Tillage to Reduce Herbicide Resistance

 A recent posting in "Weeders of the West" a WSU blog [https://smallgrains.wsu.edu/weeders-of-the-west/2021/06/21/occasional-tillage-and-herbicide-resistance/ ] stirred me to make this posting.  The link above will take you to their posting that I am referencing.  For about 5 years I have been hearing WSU weed scientists introduce "occasional tillage" back as a practice to reduce herbicide resistance.  For those of us that are die-hard no-tillers, that's like throwing gasoline on a fire, --it makes no sense what-so-ever.

      I could rant on this all day, but I will try and limit my comments to a few references in the posting.  I’ll start with a statement of my position.  I’m not quite as old as dirt but I was around before there were synthetic chemistry or fertilizers for our crops.  I have spent most of my life stirring dirt, destroying my little portion of the Palouse ecosystem.  For the last 30 years I have been trying to figure out how to repair that damage.  Since the year 2000, research on soil health has grown astronomically.   It's to the point where I discount (not reject) research findings that are more than 5 years old.

--What is soil health?  I find that it has many different parameters depending on who is speaking on the subject.  I can accept Huberto Blanco-Canqui’s findings for the high quality, deep soils that probably make up their research sites.  If the soil is deep, with high OM, and a near neutral pH, then, an occasional stirring probably is a minor setback to the ecosystem.  Soils with a high level of biological life have the capacity to rapidly rebuild after a destructive event.  Soils with low levels of biological life do not have that capacity, so rebuilding is slow.  The post mentions tillage to break up compaction and reduce stratification of soils.  Back in the 70's, WSU was researching ways to mitigate tillage compaction. Compaction was recognized as a problem through the use of moldboard plows, disc harrows, and rod weeders.  I had fields where four tillage pans could be identified.  Chisle plows and heavy cultivators were proposed solutions.  Compaction layers were found to be moving lower in the soil profile because chisels and cultivators broke soil aggregates into finer particles that moved deeper into the profile.  Deep chiseling and subsoiling was considered, but rejected because it was feared that compaction layers would move lower than implements could reach.  We are still dealing with compaction layers in our soils.  It has been demonstrated that we can influence compaction and stratification of our soils with plants and biology.  We need to figure out how to incorporate them as part of our cropping practice.  There are plants and macro fauna that are very good at these tasks and leave a better long term effect.  Except for small acreages, soils in the Palouse, in general, are badly degraded from erosion from years of cultivation (erosion from cultivation, water, and wind), and from being mostly a monoculture cropping system.   Any cultivation is a major setback to our ecosystem.  I compare "occasional tillage" to burning your house down every few years.  Many of the soil biological structures don’t rebuild very quickly in our climate and cultural environment.  Tillage and fallow is a real downer for soil microbe communities.  Biological networks are sliced, diced, burned, starved, --and are slow to recover from a major disruption.  

--What is “occasional cultivation”?  I have never heard a followup explanation as to what this term meant, or how it would extend a herbicides useful life.  Retracing my memory of tillage I don't think there is such a term as "occasional cultivation.  Nearly every year I see a farmer do reduced tillage, and weed escapement is always a problem, which results in more tillage, or chemistry applied with less than desirable results.  My experience is that tillage bury’s seed, of which some emerge and the remainder stay in the soil bank, safe, for later emergence.  Tillage destroys OM and emits CO2 and H2O into the atmosphere. Tillage degrades the soil through erosion, compounding our problems.  I find that, the less the disturbance, the fewer the weeds that compete with the crop.  I regularly see this in my fields.  A mat of surface residue along with no disturbance is preferable.  I often wish my equipment could levitate over the fields leaving no track.  Wheel tracks are where the weeds are.   An expanded crop rotation, and rotating appropriate chemistry will be more effective than tillage in reducing herbicide resistance in weed populations.

        --The ultimate goal will be removing synthetics from crop production.  As time passes this will happen because of weed resistance, environmental regulation, or cost.  These pressures will force us to learn to incorporate cover crops, do inter-seeding, and use companion crops in our production of cash crops.

