Soil Field Condition vs Lab Tests

These pics are examples of WW crops from two different tillage systems.  Both of these crops look pretty good as of April 13th, 2021.

<-----  Pic on the left is an example of 2021 WW on long term conventional ground.  This  crop was seeded on chemical fallow grnd.

<---- Pic on the left is an example of 2021 WW on ULD grnd.  This area was seeded too shallow and got a late start.

        This winter/spring I had a unique opportunity to run a lab test on two soils that have very different history.  One soil has ~30 years of no-till, with the last eight years being ultra-low disturbance no-till.  The other field, a couple hundreds yards away has a history of one hundred plus years of conventional tillage/cropping, with no no-till history.  Both locations were fairly level with low erosion from weather, although a difference in tillage erosion would be apparent.  The no-till field has a large amount (mat) of residue, and the tilled field has a small amount (a lot of open ground) of residue.   I had high expectations of seeing a dramatic difference in OM, EC, BD, Respiration, and some differences of several macro and micro nutrients.  WHAT A DISAPPOINTMENT!!  Some numbers were the same, and some showed slight differences, but all in all, no revelations.  This lab is not the general run of the mill type that we are all accustomed to.  I have used this lab for a couple of years for different projects. 

    Physically there is a world of difference between these two fields.  April 13th with no measurable rain since March 23rd the ULD grnd was soft to walk across, where the tilled field was hard under foot.  Sinking a 1"diameter soil probe into the ULD field was easy, down the full 4 ft length of the probe, where the conventionally tilled field was very difficult down to ~18", where resistance eased up (maybe even softer than the ULD field in the lower 2'.

        Why didn't the lab show differences as expected?    Two things come to mind.  1)- In my mind this was such a no brainer that I was careless taking the samples.  My process of taking an undefined slice of soil using a narrow trenching shovel was bad technique.  A lot of possible error could result.   2)- This supports my comments on earlier posts about lab testing, and difficulty in trying to show value of no-tilling through our long recognized lab protocols. 

     I'm convinced that no-till deals primarily with the physical component of soil health, but secondary to other processes like biological diversity and nutrient recycling.  Biological activity has to be helped with cover crops and possibly reintroducing microbiological species through well prepared compost and compost teas.   No-till is significant in improving soil drainage, and it reduces destruction of soil organisms community life.    No-till is the first step required for us (in the Palouse) in developing a healthy soil.  With few exceptions, our environment will not support tillage and develop a healthy soil.   Comparing infiltration rate, wet aggregate stability (SLAKE test), visual soil structure, and earthworm count is easy to do and shows dramatically what no-till brings to the table relating to soil health.  Bulk density should be an easy comparison, but the penetrometer is effected by moisture content, soil type and other factors that vary from point to point.   So, what do I conclude?  As many of my earlier posts mention, a no-tillage farming system, is very effective in building soil structure over time.  A no-tillage farming system, when coupled with high surface residue (soil armor) is very effective in controlling erosion from tillage, water, and wind.  A no-tillage farming system is helpful in slowing evaporation when coupled with a protective mat (soil armor) on the ground, and even more effective if also coupled with standing stubble.  Moisture is lost principally through evaporation, not crop production.  Keeping soil surface temperature down, and a low wind velocity along the soil surface, saves moisture that can be used by the crop.  Another benefit to a no-tillage system and heavy mat of residue is reduced competition from weed species, either broadleaf or grasses.  We see it consistently year after year when comparing our neighboring fields with either conventional tillage or high disturbance no-till.  Unfortunately, we still have to apply herbicides like everyone else.

