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Grain Corn Agronomy

Farming Smarter Project

Timeline: 2015 – 2017

Project contact: Ken Coles



To take advantage of a huge production and profit opportunity for Alberta farmers, Farming Smarter looked for the best ways to grow grain corn in Alberta’s climate and soils. There are new short season, early maturing grain corn varieties for Alberta and Saskatchewan.

Corn seedling

This 3-year study conducted trials under two field moisture conditions dryland (DL) & irrigated (I). Each trial examined a different aspect of grain corn agronomics including optimum plant population, fertilizer types/rates and crop rotations. We used new grain corn hybrids with Corn Heat Units (CHU) ranging from 2000 -2150. These hybrids were selected from a number of seed brands participating in the hybrid corn performance varietal trials conducted by the Alberta Corn Committee.


  1. Determine optimum previous crop residue and seeding systems (conventional vs zero-till) for grain corn production under rain fed conditions in southern Alberta.
  2. Determine optimum row spacing and plant populations for grain corn production under rain fed conditions in southern Alberta.
  3. Determine optimum nitrogen response for grain corn production under rain fed conditions in southern Alberta.
  4. Evaluate available low heat unit corn varieties under rain fed conditions in southern Alberta.


Farming Smarter staff harvest corn in the corn agronomy trial plots in fall 2016.

The study design aimed to find the ideal plant population, row spacing, fertility, crop sequence and tillage requirements for growing dryland grain corn in southern Alberta.

Collaborators: AAFC – Brian Beres, Manjula Bandara

Study 1. Plant Population and Row Spacing

Factor 1: Row spacing (inch) – 2 (20”, 30”)
Factor 2: Plant population – 5 (15000, 20000, 25000, 30000, 35000 seeds/ac)
Factor 3: Locations – 3 (Lethbridge, Bow Island, and Medicine Hat from 2015 until 2017)

Study 2. Nitrogen Fertility Requirements

Factor 1: Fertilizer – 8 (5 N rates: 0lbs, 50lbs, 101lbs, 160lbs, 191lbs, 50 lbs side banded + 50 lbs in crop, 50 lbs
side banded + 100 lbs in crop, 100 lbs side banded +100 lbs in crop).
Factor 2: Locations – 4 (Lethbridge, Bow Island, and Medicine Hat from 2016 until 2017)

Study 3. Tillage system and crop rotation impacts to corn production

Factor 1: Previous crop – 7 (wheat, soybean, peas, lentils, mustard, canola, corn)
Factor 2: Tillage – 2 (Zero till, and Conventional Till)
Factor 3: Locations – 3 (Lethbridge, Vauxhall and Medicine Hat from 2016- 2017)

Study 4. Variety maturity rating performance

Factor 1: Varieties (number of varieties varied from year to year).
Factor 2: Location –2 (Lethbridge and Medicine Hat for 2016 and 2017, Lethbridge only in 2015)

Data collected in all trials included plant counts, corn stand density, plant height, days to tasseling, silking, & maturity, lodging ratings, corn yield, and corn test weight.


Study 1: Plant Population and Row Spacing

The population and spacing study showed that narrow rows (20”) and high seeding rates (35,000 seeds/ac) produced maximum corn yields.  Corn yields were 9% higher when seeded on 20” spacing vs 30” spacing.  Generally, yield increases linearly with increasing plant population (Appendix 3, Table 1). Days to tassel, silk and maturity were one day longer from highest to lowest seeding rates (35,000 seeds/ac vs 15,000 seeds/ac), but did not noticeably effect maturity.

Study 2: Nitrogen Fertility Requirements

Nitrogen fertilizer had little effect on corn yield. Comparing total available nitrogen (soil available + fertilizer) versus corn yield showed very little response between 50lbs/ac and 200 lbs/ac. Below 50 lbs/ac and above 200 lbs/ac, there was a small yield decrease. Higher nitrogen rates also increased days to tassel, silk and maturity by approximately one day (Appendix 3, Table 2). 

Study 3. Tillage system and crop rotation impacts to corn production 

Corn sequencing test plots at Farming Smarter.

This study did not show a significant yield difference between pre-plant tillage and direct seeding.  However, corn emergence in the conventional system was 99% and only 84% in the no-till plots. This is caused by hair-pinning and issues with residue from the previous crop. Better residue management at harvest; properly adjusted residue managers during planting and following a low residue crop could address these issues. For instance, grain corn yielded highest following pulse crops (as well as corn), when direct seeded. Further research may facilitate adapting planters to zero-tillage and prove the value of rain-fed corn production in southern Alberta.  

Study 4: Variety maturity rating performance

Studies 1-3 used the variety with lowest available heat unit rating. This study sought to roughly evaluate varieties from various companies with various maturity ratings. There was a 250 kg/ha increase in average yield by going from a 2000 CHU variety to a 2500 CHU variety (appendix 3, figure 13).  However, yields of different varieties at each CHU could vary as much as 1000 kg/ha (appendix 3, tables 5-9), making comparisons at various heat units difficult. Days to tassel, silk and maturity were all lengthened with increased CHU rating (figure 14), but not enough to cause problems for harvest.  The date of the first frost (-2°C) ranged from September 17 to October 24 (table 10) usually leaving adequate time for maturity.  Industry experts warn that most seed companies use differing methods in assigning CHU ratings; which this data set makes apparent.   The intent of this study was not to aid in variety selection, but to determine if there is opportunity for higher yields.


Despite less than ideal growing conditions during this study, grain corn still produced yields that can benefit producers under irregular southern Alberta dryland conditions. We recommend that producers seed dryland grain corn on narrower rows (20”) at higher seeding rates (30,000 +seeds/ac) targeting between 50-200 lbs/ac available nitrogen for grain corn production. If using zero till, we recommend that producers manage crop residue by either raking away excess, sequencing after a low residue crops like lentils or use floating residue managers at seeding. Producers should choose a variety of grain corn based on local area average CHU to maximize yield potential. Further research might evaluate proper residue management to optimize the yield potential of zero till grain corn. Also, it could evaluate if nitrogen is more essential in the growth of grain corn under irrigated conditions.

Final Report

Read the complete project report

Final Grain Corn Report


Corn adoption on the Prairies set to speed up
Country Guide Feb. 2018

Higher seeding rate helps grain corn
The Western Producer Jan. 2018

Grain Corn Offers Opportunity
Farming Smarter Magazine, Fall 2017, page 27

Dry Soil Hampers Corn
Farming Smarter Magazine, Fall 2017, page 24

Learning in the field at Farming Smarter
Farming Smarter Magazine, Spring 2017, page 11

Corn plots at Lethbridge

Dryland grain corn can fit prairie rotations
Farming Smarter Magazine, Spring 2017, page 24 

Higher Seeding Rate Helps Grain Corn
The Western Producer—2017

Farming Smarter brings Innovation Together
Medicine Hat News—July 7, 2017

Grain corn project surprises researchers
Farming Smarter Magazine, Spring 2016, page 26

Alberta Crop Industry Development Fund (ACIDF), 
Farming Smarter Magazine, Fall 2015, pg 12

Corn on Deck for Rotations
Farming Smarter Magazine, Spring 2015, pg 8- 9

Farming Smarter
Cypress County impress in Medicine Hat – July 14

More Corn Acres Could Hike Fusarium
The Western Producer Aug. 2015

Cows on Corn Need Attention
The Western Producer Jan. 2015




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