ROD WEEDER VS PLANT HEALTH

This post relates to an earlier post [TILLAGE VS NO TILLAGE 3/2/20].   I had a very rare opportunity to compare crop response between using the rod weeder and not using the rod weeder.  In the pic to the left, everything is the same except seeding date and use of the rod weeder.   The yellowish tint (background) is the result of the crop roots growing in a low oxygen environment created by the the rod weeder.  The crop in the foreground did not have a rod weeder used prior to seeding.  The rod weeder, a regularly used tool with conventional tillage systems, creates a compaction layer where the bar presses and smears the soil it comes in contact with under the bar, while at the same time fluffs and loosens the soil that goes over the bar.  Compaction layers slow the movement of water into (through) the soil profile which can, and in this case, did, cause the moisture content to remain above the field capacity for a significant amount of time.  This excess moisture replaces oxygen in pore spaces and leads to an anaerobic condition.  An Anaerobic soil condition increase growth of organisms normally associated with decreased plant health.  Aerobic soils increase growth of organisms normally associated with promoting plant health.

    [Feb. 10th pic]  This pic (from the yellowish field) shows a very wet root ball.  I could not remove the dirt for a decent pic of the root structure.  The roots were bunched with few roots extending deeper into the profile.   If you enlarge this pic, and compare with the one below,   you can detect more yellowing of the plant leaves associated with oxygen deprivation compared to the pic below.
     How this condition will effect overall yield compared to the crop in the pic below will be hard to assess because of so many variables inherent with two different operations and the weather from now to harvest.   An example, --two recent events of very cold nights, one on April 13th @ 10ºF and the other April 17th @ 19ºF, and since then, many mornings with temps in the mid to upper 20's.  When scouting on April 14th, the crop in the pic above was not jointing, while the crop in the pic below was jointing.   The seed head associated with jointing could be vulnerable to freeze damage.  During these events, the younger crop was showing serious leaf damage with color change and laying flat to the ground,  while the older crop showed no leaf damage.  Symptoms of cold damage in the area were reported as related to cultivar type, and plant size.

     [Feb. 10th pic]  This plant shown on the left is from the crop in the foreground of the pic at the top (dark green).  The roots are quite  damp but I was able to knock the dirt ball loose, exposing the root structure.  The roots extended deep into the profile with no root mass near the crown of the plant.  It was obvious the moisture was draining more quickly into the profile.

     There is one more point related to water infiltration that I want to make, --that is, comparing the conventional fallow based system (the three pic's above), too a bordering field with a long history of direct seeding shown in the pic below.

[Feb. 10th pic]
    The pic on the left shows winter wheat growing in a long term ultra-low disturbance direct seed field with surface armor well above the 100% NRCS residue chart.   Notice how much dryer the roots look in this pic compared to either pic above.  The wet dirt was easily removed, leaving much of the root system intact.  The roots are growing and elongating very well.

    This post brings up another subject, --fall tillering compared to spring tillering.  I'll address that subject in another post.