WHY WE STILL FALLOW

      Why do we still have fallow in our farming system when we have the equipment to direct seed was, in essence,  the question I received from a recent post.  We have no conventional tilled fallow, but do have chemical fallow.  
       I've concluded the short answer is TRADITION.  It's part of my family culture. There are plenty of university studies indicating how poor the moisture efficiency is with fallow, and how destructive fallow is to our economic base (the soil), and to the environment, however, we have learned to farm with it, getting good yields, and that is a comfort level of it's own.
      There is no question in my mind that, for the future, we would be better off if we broke tradition and looked at building up our soil health instead of continually farming it into oblivion as we have for the past 100 plus years.  That; however, puts us into the realm of the unknown, associated with higher risk.   Our forefathers used cover crops to a certain extent, but never to the extent of soil sustainability.  Sweet clover was planted for nitrogen, then ploughed down.  Many operations rotated cattle or sheep onto crop ground and seeded pasture, but those "soil building" attempts were negated by grazing those fields into the dirt.  As time went on, cattle left most of the operations, ground  has been consolidated, and transitioned into a monoculture of wheat.  The little our forefathers did understand about soil health and the role of cover crops was hampered by the equipment available.  To build soil health we have to remove our traditional fallow practice, and introduce more diversity of crop cultivars.  We will probably need to introduce cover crops to help with that diversity.  Chem fallow is a no-brainer for those of us that have been doing it for a couple of decades, but even that "conservation practice" is used by a small minority of the community as a whole.  I'm seeing more delayed tillage where the first one or two operations are application of chemistry, then tillage follows before planting.  This has morf'd, in some cases, into the two pass system (or 3-4).  That looks risky to me, but I've seen some pretty nice crops develop from that system.  It's all about moisture and it's timing.
      Even the mention of introducing cover crops leave people walking away shaking their heads.  It's just too risky.
      The next step for our operation to reach the goal of no fallow will probably be Green Fallow, --and that may be as far as we wish to go.  I'm starting to see where the "fallow" period my be the staging for the next cash crop.  The "fallow" will be planted with a diverse (designed plan) mix of cultivars that will bio-drill, add root mass, add nitrogen (if needed), and scavenge nutrients from the depths of the soil profile.  I'm reading where most (or all) the plants nutrition comes from the top 18" of the profile, and roots drive deeper for the purpose of accessing moisture.  If this proves out, we need to rethink how and when we apply nutrients in the short run, and plant appropriate cultivars to replace commercial fertilizer in the long run.

Residue & Wind

           The fall of 2015 we had several wind events of short duration where winds gusted to 30, 40 and 50mph, depending on the event.  I never gave much thought to it at the time; however, this spring it was a shock to see a couple of bare areas on SE slopes.
           This field started out with good standing cover of stripper headed spring barley that was chem fallowed, and seeded to WW around September 20th of 2015.  We missed the moisture so much of the field did not emerge until late October or early November.  This is a scene similar to what I experienced 30 years ago, in this same field,  when I mistakenly thought that it was good to mow standing stubble early in the season for ground cover.  it didn't take a lot of wind to deposit residue drifts up to a foot deep on our NE facing slopes at the time.  Only once did I make that mistake.  After that, I mowed a short time prior to seeding, leaving standing stubble most of the fallow year.  We needed to shorten the stubble to minimize problems drilling.

        The pic below shows where I chopped a hole in the packed residue drift.  The drift was  4" deep and very dense packed.  It was easy to cut this hole with my hand tool.  Walking on this was like walking on a firm sponge.  Very few WW cultivars emerge through this dense, deep mat.  As may be expected the soil surface was very damp.  Soil was cool but not cold, --probably in the low 60's.

       The pic below shows a WW plant that made it through this dense residue pack.   Close up shows that the plant received light nearly to the ground level.  I don't have a clue as to why a few cultivars emerged where the vast majority did not.

  

Hopefully, we won't have a repeat of these wind events for years to come.  One event in late November dropped our cast iron flag pole my grandfather put up over 100 years ago.  Winds topped 50mph.  Very little damage was noted except for the flag pole.

