Considerations for Transitioning to Diverse Cropping
and Direct Seed Systems -- Grower Perspective

 

Chris Laney
Sprague, WA

Introduction

The following ideas and suggestions are meant to help those considering adopting direct seeding technology or at least experimenting in that direction. Jumping in 'cold turkey,’ is, of course, an option, and it has been done, sometimes even successfully. A more prudent approach, however, would be to attempt to merge smoothly form one’s current conservation or conventional farming practices into the no-till arena.

Premises

No-till has been locally customized all over the world to fit climate, topography, growing seasons and other agronomic factors. In some places it simply means changing to direct seeding with no other change in the customary cropping pattern, while other places it involves adding new crops to the rotation and other substantial changes including switching from fall seeded varieties to spring varieties. For our discussion today, we are going to assume we’re adopting the Cadillac version, that is, Annual Cropping, Intense Rotation, and Direct Seeding, or ACIRDS, which would include a broadleaf in the rotation. I leave it to you to weed out those suggestions that do not pertain to simpler formats.

Time Frame

You can expect two approximately 5 year long time frames involved with adopting no-till. One precedes the initiation of direct seeding and the other starts at the point of initiation and covers that time it take no-till to mollify your soils to where no-till’s full beneficial effects are realized. The pre-No-Till period may be shorter or longer than 5 years depending on your soil type and previous chemical use. The post adoption period will not likely be any shorter than 5 years and could be much longer depending on the rate of adoption and the growing conditions for accumulating a residue ‘mat’ (sometimes referred to as "duff"). This 5 year transition period is also the most dangerous for producers. Let’s look at a transparency to better visualize why that it…

Soil Mollification Graphic

The left hand side of the graphic below illustrates a vertical cross-section of conventional summer fallow: A top layer of dust mulch acts as an insulating barrier protecting seed zone moisture and deeper moisture from the forces of capillary action that would otherwise continually pull moisture to the surface and evaporate it into the atmosphere.

Moving to the right, we see the abrupt change to no-till, where the dust mulch layer is immediately discontinued. Its insulative substitute is a layer of residue; however, during the start up years, the thickness of this residue mat does not provide the insulative equivalent of the dust mulch. Depending on whether high or low residue crops are grown, it could take a few to several years to obtain a mat thick enough to protect seed zone moisture and absorb hard rain storms.

During this adoption period the former tillage zone is gradually mellowing after years of being pulverized by tillage and packed by traffic. The triangular area in the graph represents this progression. Obviously, the early years of adoption present the largest risk wherein there is little absorptive cover and surface insulation at the same time the tillage zone has barely begun to increasing in porosity, organic matter, tilth and water holding capacity

Soil Mollification Graphic

 

Pre-Adoptive Measures

Undoubtedly a common impediment a dryland grains producer faces in starting into an Intense Rotation no-till regime is the persistence of long-term herbicide residuals. S.U.s, in particular, can forestall the introduction of broadleaf crops into the rotation by three to five years and sometimes more if one’s soils have a high clay content. So beginning at five years out, here are some steps to consider:

-- You will need to discontinue the use of intermediate and long-term residual herbicides. If you have acquired more land recently, research the chemicals used by the previous operator. If you’re still not sure, then grow some bio-assay plots using susceptible crops. Locate them on your predominate soil type, but also have a site on a clay knob. Remember, the chemical residual knife cuts both ways: You will need to know if new crops to be introduced are susceptible to historical and currently used chemicals, and you will also need to research the common chemicals to be used on your new crops to be sure they can rotate safely back through your grains. Your local Ag-chemical dealer can be of invaluable service in this regard.

-- Also, you may want to immediately intensify your soil testing. Not only in the number of tests you ordinarily have taken, but also in the amount of information you request. Knowing your soil’s pH, per cent of organic matter and cation exchange rate, for instance, will not only give you a pre No-till baseline from which you can track changes in your soils’ health status, it will also be helpful in selecting the best suited new crops in your expanded rotation. Along this same line of thinking, you will want to know the expected number of Growing Degree Days for your farm and the number of Frost Free Days beginning with the last killing frost in the spring and running through the first killing frost in the fall. Knowing this data will likely automatically eliminate some alternative crop choices and for others, such as corn, it is basis for selecting the correct seed variety for your location.