        --Disciplines within soil & crop sciences need a closer relationship.  Weed scientists need to look for solutions through microbiologists, crop specialists, and other related disciplines.  Books like “When Weeds Talk” by Jay L. McCaman have a lot of potential for weed management, by manipulating soil chemistry and biology through plant cultivars.  Research by crop specialists working with cover crop cultivars, intercropping, and companion cropping are showing some real promise in increasing yields and reducing weed competition and diseases in cash crops.  Cropping problems need to be approached through coordinated discussion and research by cooperating disciplines instead of individual disciplines reverting back to old failed practices. 

2016 SPRING CROP UPDATE

      SUMMARY:  Nothing compares to the CrossSlot for direct seeding into adverse seedbed conditions.  Our 2016 crop consists of WW, WP, DNS, SB, SP, M.  All the crops emerged well with good populations, and growing.  Our crop year is starting out 1-4 weeks early, depending on what indicator you use.  The lilacs are 4 weeks early, cheatgrass is ≈1 week early,  The Iris are 3 weeks early.  Our moisture gain faltered in April with only 0.5"and nothing is showing in May to this point.  Warm weather is upon us, and stored moisture is depleting.  This may be another year that will tell us more about the moisture saving aspects of tall residue, ground surface cover, and using a ULD seeding system compared to the bare soil with conventional tillage.  I have been watching different operations in the area.  Conventional tillers have gone over the fields with 5 trips, and some with as many as 7 trips to get their crop in the ground.  We have sprayed and seeded.  Our crop stands are better than most, and comparable to the best.  With CT and the closer drill row spacing those fields (in their better ground areas) look fuller; however, studies have not shown yield increase with that system, --everything else being equal.  The closer row spacing normally will canopy quicker offering the potential of lower moisture loss from evaporation on bare soil.  With all this being said, there are times that I wonder if 8" row spacing would have been better for spring cropping, even with the CS.

WINTER WHEAT (WW):

       We are very pleased with the progress of the crop at this point in time.  We have two ages of cultivars in the field.  One emerged on time near the end of September and is tall and a good dark green color.  The other emerged in November. It has good growth and a dark green color but is 6-8" shorter (this includes the CC winter wheat which has the same height, but a little lighter in color).  Very surprising is that both cultivars are in the 8 leaf stage.  What did the older cultivar gain in the 6 weeks extra growth other than longer internodes?  We will check the head size and fertile meshes when the time comes.

         The cover crop area WW has good height and color for it's late start in the fall.  It will be interesting to see what the yield lag may be between the CC and CF winter wheat.  We have a long border between the two that will give us some indication as to yield difference on comparable soils.  The CC field generally has much shallower soils than the CF field.

         Another question without an answer:  --Our small wheat, which went into the winter in a similar condition to most of the other WW in the area came out of the winter in better condition.  Ours came out of the winter growing, while most of the crops around us did not (and in some cases, have not), --why?  With a relatively open winter and significant rainfall, it was expected that N would have converted and leached down into the 2-3-4 foot level of the profile.  Most of the little wheat in the area acted as if that were the case.  Ours did not, --why?   I can only assume that our years of no-till played a role; however, our soil tests don't show the qualities that would lead to that conclusion.  Recent discussion with Dave Huggin's from WSU, reinforces my belief that there is a lot about soil tests and their interpretation that we don't understand for soils in our environment.  The biological tests I have taken show our soils in poor condition including it's structure; however, the Slake test shows great aggregate stability from our years of no-tilling.  Experience has shown me that our infiltration is much better, than the soils around me that are conventionally tilled.  Other than the Feb. 2014 thaw, we have had no water leave our fields for years, while the conventional tilled fields regularly have water running down the slopes and into the ditches during storm or winter events.  There is something going on here that is not explained by our normally accepted testing procedures.

