Author: Greg Stewart

Greg Stewart

Former OMAFRA Corn Lead

Verifying a Pre-Sidedress Soil Nitrate Threshold Test for Evaluating Nitrogen Top-Up Needs

Greg StewartGreg Stewart February 4, 2015 2314 Comments Off on Verifying a Pre-Sidedress Soil Nitrate Threshold Test for Evaluating Nitrogen Top-Up Needs
Corn

Purpose: Pre-sidedress soil nitrate test (PSNT) provide a means of estimating soil nitrogen supply, and can aid producers in fine-tuning their nitrogen application rates for corn. One drawback of current soil nitrate tests is that they are only calibrated for situations where all of the nitrogen being measured has come from soil mineralization, that is cores need to be taken…

Investigating Yield and Economic Performance of a “Build and Maintain” Fertility Approach versus a “Sufficiency” Approach in Corn: Interim Report

Greg StewartGreg Stewart January 30, 2015 2346 Comments Off on Investigating Yield and Economic Performance of a “Build and Maintain” Fertility Approach versus a “Sufficiency” Approach in Corn: Interim Report
Corn

Current P and K recommendations in Ontario guide crop producers to apply a rate of fertilizer that will provide the greatest potential of an economic response during the year of application. Increases in crop yields over time have resulted in higher nutrient removal rates which have decreased the “equilibrium” soil test values where average crop removal rates equal the recommended…

2013 Grain Corn Ear Mould and Vomitoxin Survey

Greg StewartGreg Stewart October 15, 2013 2376 Comments Off on 2013 Grain Corn Ear Mould and Vomitoxin Survey
Corn

Co-Authored by: Albert Tenuta, OMAF & MRA Field Crop Pathologist The OMAF and MRA Field Crops team has recently completed a survey of the 2013 Ontario corn crop to determine ear mould incidence as well as the occurrence of mycotoxins in the grain.  These mycotoxins, particularly vomitoxin (DON) produced primarily by Gibberella/Fusarium ear moulds can be disruptive when fed to…

Corn and Cold September Nights

Greg StewartGreg Stewart September 17, 2013 2814 1 Comment
Corn

Cold September nights can cause widespread anxiety in corn producers.  The level of anxiety for most growers will be determined by the stage of maturity their grain corn crop has reached. As temperatures drop to zero frost damage first occurs to the leaves of the corn plants.  This damage will eliminate any further photosynthesis, reduce grain filling and often have…

Nitrogen Status in 2013 Corn Fields

Table 1-24 Pub 811
Greg StewartGreg Stewart June 11, 2013 2081 Comments Off on Nitrogen Status in 2013 Corn Fields
Corn

Co-Authored by Ian McDonald Background: In 2013 a range of corn fields were sampled to determine what impact the weather has had on the level of residual soil nitrate.  This year April was cool and relatively wet while the first half of May came in warm and dry followed by conditions since mid-May that have been cooler and wetter than average….

2012 Grain Corn Ear Mould and Vomitoxin Survey

Greg StewartGreg Stewart October 4, 2012 2431 1 Comment
Corn

Co-Author: Albert Tenuta, OMAFRA Field Crop Pathologist The annual corn ear mould and vomitoxin survey by the OMAFRA Field Crops team indicates that the 2012 Ontario corn crop is distinctly low in ear moulds and vomitoxin. However, stakeholders are reminded that individual field conditions (environmental, hybrid, tillage, rotation, etc.) are important in ear mould and mycotoxin development.  Growers should scout…

Corn Report – May 30, 2012

Greg StewartGreg Stewart June 1, 2012 1248 Comments Off on Corn Report – May 30, 2012
Crop Reports

Corn development has been rapid this past week.  Some areas were close to accumulating 200 CHU in 7 days!  Good soil conditions and early planting are paying off as the corn continues to move ahead despite relatively dry conditions.  Some replanting has occurred where low population and uneven stands were caused by cold shock to the seed or seedling.  Yield…

Ontario Corn Replant Decision Aid

Greg StewartGreg Stewart May 23, 2012 2128 Comments Off on Ontario Corn Replant Decision Aid

If you are unhappy with your stand of corn and think you may wish to replant, download the Ontario Corn Replant Calculator to assist you in this important decision. Many thanks to Dr. Dave Hooker and Ken Janovicek (Plant Agriculture Department, University of Guelph) for their efforts in putting this tool together. DOWNLOAD: THE ONTARIO CORN REPLANT DECISION AID, VERSION…

Corn Report – May 23, 2012

Greg StewartGreg Stewart May 23, 2012 1141 Comments Off on Corn Report – May 23, 2012
Crop Reports

Corn planting is essentially complete across Ontario other then a small amount of replanting due to emergence/stand issues or where corn is following first cut alfalfa. Use the Replant Decision Aid posted at www.gocorn.net if considering this where stands are thin. Start with accurate plant counts of the current stand and consider all the replanting economics (crop insurance, seed costs, herbicide and…

Corn Report: May 16, 2012

Greg StewartGreg Stewart May 16, 2012 1320 Comments Off on Corn Report: May 16, 2012
Crop Reports

Corn planting is 95 % complete across the province. Emergence is good to excellent in most areas with the majority of the corn in the 1-3 leaf stage. Weed control should be the priority as the crop approaches the critical 3-4 leaf stage. Cutworm injury has been reported in some areas south of London. Scout fields that had significant weed growth…

Corn Report: May 9, 2012

Greg StewartGreg Stewart May 9, 2012 1251 Comments Off on Corn Report: May 9, 2012
Crop Reports

Corn planting ranges from 50 to 95% complete; provincially corn planting is estimated at 80%.  In most areas rainfall has not been intense and soils remain in good shape despite large acreages without significant residue cover.  Corn requires about 180 CHU to emerge.  Corn planted April 16-20 is emerging this week.  Most reports suggest that emergence and seedling vigour are…

Corn Report: May 2, 2012

Greg StewartGreg Stewart May 2, 2012 1230 Comments Off on Corn Report: May 2, 2012
Crop Reports

Corn planting is 20-90% complete depending on the area of the province; provincially planting is estimated at 65%. Some of the early (i.e. April 5-15) planted corn had emerged and the cold temperatures of April 27, 28 & 29 froze the above ground tissue. However, to date, growing point and seed integrity remains high in the early planted corn. Although…

Corn Report: Week of April 23rd, 2012

Greg StewartGreg Stewart April 26, 2012 1238 Comments Off on Corn Report: Week of April 23rd, 2012
Crop Reports

Depending on the area, 10 to 60% of the corn crop has been planted. Provincially corn planting is estimated at 35%. Soil conditions remain dry and friable in most areas; the lack of soil moisture is an increasing concern and has forced deeper planting especially on light textured soils. Cold temperatures and rain/snow mix has caused some concern over seed…

Corn Report: Week of April 16th, 2012

Greg StewartGreg Stewart April 19, 2012 1321 Comments Off on Corn Report: Week of April 16th, 2012
Crop Reports

Depending on the area, 5-30% of the corn crop has been planted.  Soil conditions have been very good. Cool temperatures (especially at night) in the last week have slowed the emergence process. If drying trends continue growers are advised to be cautious with secondary tillage that is too aggressive (too deep, too many passes) and causes excessive drying.  Yields decline…

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