Seeding for Target Plant Stands, not lbs/ac

Seed can be an expensive input, but a poor crop stand can be lost profit.  To maximize your seed, still get the stand needed to optimize yield, start calculating the real seeding rate needed for the plant stand desired and not gauging seeding rate by lbs/ac or bu/ac.

The following are the standard recommendations for FINAL plant stand, not what you are putting in the ground. Germination, TKW and mortality are very important to use in the equation to determine actual seeds/ac to plant.  For example, if you assume your germination is 96% and its only 85% and conditions turn cold and wet (increasing mortality), you may have a lot thinner stand than you anticipated (which could mean a harder time controlling weeds).

                    Grain Crops                               Oilseed Crops                   Pulse Crops        
Barley Wheat Oat Corn Canola Sunflower Flax Peas Soybean Dry Bean*
Plants/ft2 22-25 23-28 18-23 7-14 37-56 7-9
 Plants/ac (1000s) 26-30 18-22 180-210 85-100
Mortality Rates (%) 10-15 10-15 10-15 10-15 20-60 10 40-50 5-15 5-10 5-10

*Navy Bean = pinto beans on lower end and navy bean require higher plant stands

Source:  Manitoba Agriculture, Canola Council of Canada, Flax Council of Canada, Ontario Ministry of Agriculture, Food and Rural Affairs

 Seeding Rate (lbs/ac) = target plant stand/ft2 x TKW (g) / % expected seed survival x 10                       

 e.g. FLAX Seeding Rate= 45 plants/ft2 x  5g (TKW) / ((88% germination x (1- 40% mortality)) X 10 = 43 lbs/ac

Other information

Wheat – http://www.gov.mb.ca/agriculture/crops/production/print,aiming-for-higher-wheat-yields.html

Using 1000 Kernel Weight for Calculating Seeding Rates – http://www1.agric.gov.ab.ca/%24department/deptdocs.nsf/all/agdex81

Canola – http://www.canolacouncil.org/canola-encyclopedia/crop-establishment/seeding-rate/

Optimizing Plant Establishment – http://www.gov.mb.ca/agriculture/crops/production/pubs/optimizing-stand-establishment-in-less-than-optimal-conditions.pdf

 

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Book Enough Winter Wheat Seed to Hit Your Target Plant Stand!

It’s that time of year when producers are booking their winter wheat seed. To order enough seed, you’ll need to know how much is needed for the acres you have planned – and you can go one step further than using the ‘rule of thumb’ of 2 to 2.5 bushels per acre.  To calculate seeding rate and how much seed is needed, the following critical pieces of information are required.

Target Plant Stand. For winter wheat, producers should be aiming for a target plant stand of 30 plants per square foot in the fall. In the spring, it is hoped established plant stand will be 25 plants per square foot to maximize yield potential and increase crop competitiveness.

Thousand Kernel Weight (TKW). TKW is what it sounds like – the average weight in grams of a 1000 kernels. There is variability between winter wheat varieties commonly grown in Manitoba. If looking at registration data, varieties such as Emerson or CDC Falcon had TKWs around 29 to 30 grams, while varieties such as AAC Gateway had a TKW of 32 grams and AAC Elevate had a larger seed size of 36 grams per 1000 kernels. Remember TKW can change yearly based on growing conditions – just because your chosen winter wheat variety was 32 grams in 2015 does not mean that it will be the same in 2016.

Expected Seedling Survival Rate. Expected seedling survival rate is the percent germination less an amount for seedling mortality.

The percent germination will of course be available from your seed retailer if you are booking certified seed. If considering using farm-saved seed, also be sure to test – and make sure a test is done after seed cleaning and at an accredited lab (and no…..kernels on a wet paper towel on a windowsill is not a germination test!!). Since most germination tests are relatively inexpensive, it is a small price to pay. And while you are having percent germination done, get the TKW as well.

