Conservation from different "No-Tills"

     Over time "No Till" has taken on different meanings for different people.  I'm hearing the term no-till linked with as many as three operations on a field.  Mostly the tools are identified as, drill, shank fertilizer applicator, harrow and/or packer.  Whether one or three pass, the ground is left in better condition than a conventional cultivation system, --HOWEVER, there is a significant difference in the potential soil health between 2-3pass "no-till", high disturbance no-till and ultra low disturbance no-till.   Conditions where water is allowed to move across the ground surface is erosive, regardless of residue volume or ground firmness, --it's only a matter of the degree of erosion.  Water flowing across the ground will contain particulates of dirt, pesticides, and fertilizer.  These in turn overload low areas of the field or go off site into the public domain.

      What can we do to minimize this loss?   -- Farm in a manner that least disturbs the ground surface.  Surface disturbance destroys the channels made by roots, worms, and other organisms that allow rapid movement of water into the soil profile.  Also, every operation creates some "fines" that are redeposited and seal spaces between soil particles.  Harrows are notorious for "fining up" the ground.

 --Every operation reduces the surface cover, and degrades the ability to intercept and dissipate the explosive energy of a rain drop.  Above is a  magnified pic of a raindrop impacting the ground surface with no intercepting residue.  This condition is very destructive to soil aggregates and seals the soil surface quickly.  There are a number of good online videos that show this happening.

     [Some old history] --  This story is to make the point that leaving channels undisturbed, uncovered, exposing them to the surface is very important for moisture intake.   In the 1970's, WSU experimented on ways to enhance rain moving into the soil profile.  One experiment consisted of using a baler frame, modified to stuff wheat residue into a slot.  Their experiments looked so promising that I kept an old baler to make the machine.  The machine was clever and simple.   The pickup and conveyer mechanism was left intact.   A deep ripper shank was located where the gearbox for the plunger would be, and a large wheel mechanism was mounted in the area of the bale chamber to pick off the residue coming from the opening that fed the bale chamber.   The wheel would push the residue into the slot left by the ripper shank filling the slot and leaving material at/above the ground surface.  The concept was proved do-able and was very successful.  With the slot open to the surface, rainfall was intercepted and fed into the soil profile.  The slots needed to be spaced so they would intercept the flowing water before noticeable erosion developed.  Depending on the steepness of the slope these slots could get fairly close, 5' to 20' intervals.  --THE RESIDUE IN THE SLOT concept ultimately failed because once the slots were covered from tillage operations they didn't work.    Without the slot being exposed to the surface, rainwater flowed right across the slot continuing down the slope as if it never existed.  The slots, in effect, had to be installed annually, and this proved too burdensome to be a viable conservation management practice.  

     The issue has not changed with time.  Any surface disturbance closes the natural channels made by decayed roots, worms and other organisms.  This in turn slows the movement of rainwater into the soil profile and promotes more surface water movement.  In my estimation, this is the reason we see better infiltration at 5 years than we do after one year of no-till.  Plants, worms and other burrowing organisms keep adding new channels over the years, where it takes only one pass of a farm tool to wipe them out.

     There are a lot of options available today for single pass no-till (direct seed) drills.  Everything from the maxi-disturbance (Anderson opener style), to the ultra low disturbance (CrossSlot opener style).

     I don't consider any two pass operation as no-till regardless of the drill type used.  Those operations will never move the needle from soil destruction to soil building in the environment of the Palouse.