AUSTRIAN WINTER PEAS (WP):

[Update: May 13]  We are applying Bassagran on the WP field that will be harvested.  Jim Hill Mustard has bolted and blooming.  A few purple winter pea blossoms are showing on the south exposures.  Our earlier application of Select II for grass weeds did not work well on the borders.  Downey Brome will be with us in the next crop.  The Rattail Fescue under the CRP, eyebrows and some area on our borders was missed as well.  Next year we will post seed/pre emerge Sharpen and Tricor 4F for weed control.  I have spotted two areas damaged from a cold night at the end of April.  Neither weeds or WP's have regrown.  Because of the poor growth of  the mustards, I have some concern there may be chemistry reaction rather than frost.

      We seeded WP (winter peas) last November in what was termed dormant seeding.  You want them seeded deep.  Austrians are a dark speckled little thing and I found them difficult to locate in all the duff.  The ones I did find were much shallower than our intended 2-3" which was cause for worry.  Our understanding at the time was that the peas needed to break germ before freeze up, but not emerge before spring.  We seeded them at 100#/ac.  They came up thick this spring.  For insurance purposes, since they were seeded beyond the closing date last fall, we had to have the stand evaluated to qualify for insurance.  The count was 3 times more than needed and were calculated at 4200#/ac for yield (under perfect growing conditions).

       The Austrians on SW stubble look great with few weeds.  The Austrians planted into garb ground  are not salvageable.  Between volunteer garbs and a heavy population of several varieties of wild mustard, those acres will not go to harvest.  They were reevaluated by the insurance company so that we could destroy the stand prior to harvest.  Our understanding of how the insurance works is, --since we applied for insurance and the stand was accepted we will pay the premium on all the planted acres.  The yield was recalculated showing the garb ground had the potential of ≈2100#/ac.  At harvest this yield calculation will be added to the harvested amount for yield history.  We now are free to do whatever we wish for those garb/austrian acres but those acres will not be eligible for insurance in 2016.  The garbs are starting to bloom, and the austrians are in the thirteenth node, standing about 6-8 inches.  Both legumes are forming an abundance of root nodules.  What to do???  Our current thought is to manage the acres as a cover crop.  We have a fair diversity of plant material, --garbs, peas, and several varieties of mustards that are rooting deep in great abundance.  There is some dog fennel, a few fiddle neck tar weed, some lambs quarter, some prostrate knotweed, very few russian thistle, some china lettuce, and few if any grass plants.  We don't want the weeds to seed out, nor the peas to go beyond early podding for maximum N development.  Since this acreage is planned for a spring cereal in 2017, we are not concerned about the required destruction by June 1st for summer fallow yield protection for 2017 WW.  Current thought is to max N development from peas and garbs.  If weed development comes on faster than the legumes we'll mow the acreage and manage for the regrowth.  If the legumes reach the proper stage prior to the weeds, we'll apply chemical and hold as CF until spring of 2017.  These acres won't look pretty because we will leave the residue stand.  We're hoping to have a mat of pea vine but the austrians appear to be growing slowly.  We had a frosty night a few days ago and the top node of the peas turned yellow, slowing them up.  The wild mustards are having a banner year.  Since we have been killing them for 100 years and the population doesn't seem to decrease, I'm not worried about them developing some seed.  They are easy to kill in any grass type crop. 

       SURPRISES:  ---after years of clean CF through timely applications of Rt3 and Valor, and having clean appearing grain crops, mustards have populated most of the garb/austrian ground with high populations. Russian thistles and china lettuce, although present, have a very low population.  That's a testament for using Valor in the fall to combat those two aggressive weed species.   ---grassy weeds are nearly nonexistent, showing that grass control chemistry for our broadleaf crops are killers, not suppressors.  Our past rotations with only small grains and CF, Downy Brome was always present in yield depressing amounts.   ---the number of billy beans (garbs) that took root and grew this spring.  Weeds are problematic, but we have chemicals, swathers, and pickup heads for harvesting that type of contamination; however, billy beans are a "grade issue" that is not manageable.  Even if they didn't mature with the peas, it's feared many would end up in the grain bin.  I don't think they would have rooted if there was good surface cover.
       With the next WP crop we will want to consider putting down Tricore 4F following the seeding for broadleaf weed control and maybe the Sharpen as well.