The other factor of expected seedling survival rate is seedling mortality, i.e. what percent of viable seed will germinate but not produce a plant. I wrote a Crop Chatter post on April 26th asking readers if they’d considered their seedling mortality. The focus was on spring cereals, but the same principles apply to winter wheat as well. Seedling mortality can vary greatly from year to year, and field to field. For spring cereals, seedling mortality rates can range from 5 to 20%.  However, for winter wheat a seedling mortality rate on the higher end of the range should be used to take into account winter survival.

The Western Winter Wheat Initiative (www.growwinterwheat.ca) suggests using an expected seedling survival rate of 70%, which takes into account germination, emergence rate and the impact of winter survival.

So obtaining the above information may not be as easy as using a bushel per acre seeding rate. However, taking those extra steps will help ensure you are hitting your target plant stand – one of the first steps in setting your 2017 winter wheat crop up for success.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

For more information on winter wheat production, visit Manitoba Agriculture’s website at http://www.gov.mb.ca/agriculture/crops/production/winter-wheat.html

 

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Doing Plant Counts in Your Cereals

Yield potential in cereals is a function of three components:  number of heads per unit area (plant population), kernel number per head and kernel weight.  A decrease or increase in any of these components can directly impact final yields.  So the seeding operation is the critical first step in maximizing yield potential as it is important that you begin with an optimal plant population.

After your cereal crops emerges, evaluating plant stands is an important step to take in order to gauge crop productivity.  It is always a good idea to go back to the field and do some plant stand counts to assess your seeding operation or even your planting equipment.

May 10, 2016_de Rocquigny, Pam

Taken May 10, 2016 (Photo by: P. de Rocquigny)

A quick and easy way to do plant stand counts to determine the length of row needed to equal one square foot (see table below). Then count the plants in that length of row.  Do this several times in a field and calculate an average plant stand per square foot.  Try to choose random areas of the field and try to avoid selecting the ‘best’ or ‘worst’ parts of the field.

Length of row needed for 1 square foot.
Row Width (in) Row Length for 1 sq ft
(ft) (in)
6 2.0 24.0
7 1.7 20.6
7.5 1.6 19.2
8 1.5 18.0
10 1.2 14.4

 

Or if you don’t have the table handy, divide 144 (the number of inches in a square row) by the row width in inches. The answer is the number of inches of each row you need to count plants in to equal a square foot. For example, for 8 inch rows, 144/8 = 18 inches (once again, see table above). If you count the number of plants in 18 inches of row, you then know the plant stand per square foot.

Good luck with your plant stand counts!

 

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TKW and Canola – How Much to Seed?

Canola seed weight (TKW) can vary widely by variety and in different seed lots.  Where small seed could be  3 g/1000 seeds and heavy, large seed at 7g/1000 seeds.  With not changing the intended lbs/ac seeding rate between the varieties or seed lots, the actual seeds put in the ground have been reduced, which affects final plant stand. Targeted final plant stand is recommended to be between 7 to 10 plants/ft2.  To find out the TKW, look on your bag of canola, it should be printed on it. 

To figure out how to use TKW and Targeted Plant Stand to determine seeding rate you can use this chart below, or use this formula:

FORMULA 1 :   9.6 x Target Plant Stand x TKW = Seeding Rate (lbs/acre)

From here, an adjustment needs to be made for seedling survivability.  In any given situation there will be some seeds that do not make plants.  In great growing conditions (soil above 5C, firm seedbed and adequate soil moisture), there will be probably 75% survivability, in cold soils either dry or wet, probably only 50%.  To adjust, divide the above formula by the expected survival rate:

FORMULA 2 :   9.6 x Target Plant Stand x TKW = Seeding Rate (lbs per acre)/ % Survivability

Example: I want 8 plants/ft2 final stand and my TKW is 4.0.  The soil has just only reached 5C, but it looks like cool, wet weather ahead, so I am guessing only 65% of the seeds will make plants

Seeding Rate = (9.6 x 8 x 4.0)/65 = 4.72 lb/ac

 

Seeding rate canola TKW

If you have questions, give me a call: Anastasia Kubinec, 204-750-2717

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