Residue protects the field

This post has sat as a draft for more than a month.  It has enough information that I decided to finish and publish rather than delete.  It's been a unique year.  I could visually compare--(heavy residue vs no residue, contour seeding vs vertical seeding)

     In February I scouted our winter wheat fields mostly for erosion, and comparing drilling patterns and ground cover.  It was consistent across the region, --on our fields as well as the neighbors.  This year, all of our winter wheat is planted on either, spring or winter pea stubble.  One field has full ground cover and the other has a lot of dirt showing.   There are so many potential variables(slope, aspect, micro-climates, etc), that frequently it is difficult to see a consistent pattern.  This year was different because of the type of winter.  Most of the region received about the same weather over a long period of time.  The whole region experienced abnormally high rain and snow fall this winter. Erosion followed the book where direct seeding showed significantly less erosion than cultivated fields.   Also, the more  surface cover, the less the erosion in direct seeded fields.  

This pic shows early drying of an eroded field.  The "sponge" top soil has been eroded off the ridges and well down the slope.  The dark areas are still showing surface moisture that hasn't evaporated off yet.  These areas are benefiting from water moving from the low water holding capacity areas of the field along with the fact these areas probably have more OM (sponge layer).  There is no surface protection on this field.  

This picture shows two different fields.  The typical cultivated field is at the top the picture,  and a direct seeded field at the bottom.  The aspect is north and the pic shows where deep snow drifts lingered in both fields.  The field at the top had no surface cover other than a nice stand of small wheat.  The field in the lower part of the picture had enough residue (wheat and pea) that very little dirt could be seen and was seeded with a cross-slot drill.  The lower field did not have visible soil erosion, but it did lose water.

This picture shows the amount and type of residue that is protecting the soil surface of the direct seeded field pictured above.  This is a combination of winter wheat and spring pea stubble.  This year, our heavy residue fields are showing rodent damage where the drill left piles.  It appears that those areas are recovering.  We have seen this once in the past where piles of loose straw sheltered rodents under the snow.

This picture shows a winter wheat field on winter pea ground.  This field had two years of low residue and seeded late to winter wheat.  The field history was (chem fallow seeded to winter canola that failed, then seeded to spring wheat, then dormant seeded to winter peas, and now seeded very late, do to the fall rains, to winter wheat). It looks like there is no crop, but the crop  has come through fine.  Even though we use a ULD system and have direct seeded for 20+ years,  if there is little or no cover on the ground there will be visual erosion.  Seeding vertical down the slope accentuates the issue. This field also shows the value of seeding on the contour rather than vertically.  The extreme left side of the picture shows the contrast between contoured and vertical seeding.  The contoured seeding had some soil movement, but you have to look closely to detect it.  Most of the field had some cover.  The corners with multiple tractor/drill passes (as shown above) were the most vulnerable areas.  This area has very light soils and regularly gets beat up with any field operation.