CHEMICAL FALLOW

[Update 6/14/16] -- All of the winter canola died during the winter.  It didn't make any difference whether is was platter size or just emerging.  We planted SW on most of the acres and Billy Beans on the remainder.  Both crops received heavy damage from a June 12th, 28 degree night, --not a great year.  The spring peas was the only crop damaged to the extent that multi peril crop insurance kicked in. [Update 10/30/14] -- Finally all our WW has emerged.  It appears that we will get most of the canola out of the ground.  We had all the pieces in place for this kind of summer and fall, but we didn't execute very well.  We got about 40% of the canola emerged timely in mid-late August, and about 50-60% of the winter wheat emerged timely mid September.  We currently have 70-85% of the canola emerged, but other than the plants emerged timely in August, it's doubtful the remainder will survive the winter.  It is still emerging.  Post analysis:  The hot weather, lack of good early soil profile moisture allowed seed depth moisture to thin earlier than expected.  The "best" residue areas were OK, but "good" residue was not.   We should have seeded the canola at the end of July instead of mid August, and we should have seeded the winter wheat a week earlier (end of August instead of first part of September).  If the ADF system had been working consistently, we may have still got 80-90% of each crop emerged timely.  Weed pressure is low in both crops.  
        We may have an opportunity to see what the yield loss may be between timely emerged wheat and that which emerged 30+ days late.   Years ago when I was regularly seeding the second week of October, I estimated that I consistently lost 15-20 bushels per acre compared to some of the neighbors.
[Update 9/20/14]
       --- Soil that has cover is noticeably cooler, and moisture stays in the seed zone longer in the fall.  It appears to be proportionate from 0 to 100% cover as to where the moisture line is at any given point of time in the fall.  Observation this fall supports an earlier post about a 1970's unpublished research project (Soil Moisture posted 8/19/12).

          I have started observing and digging in various fallow fields to see the differences that may show.        I have been in a limited number of fields to date, but what I am finding is what I have learned to expect.  "If you see dirt you don't have enough residue".  We have had, over the last two weeks, high temperatures (high 90's and a few over 100) accompanied with a lot of wind.
         Conventional fallow is hot and dried as deep as it is worked.  One field was worked shallow (≈2") and moisture was thinning below the worked area.  Another field was worked to 4"and to a finer texture and when moisture was reached it was good.  Powder dry and no (0%) residue, both of these fields will likely endure severe wind and water erosion before the crop is harvested in 2015.
         The chemical fallow fields in the area are either mowed short or have thin short stubble following harvest.  In both scenarios, they have insufficient residue to hold moisture in the seed zone.  The fields I checked were dry to ≈1.5" and thinning moisture below.  Without added moisture, it will be difficult to get a stand of winter canola, and by fall, it will be difficult to get a stand of winter wheat.
        In contrast, our field that will be seeded to winter canola, is in great shape.  We have a thick mat of residue on the soil surface, and standing stubble (36").  The soil is cool and the wind has not been whipping across the surface.  The combination of surface residue and tall stubble leaves us, currently, with moisture within 0.5", and much of the area has moisture at the soil surface.  There are holes in the field where the moisture is deeper, but 95% of the field is great at this point in time.
        We have another fallow field.   Part of the field was mustard in 2013, but the majority is CRP that we started the takeout process in July 2013.   I am including some pics with narrative to explain what I viewed.  It's notable that  the soil surface of this field whether crop or CRP is full of worm castings.

The pic above shows a lot of residue but there are significant holes in long narrow strips where dirt shows through.   A guestimate would be 90% coverage, maybe 95%.  The 2013 crop was mustard that yielded below average.  It was seeded into very dense 2012 standing winter wheat stubble with a cross-slot drill.   The area in this pic was over 120bu/a.  Without ground disturbance the winter wheat (Brundage 96) stubble has stayed pretty good.  There is no mustard residue to be seen by the casual eye.  The mustard stalks were mowed following harvest.  The operation was mainly cosmetic.  With all our residue from 2012 the mowing appears to not have hurt the moisture bank.

This pic shows one of the narrow strips mentioned above where dirt was visible.  There is residue in these spots, but you see dirt.  You can see the moisture line, and it is 1.5" below the soil surface.  You can also see what is probably the transition zone where moisture is thinning.  With no standing stubble, and inadequate residue, this spot took the full force of wind and sun.  1.5" below surface is where I found the moisture line in all the chem. fallow fields where I looked.  In all likely hood, the moisture line will continue to drop.  We are in the third week of July.  It's a long time to our normal seeding date.  Rain will be needed to start a crop this fall.  The dry looking crumble soil is all worm castings.

