Many naturally assume that "Increased Population" almost always automatically means "Increased Yield". Asgrow data indicates that it doesn't always happen that way, that is --unless you use Soil Doctor® Variable Rate Technology.

Additional Hybrid/seeding rate/yield performance experimentation was conducted on the Holsapple Farm (Clane soil) by Asgrow during 1996. Hybrid/Stand/Yield data is summarized below. All replicated test plots were sidedressed with George Holsapple's Anhydrous Soil Doctor® VR nitrogen applicator operated in the Nitrate and CEC sensing mode. Nominal plots were documented at 25,300 plants per acre and Increased stand plots were documented at 28,700 plants per acre.

Hybrid-------------------------------Nominal Stand-------------------Increased Stand
-----------------------------------25,300 plants per acre----------28,700 plants per acre.
RX843---------------------------------123 bu/acre-----------------------135 bu/acre--
RX771---------------------------------151 bu/acre-----------------------157 bu/acre--
XP7625--------------------------------148 bu/acre-----------------------163 bu/acre--
XP7805--------------------------------152 bu/acre-----------------------161 bu/acre--
P13335---------------------------------141 bu/acre-----------------------157 bu/acre--
XP6705--------------------------------140 bu/acre-----------------------161 bu/acre--
P13394---------------------------------151 bu/acre-----------------------152 bu/acre--
P13489---------------------------------131 bu/acre-----------------------154 bu/acre--
RX770---------------------------------107 bu/acre-----------------------144 bu/acre--
DK604---------------------------------114 bu/acre-----------------------136 bu/acre--
RX760---------------------------------131 bu/acre-----------------------152 bu/acre--
CA7770--------------------------------137 bu/acre-----------------------133 bu/acre--
RX790---------------------------------118 bu/acre-----------------------150 bu/acre--
P13525---------------------------------152 bu/acre-----------------------120 bu/acre--
DK618---------------------------------131 bu/acre-----------------------144 bu/acre--
RX801-----------------------------------93 bu/acre-----------------------136 bu/acre--
NK6800-------------------------------117 bu/acre------------------------152 bu/acre--
NK6822-------------------------------120 bu/acre------------------------160 bu/acre--
CA6997-------------------------------108 bu/acre------------------------128 bu/acre--
RX601---------------------------------140 bu/acre------------------------133 bu/acre--
DK626---------------------------------109 bu/acre------------------------118 bu/acre--
RX789---------------------------------110 bu/acre------------------------136 bu/acre--
RX701---------------------------------122 bu/acre------------------------140 bu/acre--
RX699---------------------------------108 bu/acre------------------------140 bu/acre--
RX510---------------------------------116 bu/acre------------------------117 bu/acre--
RX623---------------------------------113 bu/acre------------------------132 bu/acre--
RX620SR-------------------------------96 bu/acre------------------------118 bu/acre--

A Summary of participants and locations of the other test sites are shown at the Asgrow Web Site. That data states that Mr. Holsapple's N application rate was "Soil Doctor." The actual rate he applied was only 72 LBS N/acre.

As shown in the detailed Asgrow Hybrid Results above, over all varieties, an average Population Increase of 13.4% resulted in an average YIELD INCREASE of 13.6%, while using Soil Doctor® technology at Sidedress. In dramatic contrast however, in the five other tests --which used the same seed varieties, BUT

Although good results were achieved with the Soil Doctor® applicator at the population increase of 13.4%, the more modest population increase of 11.6% --without the Soil Doctor® applicator-- ALWAYS DECREASED YIELDS.

Even more remarkable however, the Soil Doctor-Treated hybrids received 0.5 LBS N/BU LESS (an average of only 0.92 LBS N/bushel or 72 LBS/Acre), while Non-Soil Doctor Treated hybrids received an average of 1.42 LBS N/bushel (and up to 1.7 LBS N/BU or 300 LBS/Acre).

Worth noting: The Asgrow data Proved that the Soil Doctor® System provided Adequate Nitrogen supply, foot-to-foot (even though, on-average, significantly less fertilizer was used) to support the Increased Populations, enabling a significant yield increase in 24 out of the 27 different varieties tested. Including the three cases where the yield was decreased-- the average increase in yield was proportional to the average plant population increase, as you might have expected from all test comparisons.

Each of the five other tests was conducted --using all the same hybrids-- on five other soils, within Illinois and Indiana.

Analogous to nutrient management (See Grid Soil Sampling), the Asgrow data proved that when you are farming at a "Maxed" population, a potentially stressful condition, your nutrient management practice needs to be far more PRECISE than a conventional practice to gain an advantage from the increased plant population. "Precision" means not applying too little, but it also means not applying too much; because everything in Agriculture has its limits. (See Nitrogen Management.)

With independent data like that from Asgrow and others, it makes you wonder why Successful Farming Magazine (parent magazine of agInnovator) is determined to boycott Soil Doctor® VR technology, until CTI gives SF its proprietary, internal data to review: Material which Competitors typically try to get out of CTI and CTI cooperators, but Material which holds no interest whatsoever for growers themselves.

Why is SF so overly-interested in material which --by definition-- is not independently verifiable and which growers have no desire to review; and so disinterested in the INDEPENDENT data, which is readily available, VERIFIABLE From INDEPENDENT, RESPECTED SOURCES, and is --IN TRUTH-- The ONLY DATA That GROWERS (SF readers) WANT and NEED to SEE?

Intriguing, isn't it?

To See CEC Maps of Mr. Holsapple's Jewett, IL Fields

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