DARK NORTHERN SPRING (DNS) & SPRING BARLEY (SB):       

      Our DNS and SB both have great stands.  They are not perfect.  There are breaks in the rows in places, but mostly the wheat and barley emerged rapidly without winding it's way to the surface.  The stands look pretty much like soldiers shoulder to shoulder on parade,  --straight cotyledons, even color, even height, even fill.  It's difficult to tell how even the stand is from a distance because of the color differences and reflection off the residue.  We seed between 1.5 and 2" deep.  Standing stubble gives us less trouble drilling than stubble laying down.  Stubble  firmly attached to the ground is the easiest regardless of the volume.  Loose or rotted stubble will, on occasion, catch on the spring plate of the blade and drag, causing a pile.  We have a few of these in some of the fields.  They are unsightly.  We'll eliminate most of them over time as we gain experience on setting the drill for the field condition.  We are trending to the long blades for both sides of the disc.  They allow us the most space between the ground and the spring plate when we go for depth.  Currently CS doesn't provide a long blade for the left side with a fertilizer tube.  We hope that becomes available soon.

MUSTARD (M):

      Mustard was seeded next and it has taken longer to see the stand establishment than I expected.  We seeded about 6#/a.  We couldn't find any of the seed except at the opener when stopped.  We trusted that the CS put the seed where we wanted it.  It did.   The bare ground (truck roads, ridges) showed early, while the heavy residue (90u WW stubble) took longer to show.  Stand is good, measuring 6 plants per foot of row on 10" row spacing.  It's not as even a stand as I would like (void, then clump of seedlings).  The plants are not standing like soldiers in line, shoulder to shoulder as with the wheat and barley.  Unless we put a planter together with it's singulation capability, this is probably what we have.

SPRING PEAS (SP):

     Spring Stand Up Peas were the last crop seeded.  Seeded 160#/ac.  Excellent stand in heavy residue.  We applied Sharpen and Tricor 4F, as a premerg application for weed control.

      

(??) MAKING A SILK PURSE FROM A SOWS EAR

Summary:  Cropping a broadleaf behind a broadleaf is problematic if grain is the expected end product.

Background:   Last fall we wanted to even out field acres.  To do this we had to put winter peas (WP) on Billy Bean (Garb) ground.  The remainder(majority) of the WP was put on DNS ground.  The stripper headed bean ground had very light residue, and the stripper headed DNS ground had reasonably heavy residue.
        The ground had little or no weed/volunteer growth when we applied 20oz/ac of Rt3, late October.  We dormant seeded the Austrian WP on the second week of November, placing them ≈2.5" deep.  Freeze up occurred a couple of weeks later.  The information from the breeder was to get the peas to break germ but not emerge until early spring.  Our timing was apparently good, because this spring we had three times the population to qualify for a successful stand, and no weedy cultivars were present.  When temperatures warmed, the weeds and volunteer came big time in the garb ground, but the DNS ground remainder relatively clean.  The only broadleaf chemistry we can apply to the WP is Basagran and that does not have a good reputation. There is good grassy weed chemistry for WP.  A couple of cold nights set the WP back allowing the weed species to become more competitive.
       The pic below shows the WP on the garb ground.  The WP are topped by mustards.  The RCIS evaluated the stand the other day and came up with a projected yield of 2100# if all the stars line up right.  All you can make out in this pic are black mustard and jim hill mustard.  Neither cultivar do we see anymore in our small grain crops, but they waited for a screwed up rotation like this to show their ugly head.  The real problem with this crop though is not the weeds, but the surprising number of garbs that germinated and rooted.  The fear of our supplier is that the garbs will foul the grades making them non-marketable other than feed.  If there had been a good mat of residue I don't think these garbs could have survived long enough to root down.

