THE ART OF FARMING
Mid to late April plantings are just fine provided soils are suitably fit for planting.
The unfortunate part is that there may be areas in large 60-70 acre fields that are not fit.
When you proceed to plant these areas anyway you run the risk of creating subtle compactive zones in the soil profile.Sidewall smearing can become a real issue in restricting early season root development as well as lower seedtrench compaction which will restrict a young seedlings roots from penetrating to lower soil depths.
The result is a lack of even crop development.Certain tight areas may exhibit yellow due to slow N nitification or slower seedling root development.Other even tighter areas may exhibit N denitrification due to cooler and pastier soil conditions.These tighter soil condition areas will also be slower to drain when any rainfall event occurs.You must be cognizant of the fact that the roots of young corn seedlings will not grow into cool,moist pasty soil conditions.They will produce as many lateral roots as they can until soils dry enough that they can grow deeper.The unfortunate part of this is that any soil restrictions impeding lateral root development will stall out a young corn crop hurting its yield potential.

WHAT IS IT ?

Wheel Traffic Compaction - Agricultures #1 Enemy
The plant on the left in the above photo comes from an 100 ft section of row where the tire of the row crop sprayer unit ran.
If you double click on the above photo and check out the centre corn row you'll see where the tire of the sprayer unit ran on the corn row.
The above photo is a side angle shot of the same corn row showing stunted smaller plants that are expressing a purple florescence because of their restricted root development.
Tightened soil consolidation caused by the sprayers weight load is making these corn plants find it difficult to find air space in which to push their roots.This points out very clearly how crucial it is to avoid soil compaction.

SIDEDRESSING SHOULD ALWAYS BE COMPLETED BY 6 TRUE LEAF CORN
To optimize corns yield performance sidedressing should always be completed by the 6 true leaf stage.
The above grower is cutting it pretty close.There is always a short lag time between the application of sidedress N and the uptake by plants.
By the time corn reaches 6 true leaves growth is becoming much more accelerated and Nitrogen usage per day is reaching 3+ lbs.It is important that the crop is on full feed by this time.

Not only is corns N use requirement growing but the cell division of ovules determining kernel row set occurs within a week to 10 days of corn reaching 6 true leaves.Better kernel row set is initiated when corn has all the N requirement it needs at this time.


Another good reason for making certain that sidedressing is completed by the 6 true leaf is to avoid root pruning and the increased loss of headland plant stand that can occur with late sidedressing.When sidedressing starts at the 3 true leaf stage it provides a good safety measure in assuring that all your corn will be sidedressed by 6 true leaves and on full feed to optimize yield performance.

PURPLE CORN GENERALLY SIGNIFIES SOMETHING RESTRICTING NORMAL ROOT DEVELOPMENT
Anything that restricts normal root cell divison can cause a hybrid to cast a purplish flourescence
in its upper canopy.Cold soils, wet soils, compacted soils, root pruning from insects, fertilzer burn or anything else that can restrict a plants root development
can cause a hybrid to express PURPLE CORN SYNDROME.
The corn in the above photo is expressing a purplish fluorescence because of all the wet weather we've been experiencing in the last 3 weeks and the side-hill seep that is occurring because of it.Side-hill seep will keep soils much cooler and wetter than other areas of a field and the plants root growth and development will be slowed.As a consequence the anthocyanin genes that a hybrid carries will cause the accumulated sugars in the above ground tissue to trigger a purplish florescence to be cast.
The amount of purplish florescence cast is a result of the number of anthocyanin genes a hybrid carries.Hybrids can carry anywhere from 2 to 8 genes.Those that carry more will cast more purplish florescence than those that carry fewer.
When growing 2 hybrids side x side it is possible to have one hybrid express a lot of purplish florescence and the other one to express very little.When you see this don't get caught up into thinking that the hybrid expressing less puplish pigment is not being hurt by whatever soil stress is causing the slower root growth.Labratory work has shown that hybrids that don't express much purplish florescence in their canopy under the prescence of root restrictions are slowed in their above ground cell divison to the same degree as hybrids that express a lot of purple anthocyanin expression.The key is to assess what factors are causing the corn to purple in the first place.Once you resolve those factors you will be on your way to producing higher yielding better performing crops.

