Another way of looking at this trial is to compare the GSP with the additives to the reduced fertilizer inputs. Figure 16 compares the Extract plus GSP to the reduced fertilizer with Extract and it also compares the Terramar plus GSP to the reduced fertilizer plus Terramar. This is where there is a lot to discuss. Beginning with the Extract treatments, the reduction of fertilizer resulted in lower yields. However, the 10% reduction resulted in a higher net return per acre than the GSP plus the Extract, therefore in this case it shows that it would be beneficial to reduce the fertilizer. Another interesting observation was that the 10% reduction resulted in 2.4% less yield and the 15% reduction resulted in 7.3% less yield with these not being proportional we feel that there are some interactions that are occurring with the products and fertilizer. When we compare the reductions to the GSP plus the additives we are even more confident in this systematic approach of reducing fertilizer inputs as all yields are similar to the checks. The largest deficit would be the 15% reduction using Extract but that deficit is only 7.3 bpa and in reality that is within 2.48% of the check. The next logical step would be to continue to look at these types of trials and create a database of replicated data. Future trials also need to include GSP at reductions to match the reductions with the additives, to help us better understand the value of the additives.
Fertilizer Use Efficiency Trials
GSP + 1 qt/ac Terramar + 2 qt/ac Blackmax22 + 2 gal/ac Altura
10% Reduction of GSP plus Terramar Blackmax22 + Altura
15% Reduction of GSP plus Terramar Blackmax22 + Altura
GSP + 2 Qt/ac Extract + 2qt/ac Blackmax22 + 2 gal/acAltura
10% reduction of GSP plus Extract Blackmax22 + Altura
15% reduction of GSP plus Extract Blackmax22 + Altura
Moisture Yield 15.0 Grain Price
14.6
14.9
14.5
14.3
14.4
13.3
290.2 $7.02
287.8 $7.02
283.0 $7.02
285.1 $7.02
281.5 $7.02
283.8 $7.02
Difference from Check Percent change in yield Savings at % Reduction
-2.4
-7.3
-3.6
-1.3
-0.83
-2.48
-1.26
-0.46
$22.63
$33.95
$22.63
$33.95
Net Revenue
$2,037.37
$2,043.13
$2,020.31
$2,001.57
$1,998.86
$2,026.16
Difference from Check
$5.76
-$17.06
-$2.71
$24.59
Figure 16. Another way to look at the Fertilizer use efficiency data.
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