Soil Preparation and Analysis
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Subject: How To Live With Soil Test Reports & AG's
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Date Posted
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Tremor |
Ctpumpkin@optonline.net
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This little diatribe isn't intended to explain a soil test report to you. Rather it is intended to help growers understand why they don't understand the results.
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10/4/2004 11:38:19 AM
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Tremor |
Ctpumpkin@optonline.net
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Soils vary. Plowing & tilling fails to move or blend differing soils to a statistically significant degree. Animals (and growers!) pee, poop & die on dirt. Insects & Plants die & decay too. Some weeds are known to fix an uneven amount of elements, die, decay & ultimately influence fertility some years later in a spot of several square feet. We spill & misapply stuff regardless how good we think we are.
Manures vary by the animal that does the eating & what they are fed.
Who hasn’t spread granular fertilizer by hand? What is the fate of the prills that land on the top of a small mound of soil? They roll off & collect in the lowest points that surround. Rounder fertilizer prills are known to experience “ballistic particle segregation” on the ground. Irregular shaped prills experience the same thing during flight where their shape affects the trajectory & they land on the ground after separating from a blended continuum. Different bulk blended raw materials have different bulk densities as if this subject isn’t already confusing enough. Poor raw materials may separate in the bag during transportation.
Liquid solutions of fertilizers may be poorly suspended to save manufacturing costs. Certain soluble powders fail to completely dissolve especially if the mill that is used to prepare them is starting to wear out. High Phosphorus blends are especially prone to this issue.
And probably no one among us is using modern GPS assisted computer controlled application equipment that is tied to a soil test grid program for in-field custom fertility applications.
For a field agronomist to collect soil samples, he must walk a pattern making samples of the field in the depth of the rhizosphere. These are placed in a clean bucket & thoroughly mixed together so as to blend the hot spots with the cool ones. Which ones to segregate as “hot spots”? You probably know better than him based on your
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10/4/2004 11:38:57 AM
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Tremor |
Ctpumpkin@optonline.net
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As growers, if we have made inaccurate amendments or tilled/plowed an area a little deeper than the rest & brought up subsoil, then we need to either test that area separately or accept the fact the results aren't going to be entirely consistent.
Probably the best bet for us is to treat & test each planting mound & its main vine landing area as a separate patch. The outer edges of the secondary vines don’t root very aggressively. So maybe we should limit the collection area to the 10’ diameter around the crown & the 12’ x 14’ triangle the main will land in.
The next most important task for us is to find a truly competent lab that is easy to work with & the agronomist has a clue what we are trying to do. This is no small task in suburbia.
There are NO STANDARDS for growing competition Atlantic Giants other than those opinions that have been expressed here & at other better websites & a handful of book like Don’s. Even these opinions are often in conflict with one another.
“New Agronomy” says to not lose sleep over the Base saturation Cation Percentages. Instead we seek to meet or exceed all of the minimum nutrient values to support realistic crop yield goals. But those minimums are based on sound financial principals that fly in the face of competitive growing where the crop yield goals are ridiculous.
The “old schoolers” tend to get hung up on the percentages often at the expense of watching the minimums fall below critical thresholds for optimum growth at some point in the growth event (season).
Personally I like to live in the middle & never cross without looking both ways. We can design fertility programs that speak to both needs. But it is much harder to do this way. No soil scientist is going to make unusually heavy fertilizer recommendations. Reputations are even more expensive than failed crops.
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10/4/2004 11:39:21 AM
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Tremor |
Ctpumpkin@optonline.net
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The main thing is to recognize how quickly Atlantic Giants draft down the “soil bank” in-season. Constant reapplication may only mask what is happening to our soils, but said foliars can keep the legs from falling out beneath us. Just make sure the dynamics of the soil are known before prescribing to a foliar program. It isn’t hard to cross the line on good soils that have ample reserves. Splits anyone?
Cation Exchange Capacity greatly influences how our soils respond to what we do & apply. This is probably the most daunting subject for even the heaviest hitters. As such, I think many Hitters admit to turning a blind eye to their soil reports & instead call on the advice of a local soil scientist at the testing lab they use.
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10/4/2004 11:39:39 AM
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Tremor |
Ctpumpkin@optonline.net
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We could get into bacteria & the temperatures effect on them. We could touch base on bacterial suppressants & stimulants & inoculants. But that’s another story for another day.
This is the best advice I can give to anyone. Network & make friends. Find a good local soil lab. Meet with their soil scientist. Work with that person or a qualified member if their staff exclusively. It can take years for the “Heavies” to develop a good understand of modern fertility practices & how they apply to what we do. Some growers are lucky enough to live in an area where a group of tenured growers & their support staff already exist. Think Hillsboro County, New Hampshire.
George Hamilton (of the Hillsboro Soils lab) often sees his advice go unheeded because he is too conservative for the desired yield of his areas growers.
This year in several area patches, we did spring, summer & fall soil tests. In my own patch (same soil) I confirmed the results with in-season tissue analysis. What we do works as long as the other stupid Newbie mistakes that I made (like pollinating everything & leaving them on too long) don’t end the season before Oct 2nd. LOL
Even given perfect soil management practices our plants are still limited to the environments they grow in, the pests they encounter, the hail that falls, the mice that bury & dig, the neighbor spreader full of Weed & Feed, the trees & structures that block light, the growers that fall asleep at the switch after pulling an all-nighter, & the genetic potential of the seeds.
Isn’t everything always much clearer in the rearview mirror?
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10/4/2004 11:39:57 AM
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Stan |
Puyallup, WA
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Just sent my soil off to the lab for analysis today!
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10/5/2004 11:42:50 PM
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Total Posts: 6 |
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