All DS drills can seed and grow an excellent crop and improve soil health. Farming too efficiently use the moisture we are provided, and the pace too improving soil health is the difference I see between high and low disturbance drill designs.
High disturbance drills (the term I use for all hoe, double disc, and some single disc openers) all share a similar problem, --they move or disrupt too much soil which exposes the soil surface. As a result they break infiltration channels, they accelerate decomposition of cover, they plant unwanted seed, and they damage the soil food web if any is present. There are places in our field where even the CrossSlot fits into the high disturbance category, --on steep slopes where side pressure causes a wider slot, and where we turn.
I distinguish between DS drills by the amount of soil surface they disturb. They range from disrupting nearly the entire surface down to a narrow slot of <1.5 inches. I would say that most hoe drills fall in the high disturbance category, and most single disc drills would fall in the low disturbance category and the CrossSlot in the ultra-low disturbance category. Others may have their own scale. By the numbers:
High disturbance drills: Their configuration disrupts a large percentage (>70%) of the soil surface and most or all of the surface residue.
Low disturbance drills: Their configuration disrupts (<30%) of the soil surface and about 60% of the residue.
Ultra-low disturbance drills: Their configuration disrupts (<15%) of the soil surface and maybe 40% of the residue.
Whether the numbers accurately describe the drill type performance is not the point here. What is important is that they represent the concept that the more soil and residue that is disturbed, the more moisture you lose from evaporation, the less moisture your field can absorb from later rains because of disrupted channels, the more biological communities in the soil you disrupt which effects plant food production, and the more unwanted seed that will be planted grow and compete with the crop.
To maximize moisture retention and absorption, you will want to minimize disturbance of the soil surface, grow and maintain the maximum amount of residue possible, and leave it as tall as possible in the absence of a growing crop. (see other posts for the reasoning behind this statement). It's my belief as well that this statement is valid for all rainfall regions whether 7" or 70".
Wednesday, June 28, 2017
Monday, June 26, 2017
WHY WE HAVE GONE ULD
A recent post referenced to why our operation has gone ULD (ultra-low disturbance) direct seed system. I didn't elaborate on this because, although the two mentioned subjects of that post connected in my mind, the Richard Mulvaney article was my main interest. On reflection I've decided that our reasons for going ULD should be posted.
On our quest to improve our soil we have encountered many obstacles, mistakes, disappointments, questions on how to proceed, and yet, having enough success to continue the quest.
Soil EROSION, and removing fallow from our rotation was the initial driving force. Any operation that reduces soil disturbance compared to what we are doing with conventional tillage will have a positive impact on the soil. Direct seeding is a big jump in reducing soil disturbance. Past history of direct seeding shows that the soil surface is left, more or less in a state of nakedness, and channeled. Nakedness is correctable; however, I can't envision how you can 'drill' a crop and not channel, whether it be double disc, hoe, or a single disc, including the CrossSlot drill. In the Palouse channeling can be a serious erosion issue if not considered when drilling the field.
As we progressed, saving MOISTURE became the driving force. Although we still have some erosion at times it was mostly contained, --at least visually. As time passed and information gathered it became clear that we needed good soil structure, more soil organic matter, and more cover on the surface, to maximize the retention of moisture. WSU-OSU research back in the 70-80's indicated moisture was used in four ways, -----1% to deep percolation, 4% to runoff, 12% to plant transpiration, 83% lost through evaporation off the soil surface. Research is clear that a soil profile with a cool surface temperature and a calm surface, retains more moisture compared to a hot surface with air moving across it. The more we reduce soil disturbance, the more residue we keep on the surface, and the calmer we can keep the air at the surface the better our soil moisture will be. Taking these parameters to the maximum create a serious challenge for drill design.
In 2012 we moved to ULD by buying a stripper header and hiring our seeding done by a CrossSlot drill. Now, our ULD direct seed system consists of a Shelbourne stripper header, GVM 90' suspended boom self propelled sprayer and the CrossSlot drill.
Shelbourne stripper head: --maximizes vertical intercept of snow and wind. The taller the stubble the more snow catch (very effective in the winter of 2016-7), and the taller the stubble the calmer the air at the soil surface. (measurements are showing that to be very effective also. The only down side is that we can't harvest every crop type with this header.)
GVM 90' suspended boom self propelled sprayer: --it's value is in reducing tracking in the field. It's very evident that tracks of any type promote weed emergence compared to the untracked portions in a field. We regularly see this in our fallow fields.
CrossSlot drill: --the machine that makes ULD possible. The header and sprayer are the supporting cast. When we were evaluating drill technologies, and our operation, trying to match a drill to the specifications and limitations that we faced, the CrossSlot opener was the obvious choice. The CrossSlot has the ability through its depth and pressure related sensing capability to place seed in good earth at the assigned depth while passing through complex soil types and textures, residue types and amounts whether standing or laying down, without stopping for adjustments. It's a remarkable technology, and we have learned not to move unless it is all working. Until the residue became too heavy to manage, our other hoe or double disc drills, could start a good fall crop; however, we never had a very good producing spring crop because of voids left by hair pinning or clumps of residue that shed off the drill, or seed not being placed at the proper depth.
We are now set up to do ULD, and with the CrossSlot we are ready for the next stage which is building soil health. (which is becoming a whole new story)
On our quest to improve our soil we have encountered many obstacles, mistakes, disappointments, questions on how to proceed, and yet, having enough success to continue the quest.