--As your sprayer could effectively replace your entire line of tillage equipment, you may also want to have your water supply tested. Your water’s pH, hardness (calcium) and mineral levels can all affect the proficiency of your chemicals. A needed buffering agent could provide big returns. Keep in mind, that under a fully implemented direct seeding, annual cropping system your sprayer could be going over every acre of your farm an average of three times a year.

-- Another pre-adoption element that cannot be started too soon is bringing your landlord and banker up to date on your intentions. You might want to tell your wife sometime before you start, also. These important partners need to know your strategies and timetable in order to understand yours and their exposure to risk.

Equipment

If you are looking at going No-till, but residual chemicals in your soil, financial risk or some other reason make it several years away, some preliminary steps can still be implemented now that are relatively low cost and do not irreversibly commit you to No-till, as they are very compatible to conservation tillage also:

-- Equip all combines with full-header width chaff/straw spreaders. The even distribution of residue is essential for attaining successful chemical weed control. But even if you stay with tillage weed control, the even distribution of straw and chaff will make seedbed preparation easier and more uniform.

-- Upgrade the accuracy and reliability of your sprayer. The sprayer, as indicated earlier, is rapidly becoming the most critically important piece of machinery on the farm under either method of farming. The increased sophistication of chemicals coming on the market will only make this more so. It almost goes without saying, if you go No-till you will need your own sprayer. The timing and frequency of spraying operations in a multi-crop rotation will be too critical for you to be sitting on a waiting list.

-- Repairs and maintenance should be re-prioritized. Give highest attention to machinery that is used under both farming methods, such as trucks, tractors, combine and sprayer. Conversely, tillage implements that may soon be phased out, or at least seeing fewer acres each year, should have the minimum amount of investment possible.

-- Any new machinery purchases should also be done looking well down the road. A new or newer tractor, for instance, should possess adequate speed, power and hydraulic capabilities to operate a no-till drill. Considerations on choosing a particular combine model might now include its capacity for handling and processing straw and the speed and ease with which it can be adjusted or cleaned between different crops. Even the type of truck you need may change if you will have to deliver a higher valued/specialized crop to a more distant delivery point.

High Disturbance or Low Disturbance?

Up to this point in the process everything has been preparatory to no-tilling. When you decide to actually begin direct seeding your biggest decision is presented: Do I go with a low disturbance system or a high disturbance system?

No-till has a whole dictionary of its own. When an article refers to "low disturbance" technology it usually means a drill using an angle disc opener. The two most popular are made by John Deere and Flexi-Coil. Only a narrow kerf of soil is disturbed under this system, thus weed seeds between the seed rows are not disrupted and thus don’t germinate. Drawbacks include a relatively cool seed bed, which can result in slower germination. Fertilizer placement may also require an additional tool bar and coulters if a one-pass approach is desired.

High disturbance systems usually employ a hoe-type opener on a shank assembly. Fertilizer is placed through the same specialized point. Because the point is wider than a disc, the bare soil left behind it warms faster leading to faster germination. Likewise, more weeds are also germinated as more soil is loosened and stirred. Other drawbacks include higher power requirements (approximately 7 hp per shank) and greater difficulty in controlling seeding depth, especially for small seeded oilseed crops.

Both systems have their supporters and detractors. As do several types of systems in between such as the Yielder and its double disk openers, but also relatively high disturbance.

Conclusion

This presentation hopefully has been of help to anyone interested in transitioning toward direct seeding a diversified rotation. We have looked at preliminary steps necessary to complete before you are at a point where you are able to no-till. We have also addressed what to expect of your soils after you have stopped tilling. Each of you will eventually have to customize no-till to your specific farm, but that will never happen in your initial trial falls. Give this system a fair chance—place it on good ground and only commit as many acres to it as you are willing to stay with for a minimum of 5-6 years.


 

 

DspropCL.doc