ASSESSING OFF COLOURED FIELDS
A number of corn fields across the countryside are expressing a degree of yellow and shorter statured growth that has many growers asking what is going on with their crop.In many instances this yellowing takes on the presence of what visullay appears as Mn, Zinc , S, or Mg deficiency.

Though the crop may be currently expressing what appears to be a micronutrient deficiency of one kind or another I don't believe that most soils are actually short of these micros.What I do believe is that the crop is temporarily experiencing an environmentally induced micronutrient deficiency.

The abundance of rain that we have been receiving over the last 2-3 weeks has temporarily curtailed downward root growth thereby diminishing the plants ability to extract the necessary nutrients for normal growth from the total soil volume.When this occurs the reduced uptake of N as well as micronutrients makes the plant take on a pale green to limy yellow colour.

Don't be overly alarmed at this temporary yellowing in your corn crop.Roots just need to be given an opportunity to explore more soil volume to search out the necessary nutrients that will turn your crop back to a vibrant rich dark green.



Give the crop a week to 10 days of drier warmer weather and voila roots will proliferate to a deeper depth finding more available micronutrients and utilizable Nitrogen

Growers will be amazed at how readily the crop will take on a new resurgence of growth and turn from a dreaded off coloured limy green to a rich healthy vibrant green.

DON'T GIVE WEEDS THE UPPER HAND
I cringe every year when I see weed pressures like that above robbing growers of precious yield.To optimize the yield performance of corn it is Critical to keep Weeds out of it between the 3 - 8 leaf stage.
Roundup Ready Corn was developed to give growers crop safety and more options to control tough to kill weeds.Unfortunately the fact that Glyphosate can be sprayed on large corn without any deleterious crop injury has lulled too many growers into a false sense of security.
Yes large weeds can be controlled by late glyphosate applications and by the time harvest rolls around you can think you were a genious by how clean your crop is BUT the fact remains that yield was lost.Though the weeds in the above photo have been controlled they were left too long and they will have hurt this crops yield performance.DON'T LET THIS HAPPEN TO YOU !
The highest yielding weed control system that can be employed is to spray two applications of glyphosate on glyphosate resistant corn.The first spray application should be made at the 3 true leaf stage and the second at the 7 true leaf stage.Why anyone would leave this kind of weed pressure to impact their crops performance is beyond my comprehension.
Growers who feel that this could put too much reliance on the use of Glyphosate can achieve the next highest yield performance with a pre-emerge spray application followed by an in crop application of glyphosate at the 5 - 6 leaf stage if needed.
Another option that can be successfully used by growers is to spray Glyphosate at the 3 true leaf stage and lay down a grass or broadleaf tank mix residual at the same time.
Whatever you do please try to avoid letting weeds getting an upper hand.
Glyphosate resistant corn is a wonderful technology but its got to be used properly in order to maximize yields.

COULD THOSE BE CORN ROOT NEMATODES ?
YOU BE THE JUDGE.
DOUBLE CLICK ON THE PHOTO TO THE LEFT TO ENLARGE IT and THEN TAKE A CLOSE SCAN OF THE ROOTS TO SEE IF YOU CAN DETECT ANY SWOLLEN CYST LIKE STRUCTURES.
DO THE SAME THING WITH THE PHOTO BELOW.CAN YOU SEE ANY SWOLLEN CYST LIKE BULBOUS STRUCTURES ON THESE ROOTS?
PLANT and SOIL SAMPLES HAVE BEEN SENT INTO THE LAB FOR CONFIRMATION.
WE'LL KEEP YOU POSTED.
The smaller plants to the left are suspected to be infected with corn root nematodes.All plants should be the
size of the plant on the right.
Suspected field of corn root nematodes.
Corn root nematodes have been far more recognized and discussed in the US but it just may be something that we will have to start talking about and diagnosing here in Canada.