Soil EROSION, and removing fallow from our rotation was the initial driving force. Any operation that reduces soil disturbance compared to what we are doing with conventional tillage will have a positive impact on the soil. Direct seeding is a big jump in reducing soil disturbance. Past history of direct seeding shows that the soil surface is left, more or less in a state of nakedness, and channeled. Nakedness is correctable; however, I can't envision how you can 'drill' a crop and not channel, whether it be double disc, hoe, or a single disc, including the CrossSlot drill. In the Palouse channeling can be a serious erosion issue if not considered when drilling the field.
As we progressed, saving MOISTURE became the driving force. Although we still have some erosion at times it was mostly contained, --at least visually. As time passed and information gathered it became clear that we needed good soil structure, more soil organic matter, and more cover on the surface, to maximize the retention of moisture. WSU-OSU research back in the 70-80's indicated moisture was used in four ways, -----1% to deep percolation, 4% to runoff, 12% to plant transpiration, 83% lost through evaporation off the soil surface. Research is clear that a soil profile with a cool surface temperature and a calm surface, retains more moisture compared to a hot surface with air moving across it. The more we reduce soil disturbance, the more residue we keep on the surface, and the calmer we can keep the air at the surface the better our soil moisture will be. Taking these parameters to the maximum create a serious challenge for drill design.
In 2012 we moved to ULD by buying a stripper header and hiring our seeding done by a CrossSlot drill. Now, our ULD direct seed system consists of a Shelbourne stripper header, GVM 90' suspended boom self propelled sprayer and the CrossSlot drill.
Shelbourne stripper head: --maximizes vertical intercept of snow and wind. The taller the stubble the more snow catch (very effective in the winter of 2016-7), and the taller the stubble the calmer the air at the soil surface. (measurements are showing that to be very effective also. The only down side is that we can't harvest every crop type with this header.)
GVM 90' suspended boom self propelled sprayer: --it's value is in reducing tracking in the field. It's very evident that tracks of any type promote weed emergence compared to the untracked portions in a field. We regularly see this in our fallow fields.
CrossSlot drill: --the machine that makes ULD possible. The header and sprayer are the supporting cast. When we were evaluating drill technologies, and our operation, trying to match a drill to the specifications and limitations that we faced, the CrossSlot opener was the obvious choice. The CrossSlot has the ability through its depth and pressure related sensing capability to place seed in good earth at the assigned depth while passing through complex soil types and textures, residue types and amounts whether standing or laying down, without stopping for adjustments. It's a remarkable technology, and we have learned not to move unless it is all working. Until the residue became too heavy to manage, our other hoe or double disc drills, could start a good fall crop; however, we never had a very good producing spring crop because of voids left by hair pinning or clumps of residue that shed off the drill, or seed not being placed at the proper depth.
We are now set up to do ULD, and with the CrossSlot we are ready for the next stage which is building soil health. (which is becoming a whole new story)
Thursday, June 22, 2017
N is burning the Carbon Pool
Two recent events have triggered this post. I recently gave a presentation on why our operation has gone to a ULDDS (ultra-low disturbance direct seed) system along with sharing our cover crop experience (as limited as it is) to a group of NRCS trainee's from across eastern Washington, and, an article that came out in the July issue of NO-TILL Farmer, titled "Excessive 'N' Application Burning the Carbon Pool (vol. 46, #7).
The first event had fertility on their minds as part of the general discussion on soil health. the article authored by Richard Mulvaney, a University of Illinois fertility specialist, had specifics. His position is based on mining documents on fertility, and data sets, going back 100 years. His comments helped me to link pieces of a foggy puzzle about crop fertility and how it will react on soil health. His recommendations are going to be a challenge for us to address. The following is what I found engaging: (most will be paraphrased)
---soil is an important source of N.
---applying N does not build organic matter.
---you can not bank N by adding N. Soil microbes use it to burn the carbon they find in residues and soil organic matter. This results in less C and less SOM. (my thought: --this may be why we struggle to move SOM above 3%)
---"You can never decouple carbon and N --not on this Earth....". Microbes use N to make enzymes so they can burn the carbon that supplies their energy. Every enzyme has N.
---crop rotation is best. Corn yields are better in rotation than with continuous corn, and done with much lower fertilizer inputs. The data tells me that fertilizer cannot replace rotation for highest yields. (my thoughts: Follows Beck's principal, rotation-rotation-rotation)
---Mulvaney's best short-term option for growers would be to increase efficiency by putting more of the fertilizer N, "into the crop" when it is needed. --by:
---Use tests to determine what the soil can provide.
---Don't apply NH3 in the fall. There is no crop (corn in this case), and there is a lot of microbes that will use the N. (my thinking: --our fall wheat does not need all the N that we customarily place with it.)
---Sidedress N to synchronize fertilization with crops N demand. Ideally, shift from ammonia to nitrate fertilizers despite the greater risk of N loss through leaching and denitrification. Mulvaney & colleagues base this idea on scientific evidence that plants have an edge in taking up nitrates, whereas microbes are better competitors for ammonium.
---the 1947 book, The Soil and Health by Sir Albert Howard, claims that there will never be sustainable agriculture until animals are put back on the land. It's a cycle. Do we need to rethink the big picture. (my thought: --several people heavy into covers are going this route)
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