How to Increase Oat Grain Numbers

Grain number is a function of the number of fertile shoots per unit area and the number of grains per head.

The main impact of nutrition is on this is on the numbers of grains per head.

Crop Nutrition and Oat Grain Numbers per Ear in Oats


Nitrogen will affect the number of grains that are set on individual ears. A high yielding crop of oats will have approximately 30-40 grains / ear, however if nitrogen supply is limiting this will be reduced.

Effect of nitrogen timing on grains  ear of spring oats

The timing of the applied nitrogen is important as grain numbers are determined early from double ridge to floret initiation.

Early applications of nitrogen increases the number of grains / ear.


Manganese, zinc, copper and boron are the essential micro nutrients that affect the number of grains/ear and hence increase grain yield. Copper affects the quality of pollen and therefore the number of grain sites that set seed. Blind sites are associated with copper deficiency.

Other crop management practices influencing oat grain numbers

The number of eventual grains per ear varies from season to season and is affected by a number of factors including:

  • Varietal choice 
  • Disease control during flowering 
  • Weather conditions during flowering 
  • Temperature and day length before terminal spikelet (Zadoks GS 30)