Seeding Rates for Cereals
Author: Peter Boswall,Field Crop Specialist, Farm Extension Services, Department of Agriculture, Fisheries, and Aquaculture
Seeding rates for cereals are still commonly given in figures of kilograms of seed per hectare or pounds per acre. Such rates are both convenient and useful to indicate the approximate quantity of seed that is required. However, simply using a standardized rate per hectare or acre may not provide a sufficient plant population to achieve optimum use of nutrients or the sun’s energy to produce yield.
Research conducted in both Prince Edward Island and elsewhere in the region has demonstrated that barley production requires a plant stand of 325 to 375 plants per square metre for 6-row barley and 350 to 400 plants per square metre for 2-row barley. Target populations could be even higher, 450 plants per square metre, for an intensively managed milling wheat variety.
Along with the target plant population two other factors should be considered when planning your cereal seeding, they are the seed germination and the thousand kernel weight (TKW). Both seed germination and thousand kernel weight tests can be obtained through the Department of Agriculture and Forestry’s Soil and Feed Testing Lab in Charlottetown. The Lab report using the TKW and germination percent, will provide seed rates in both Kg/Ha and Lbs/A.
Table 1: Effect on plant population per square metre using constant seed rate per hectare (125 kg/ha) at two different TKWs assuming 90% seed germination and emergence.
|Expected Plant Populations|
|TKW||Estimated plant population||Optimum plant population||% of optimum population|
The calculation to determine the quantity of seed required to optimize the plant populations as follows:
- Know your target population goal in this case 350 plants per square metre,
- Have the results of a germination test which provides an indication of expected plant establishment in the field,
- Finally have the Thousand Kernel Weight (TKW) for the seed to be planted.
Once this information is at hand it can be used to determine the planting rate by using the following formula:
|Seed rate1||=||Target population (plants per m2) x TKW (g)|
|(kg/ha)||Expected % germination|
As an example a 2-row barley has a TKW of 51g and a germination test result of 95% then the seed rate should be:
|Seed rate||=||350 plants per m2 x 51g||=||188 kg/ha|
1 Kilograms of seed per hectare can be converted to pounds per acre by dividing kg/ha by 1.12