         The pic below shows our WP crop on DNS ground.  It has good residue cover that includes DNS stubble and the previous WW stubble.  The CrossSlot drill has had a low impact on the stubble, other than laying it over.  If the stars all lineup, this field still holds the potential of 4200#/ac.

SO, HOW DO WE MAKE SOMETHING POSITIVE FROM THIS!

         The WP on garb ground will not go to harvest, --so, what to do??  We could still destroy and reseed to a C4 plant like millet or milo.  We could CF the field, however, the next scheduled crop is in the spring of 2017.  We could manage the field as a cover crop (green fallow).

        We have decided to manage this field as a cover crop, but instead of destroying this mess and seeding cultivars normally associated with cover crops we are going to utilize what's already growing.  ( 6/26/19 update: --After re-reading this post I find that this is not what actually occurred.  Kye couldn't stand this mess so we roundup the field and seeded a 9 cultivar cover crop mix that included --2 canola, 2 mustard, 2 clover, 2 radish and one vetch.  This grew to maturity and was seeded to winter wheat.  The winter wheat emerged but was very small the following spring.  The notable part of this was that I found no noticeable runoff from that field, where our CF field did have runoff.  Our rotation for this field changed at this point.  I'm leaving the remainder of this post more as a "what if".  We may have been able to accomplish a similar result without the expense of seeding the cover crop mix.)  The next regular cash crop will be either spring wheat or spring barley.  None of the weed species currently growing, (primarily black mustard and jim hill mustard, along with a smattering of fiddle neck tarweed, prostrate pigweed, russian thistle, and china lettuce), offer any real challenge for the herbicides we use on spring cereals.  This field has a long history of high populations of grassy weeds (primarily downey brome), but fortunately, following the garb crop I have found NO grassy weeds other than a few plants of rattail fescue.  Chemistry for grassy weeds in a broadleaf crop are killers, -- not suppressors like those available for small grains.  This is a very good reason to incorporate a legume or brassica in the rotation, --removing grassy weed competition.

       Our Reasoning: (for keeping this mess).  WP, with our high population will grow a lot of biomass.  I expect the vines to reach 12 feet long and stand 3 feet or more in height.  Both the WP and garbs are nodulating well, so, we are growing N.  The mustards, which is the primary weed species, are growing long taproots (already slender tubers are 12+inches, and will continue to grow for some time.  They will add significant amount of biomass along with the WP.  We'll watch to see if one suppresses the growth of the other.

         Our goal for this field is: grow biomass, grow N, keep live roots for as long as possible.

---bio mass for surface protection and critter food (worm, and others).

---N for the following grain crop.  (hopefully we can find a way to successfully test for it)

---live roots for making critter food, and boring holes to allow moisture infiltration later.  

         How to manage from this point on (????).

---We'll plan to terminate at full bloom or early pod set to maximize the N.  When pods start setting, N is moved from the root nodules to the leaves and eventually in to the pea.  (I have to learn more).

??-- can we mow or crush, setting back the podding, allowing the WP to continue building N?

??-- will we need to seed into this mat to extend the cover crop through the winter?

Fields Using Two Different Farming Systems

While walking our winter pea field and observing what was going on around me, I saw this site and thought, --there is a lesson here!  The pic shows two fields that have been farmed very differently.
      The field in the upper portion of the picture has been direct seeded for 20+ years.  The last three years it has been in a ULD system.  Roundup has been used extensively on the property over the years, along with a Valor application in the fall of a fallow year.  Problem weeds are few and far between, even in a low moisture, high temperature year like 2015.  Both of these fields were in spring wheat.  The upper field is currently seeded to Austrian Winter Peas.  They were dormant seeded in late November and are looking good.
        The field in the lower portion of the picture has been conventionally tilled it's entire life, using very little Roundup, and no Valor in the fallow year.  The field has a long history of a wheat/fallow rotation with an occasional spring barley/wheat crop thrown in.  This field has a heavy infestation of Russian Thistle and cheatgrass that has set seed.  It will be tilled, and a larger seed bank will be available to grow in future years.
        Reducing tillage reduces weed competition, and promotes better soil structure.  Both of these "pluses" save water for crop use.  It is a very difficult concept for many seasoned farmers to get their mind around.  The rapid reduction in our weed competition was a surprise to us as we moved from high disturbance no-till, to ULD (ultra low disturbance) no-till.

