Seeding Rate Calculator

General recommended seeding rates for soybeans in Manitoba are 190-200,000 seeds/ac for air seeders (based on 70-75% expected seed survival) and 170-180,000 seeds/ac for planters (based on 80-85% expected seed survival). The aim is to establish a live plant stand of 140-160,000 plants/ac. This recommendation can be fine-tuned for individual operations by using this calculator.

Step 1

Identify the economically optimum target plant stand based on the following economics:

Fill In The Following:

Update The Table Below

Step 2

Tap the target plant stand (plants/ac) that provides the highest relative return

Plant Stand
Yield Potential
Relative Return
(Tap to use in Step 3) (% of Optimum) ($/ac)
60,000 - -
80,000 - -
100,000 - -
120,000 - -
130,000 - -
140,000 - -
150,000 - -
160,000 - -
180,000 - -

Step 3

Determine your seeding rate based on expected seed survival.

Fill In The Following:

On-Farm trials in Manitoba have shown an average seed survival of 74% for air seeders on 15 farms (range 45-90%) and 82% for planters on 11 farms (range 60-96%).

Calculate


Suggested Seeding Rate:
- seeds/ac or - units/ac

To convert the seeding rate to lbs/ac, take 'Seeds/ac' and divide by 'No. of seeds/lb', which can be found on your seed tag label.

Expected Seed Survival

Expected seed survival (or % emergence) is calculated as:

This value is farm and field specific and is influenced by:

Relative Return


The relative return is calculated based on yield potential, relative seed cost and relative income for each plant stand. Relative seed cost and income are compared to the standard practice of establishing a plant stand of 160,000 plants/ac. This plant stand has been found to produce the highest yield and levels above this do not result in increased yield.

Yield Potential


Based on a yield response curve developed from research conducted at 13 site-years across Manitoba from 2011-2013 by Dr. Ramona Mohr at Brandon Research Centre (Agriculture and Agri-Food Canada). Funding provided by Manitoba Pulse & Soybean Growers.

Includes cost of seed, inoculant and seed treatment if applicable. A unit is a bag of 140,000 seeds.