This pic shows the condition of most of the field.  It's included in the first pic above.  Heavy mat of residue, but no standing stubble.  The moisture line is at the surface, and it is good moisture --not thinned.  This demonstrates that residue can hold moisture and armor against high temperatures and high winds in Uhlig class soil.  The down side is, that this level of surface cover will be challenging to maintain.  

This pic is typical of the CRP/fallow that comprises most of this field.  Good residue; however, it's inadequate to hold moisture . The top 3-5" of soil  is made up almost entirely of worm castings.  They have been working without interruption for 26 years.  The moisture line on this hilltop is at 1.0".  That is better than standard chem fallow but not as good as heavy residue shown in pic above.  If you look closely, you can see dirt among the standing residue.  The standing residue is only about 12-16" tall, and much of the surface shows dirt.  

         This is a good piece of property and we are excited to start enhancement of the microbiological community that's underfoot.  This field is our best opportunity to develop a sustainable cropping system.  25 years of CRP is the kick start.  Now we have to gain the knowledge and wisdom to work out a crop rotation, and develop a plan to incorporate cover crops where practical, and possibly inter-seed an alternate crop with our cash crop, and hopefully in the not too distant future, remove fallow from the system in this 15-17" rainfall zone.

WHEAT/BARLEY/FALLOW -- MAY BE POOR D.S. ROTATION

Summary: (updated 11/4/13)

       Our operation has been Direct Seeding for over 20 years.  The rotation for most of those years have been a three year rotation of winter wheat - spring barley or spring wheat - chemical fallow.  It appears this rotation, using Direct Seed, will lead to compacted layers near the soil surface.  Wheat and barley have a fibrous root system that don't have a lot of push.  To remove compacted layers, without  cultivation, our crop rotation needs to include a cultivar with a stronger, deeper root system.

Detail:

       The old ways I learned, which was associated with conventional farming in the 50's, 60's,70's, and 80's, like: a-- don't seed prior to Sept. 15th because of root diseases and aphids,  b--wait for rain to get one last whack at downy brome grass prior to seeding fall wheat, was costly for us in the early days of our Direct Seeding.  It took years to move past that engrained mind set.

        The winter wheat had normally been 10-15 bushels below the high yields in the area.

        One component of winter wheat yield, is, growing time.  In Direct Seeding, our yields joined the top yielding fields in the area when we started seeding early to catch the moisture for early emergence.  Our criteria now is to seed into moisture even if that is August.

        Spring barley and spring wheat crops have not made that break through for us yet; although recent information relating to compaction, and seeding depth may change that.

       We had concern about our current (2013) spring barley crop.  This crop was seeded into 90+ bushel, 40"winter wheat straw left by a stripper header. that did not get prepped properly last fall or this spring with timely applications of glyphosate.  We fully expected to find a serious soil borne disease issue (Rhizoctonia) from the "green bridge".  Two university scientists found little evidence of that; however, they did find that, at shovel depth, there were compaction layers where roots were growing horizontally instead of vertically.  Also noted was the fact that seeding depth was too shallow, which allowed wetting and drying of the seed and poor positioning of the plant crown.

Since research has not found any real problem with plants growing in heavy residue as long as the seed is positioned well in the soil, plant diseases are managed, and there is no light interference from standing stubble, we should be able to grow high yielding spring crops in heavy residue.------>   By:

1-Adding a deep rooted cultivar (chick pea, mustard, canola, alfalfa) to our crop rotation on a regular basis to remove compact areas that restrict vertical root development.

2-Being more diligent in watching field conditions and make depth adjustments for proper crown development.

3-Leave no standing stubble following seeding of the spring crop.

4-Seeing that we maintain crop rotations and field sanitation to avoid plant diseases.