5). If the growing point is not damaged, corn will recover and perform better than replanted corn. Split the stalk down the center and inspect the growing point. If normal, it will appear white in color and firm in texture. Injured growing points will appear brown or discolored 2-3 days following the hail. Complete loss of leaves early to corn when small usually does not greatly affect grain or silage yields. Corn in the silking and tasseling stage when damaged by hail can result in severe yield losses.

Soybean & Dry Bean: The growing points of beans is located in the top of the plant and in leaf axis. Growing points of beans are easily damaged by hail soon after emergence. Regrowth will not occur if hail stones cut the stem off below the cotyledonary node. If the top of the plant is damaged, regrowth can occur from one or more axillary buds. Bean stems may be bruised or broken. The damage may not be severe enough to kill the plant. However, the plant may lodge later as the callus tissue is weak and cannot support the pod weight. Reduction in stands to four plants per linear foot of row can still produce fair yields in soybeans planted in 30 inch row spacings.

Sunflower: Sunflower may be more tolerant than beans, but the degree of hail tolerance depends on the intensity of the hailstorm and the stage of growth. Sunflower is least tolerant during the seedling and budding stages, and most tolerant after flowering. Hail damage may be direct or indirect. Direct damage results from stand reduction, loss of recoverable heads because of severely bruised or broken stems, and head shatter at later stages. Indirect damage results from defoliation and disease infestation to injured plant tissue.

Research conducted on simulated hail losses in sunflower indicated that a one-to-one relationship does not exist between stand reduction and yield loss. A 50% stand reduction resulted in only 28% yield reduction. Defoliation of sunflower by hail was reported to be most damaging during the bud stage. Defoliation of 80% at the bud stage resulted in yield reduction of 53%. Whereas 80% defoliation at the 50% mature stage resulted in only a 12% yield loss.

Mustard and Canola: Plantings in seedling stages can have stands reduced to 1/3 of normal and produce acceptable yields. Plants hailed prior to flowering suffer yield loss because of loss on leaf area (the crop will still produce 60-80% of normal yield if enough material is available for regrowth). Seed yield losses in Canola is 25% of percent of leaf area lost. Plants injured in early flowering seldom die; however, yield loss can be severe. Canola that is similar to yellow mustard in maturity suffers increasing yield loss as flowering progresses. Plants that have been flowering 7 to 14 days will have yield losses due to hail equal to percent of branches lost. If 70% of branches are lost, 60-70% of yield will also be lost.

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

 

WHITE WHEAT VARIETIES FOR NORTH DAKOTA

There has been a great deal of interest in hard white wheat (HWW) this year due to the incentives for its production in the new farm bill. These incentives consist of a payment of $2 an acre for planting HWW and 20 cents for each bushel sold as HWW. The US Government is providing these incentives in order to increase the production of HWW that potentially could be exported for use in the large and expanding noodle market in Asia. Currently wheat from Australia dominates that market. Last year less than 1% of the wheat area in ND was planted to white wheat varieties. Once the wheat variety use survey results are released next month, it will be interesting to see the impact of this program on white wheat plantings this year. For those interested you can find more background information on white wheat from the web site developed by Dr. Berzonsky, the white wheat breeder at NDSU (http://www.ndsu.nodak.edu/instruct/berzonsk/breeding/White%20Wheat.html).

If you are considering growing white wheat, now is the time to take a look at the available varieties in the field. If no one in your community is growing a white wheat variety, you can find them in research plots at any of the Research and Extension centers. I also included the three hard white wheat varieties I describe below in county variety trials in the eastern part of the state and would be happy to direct you to those plots if you are interested.

There are a number of hard white spring wheat varieties that have been developed by breeding programs in the USA and Canada. Based on data from trials conducted in ND and Montana the following three were the best for yield and general adaptation. I would suggest you take a look at these varieties this summer if you get a chance.

Argent

Argent was released by NDSU in 1998. Argent has excellent baking quality and is genetically similar to Grandin. It is susceptible to leaf rust and scab, is relatively early maturing, average yielding and has good straw strength. Although Argent meets the color standards of a white wheat, its kernel color is not as white as desired by some millers and end-users. The quality of Argent makes it primarily suitable for bread-making ; it is not suitable for the noodle market because of its starch and noodle color characteristics.

AC Vista

AC Vista was develop in Canada and has very good yield potential in North Dakota (similar to or better than Parshall in two years of testing at seven locations in ND and MT). This variety is also more suited to a bread-making market since it also does not exhibit desirable noodle color characteristics.

Lolo

Lolo was developed by the University of Idaho. It is usually not as high yielding as Argent and AC Vista, but its starch and noodle color characteristics make it suitable for the Asian noodle market.

Special Management Practices for Hard White Wheat Varieties

For white wheat intended for bread making (i.e. Argent), high protein is required so N management should be similar to that used for HRSW varieties. Lower protein (10-12%) is required in varieties grown for the noodle market, so late-in-the-season applications of N should be avoided. All HWW varieties adapted to ND are susceptible to scab, so if grown in a scab prone area of the state, they should be sprayed with an approved fungicide. Leaf rust is likely to be a problem with most HWW varieties. They are also more prone to sprouting than HRSW varieties, so they should be harvested in a timely manner in order to avoid sprouting. Preliminary evidence suggests that growing white wheat varieties under irrigation will elevate grain ash content, which could be an undesirable result if it is intended for a noodle end-use market as higher ash tends to discolor noodles.

Marketing Hard White Wheat

The white wheat market is fairly specialized as certain varieties are better suited for specific end uses. My recommendation is that you secure a buyer before you grow white wheat. Most white wheat contracts will be variety specific and will therefore dictate the variety or varieties that you can grow.

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


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