| Grids Don't Fit |
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| Grids Don't Fit |
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The following series of CEC (Productivity) maps begins with a 52 acre map produced though the Conventional Grid Sampling Density of one soil sample taken every two and a half acres (1 sample every 2 1/2 acres), the second presents that same field --but with four times the detail--, the third presents a third version of the map --with sixteen times the detail--, and lastly a fourth map is presented with sixty four times the detail of the original Conventional Grid Sampling map. The highest density grid-sampled field is then compared to the standard sampling by the Soil DoctorŽ system. (All from the same 52 acre field in Jewett, IL).
In this study, we used high resolution TruVue (TM) data, and began by
resampling it at today's standard grid sampling rate to clearly
demonstrate what you miss when you limit yourself to a
low-resolution approach.
In interpreting each of these soil CEC maps, please refer to the
legend below to correctly interpret the colors designating CEC
levels.
Note that a value of 175
is a CEC of
17.5.
Considering the fact that plants can't pick
themselves up and walk over to where the better soils or the
higher nutrient supply are (like livestock can and do), . . .
See for yourself how using high resolution details to guide
applications will make a difference to the productivity of your
crop. It makes no sense to endorse "Precision"
Agriculture or "Precision" Farming and then
settle for fuzzy picture assessments of your soil's ---highly
variable-- productive potential.
NOTE: Soil DoctorŽ Applicators respond to Variability at a
much higher frequency than once every 0.039 acre (64 times
the frequency of conventional precision methods). Soil DoctorŽ
Applicators respond to changing soil conditions five times a
second, as the unit travels through the field, simultaneously
examining the soil.
The Sensor itself examines soil conditions at twenty-five times a second, while the System averages these samples --five at a time, five times a second-- for real-time use by the Applicator. Typical Soil DoctorŽ soil sampling density is equivalent to 7,250 soil samples per acre, where each soil sample is one cubic yard of soil.
With a Soil Doctor applicator, your
productive soils are clearly identified and are not subject to
the cost limitations imposed by conventional grid sampling. Why
use a yield monitor, take 1500 yield samples per acre, and then
try to understand all that yield data based on only one soil
datum every 2.5 acres?
With Soil Doctor technology, you get TruVue high resolution, accurate soil definition that is not subject to errors from interpolation and geostatistical krigging.
Look over all of these maps. The
"red" areas are the best (highest CEC/highest Organic
Matter) areas. Ask yourself if you can be satisfied with any
method of classifying variability that it can be far off the mark
and miss all of the "red" areas, or imply that the best
areas are in places where they are not..
CTI does recommend conventional soil sampling
for assessing general soil levels, not as the preferred method
for determining site-specific, foot-to-foot, application rates.
Reference Soil Sampling (not an expensive, high density Grid Sampling program) is necessary for general field diagnostics, like when you want to verify that soils High in nitrate last year really are Depleted of nitrate this year, when you begin farming "new" property and suspect it to be exhausted of all it's P&K, or when you want fine calibration of the organic matter feature for spraying. Carefully coordinated laboratory analysis information can help you set your Soil DoctorŽ System to high accuracy, for extremly site-specific herbicide delivery.
COMPARING GRIDS AND TRUVUE(TM) SURVEYS
The button above provides a branch to a practical study guide for comparing high fidelity TruVue soil surveys with conventional grid sample data. If you haven't done so already, you will need the Windows Media Player first to access this Presentation.
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Several CTI customers who traditionally relied upon their fertilizer dealers as consultants recently chose independent consultants to soil sample their fields. Across the board, the independents consultants found considerably higher levels of macro-nutrients than did those dealers. Sometimes they found as much as fifteen years worth of stockpiled soil nutrients, negating the need altogether for applying any P or K.
Excessively high levels can contribute to reduced crop yield, and, in some cases, seventy+ year old veteran farmers had been warning that their yields of thirty years ago --on those same fields-- were much higher than recent years' yields. So do take conventional soil samples, or have a reputable consultant do so for you.
Remember reading the magazine reported results of precision farming studies that "There is no Correlation between "Soil Fertility" and Crop Production"? It's a lot like reading that "Plant population does not correlate to crop production." (See Asgrow yield.) Well, when your soil P&K fertility levels are maxed out, putting more P & K where you have less and less P & K where you have more, Simply can't produce a better crop. The crop cannot respond to fertility added beyond a peak soil level. Adding "maintenance" fertilizer can increase your stockpiled investment in the land, but it can't produce an economic return. Every input has its limits, where any additional amount is harmful, driving yields down rather than up.
To you, they could be just
pretty pictures;
But, to your crop, it's where it feeds.
The greater the push for Efficiency, the more Precision (The Soil DoctorŽ System) is needed. So, don't settle for only one sample in 2.5 acres. Get true foot-to-foot accuracy and the clear resolution of TruVue (TM) maps.