REDUCED WEED PRESSURE

[Update: 5/24/15]  We have recently sprayed our CF and DNS.  We have so few weeds in these fields that  it is difficult to justify the cost of chemical, but it is to soon to cut these applications.  Our agronomist advised against application to the CF, but we couldn't leave the scattered single Downy Brome plants.  We put out one short load doing the draws and bordering the CRP.
          The DNS has a light infestation of Downy Brome (the bane of our small grains and fallow rotation), and plants from the failed winter canola crop. We hit the crop with a fungicide, broadleaf, and grass herbicide.
     When I started direct seeding, years ago, one worry I had, was --chaff rows left by the combine.   Combines of any make will drop grain, and in areas, a lot of grain.  Our combine is no different then anyone else's.    Rains fall, seed germinates, and fields green up, but over the years ours have consistently shown less  than most fields.  Since 2012 when we bought the stripper head and changed from high disturbance direct seeding to ultra low disturbance direct seeding I have noticed that we have further reduced the weed pressure in our fields.
    We have some theories but no validated research to support the claims.
           ----Leaving the seed bank on the surface hastens its destruction over planting it!  For a long time I have felt that the elements (heat, cold, rain, wind, sun) would decompose seed if it were not buried.  There is a lot of research stating the number of years that various seeds can remain viable in the ground.
           ---Seed laying on a blanket of residue germinates, dries, and dies!  We think this occurs, even on bare soil.  Many seeds on the surface will take up moisture and dry and die before they can get a root anchored to sustain them.  It appears that the thicker the residue layer the better.
           ---There are a lot of critters (granivores) skittering along the ground surface (birds, invertebrates, mammals) that eat seed.  The tall stubble may be protection for these granivores.
     The purpose of our direct seeding from the start was the lure of saving moisture for use by our crops as mentioned in other posts (label--Moisture).  As we have progressed toward that goal, the reduction of weed pressure is a welcome side benefit.
     Where do we go from here?  With the adoption of the stripper head, and a ULD system in the form of the CrossSlot drill, we have reached a wall (in our thinking).  We have been very successful to this point.  What further can we do to improve moisture saving and weed reduction techniques.  COVER CROPS????

IMPORTANCE OF FALL CHEMICAL TREATMENT

         I recently spent a couple of days participating in tours designed for growers sponsored by private and public entities.  Of all the things that I saw and heard, the following was the most striking.  I'll be interested in the harvest data on this plot of spring wheat.  We all have experienced the anxiety of putting out chemical on ground that looks bare of anything growing.
         This pic demonstrates the importance of a fall chemical application when your intention is to plant a spring crop.  In this case the crop is a spring cereal.  It is a little difficult to visualize, but look at the pant line on the researcher.  The right side is about knee high.  The left side is about mid thigh.  There were no specifics given to compare the the two sides; however, the right side of the plot looked stunted, and thinner compared to the left side.   If the right side had been a field, the grower may not notice there being a problem.  Standing alone, the right side doesn't look that bad, maybe a little thin. The only difference in the treatment of this plot was that the right side was missed when the fall application of glyphosate was applied.  The researcher stated that there was very little material growing on the plot last fall.  Each side of the plot had it's spring application of glyphosate three weeks prior to seeding.  The entire plot was seeded at the same time, and all subsequent operations were done consistent across the entire plot.  The first indication that something was different was the delay in crop emergence on the right side.  Rhizoctonia was discovered to be the culprit.  The green bridge effect raises it's ugly head even when there doesn't appear to be any green.

So the lesson is:  DON'T MISS THE FALL APPLICATION OF GLYPHOSATE --- even though it appears there is nothing for glyphosate to act on.

WEEDS & CRP

  [update 7/21/14]:-- It's most unfortunate that I did not scout our fields last fall.  Some of our CRP fields have significant amount of Delmation Toadflax that did not get treated until this summer.  Last year we had a young man scout and treat these fields, but there was too much for him to treat using Husky and Tordon.  There is too much to treat with any aggressive chemistry now.   It would limit our crop selection for the fall of 2015 or spring of 2016.  I have just treated these fields with Range Star (2-4D + Banvel) and two surfactants (WetCit + M90).  I'll update later on the effectiveness of this treatment and whether WetCit cut through the wax.
      This spring we put spring barley as the first crop on a CRP field.  All of the grasses were dead, but the field has a heavy infestation of Rush Skeleton Weed.  We have treated this aggressively with applications of Rt and 2-4D.  Timing is everything with this weed.  We have successfully put the hurt on it while in the rosette stage, but little happens once it bolts.  We'll harvest this crop within three weeks.  I'm thinking that we may want to mow this field soon following harvest to stop any new seed development.  Rush S. is one that you do not want to do any type of cultivation on as that drags roots and promotes new starts.  Tours that I have been on clearly showed where new patches sprang up from the weeder dragging roots.  Most perennials have that potential; however, Rush S. takes full advantage of roots being dragged across the field. 
 Recently I had the good fortune of being asked by a family wishing to put CRP ground back into production, to express my thoughts and interest.  Since we will be taking significant acreage out of CRP ourselves in a couple of years, this was an opportunity to give thought to what is currently growing in the field, and how we should proceed for a cropping scenario.  We have two years to prepare.  This family had 1-4 months to prepare.  If, when evaluating a field, you find a difficult weed scenario, the more time you have to address the problem the better.
     In this families case, the field generally had a good stand and mixture of grasses that presented no difficulty to remove.  The weed spectrum included the usual annual broadleaves and grassy weeds along with a significant amount of Canadian Thistle.  These don't create any particular difficulty when going into a cash crop.  There is adequate chemistry available for successful Direct Seeding that will give good control before planting, as well as in-crop control.  The trick is to chose chemistry that does not limit your choice of cultivar for your cash crop.   In this families case, what was disappointing was to find a high infestation of Delmation Toadflax .  My guestimate is that 80% of the field is contaminated.  There are a number of densely populated patches, and single plant scatter throughout the remainder.  I spent a lot of time talking to people, looking up reports, and surfing the web for success stories on controling this noxious weed.  There was no quick and easy formula that I could find.  Whether you chemical'd or cultivated the field, it was going to have to done with persistence and with repeated operations for a lengthy period of time.  When established, the Toadflax plant has an extensive root system.  It is a prolific seed producer, and the seed will remain viable in the soil for 10 years.  (This tells me not to plant this seed through soil disturbance.  Leave it on the surface where weather and critters can attack it.)  The leaf structure includes a thick waxy coating that is difficult to penetrate with chemistry. (This tells me that a contact chemical will need a very good surfactant and probably used at a higher than normal rate.)
      When I synthesize all this material down for a management plan, I conclude that Delmation Toadflax  is no different than any other noxious perennial weed.  You have to stop the seed development and deplete the root reserves to remove the problem.  Timing is critical to reach your goal for the particular type of chemistry you are using.  Research supports the best timing for impacting the root system is in the fall with a systemic chemistry.  Antidotal statements indicate that most of the common chemistry we use for weed control in our crops will have an impact on Delmation Toadflax seed development when timed properly.  Severe damage to the seed stalk at the start of bloom either mechanically or chemically will stop seed production and help draw down root reserves as it attempts to recover.  Any management plan to remove this noxious weed from the field will include years of hand roguing your cash crop.
       I don't consider cultivation as an option.  It makes no sense to me to destroy all the gains in soil health made over the years in CRP, --- as well as put 10-25 years of seed in a "soil" bank, and make annual withdrawals for the next 10 years.  The seed will degrade much faster on the soil surface through weather and fauna.