November Highlightsm Grid Sampling Review  10/31/16 9:43:06 AM

November Highlights

Fertilizer Prices—Overall, fertilizer is 20+ percent less than last year at this time

Weed Control--Now is an ideal time fall applications of Authority, Valor, or Trivence for marestail and additional winter annual weed control for 2017 soybean acres.

Soil Sampling--Remember to replace what you harvest---record crops will  remove record amounts of fertility—soil sampling gives you an idea of what was removed and what is needed for the 2017 planting intentions.  (See added info. and table below)

Seed Price Discounts 12% Volume, 8% Cash by Nov. 22nd 2016

                                    12% Volume, 6% Cash till Jan. 20th 2017

WBI offers a 12% volume discount to all growers regardless of the number of units. These discounts are taken off the list price of the seed on the date of purchase.  Aggressive, additional discount programs available for qualifying orders.


Yield Data—The yield grid for corn and soybeans is still in progress as we continue to finish corn and soybean plot harvest.  We can offer some additional data when looking at total field averages

AG3432—77.2 acre dry land average yield of 80.62 bu/acre on a 13% moisture equivalent.


AG3832—117.5 acre dry land average yield of 75.01 bu/acre on a 13% moisture equivalent.


AG4034 --251 acre dry land average yield of 78.2 bu/acre on a 13% moisture equivalent.


Historic Grid Sampling info—Given the current economics of crop production, I have gone back into our archives and found an article we ran in the fall of 2013 dealing with the agronomic and subsequent economic benefits of grid sampling and 2 extremely different 2.5 acre grids we have right around the  plant over the course of 4 years.  Since 2013 the margin of production differences has continued to narrow and the overall input cost has lessened. 

Below is an example of the Marshall Silty Clay Loam soil association we have surrounding the plant in Plattsmouth. The Marshall association is generally deep in profile, well drained silty soils formed in loess (Loess is sediment formed by the accumulation of wind-blown silt, , twenty percent or less clay and the balance equal parts sand and silt that are loosely cemented by calcium carbonate). We began grid sampling and fertilizing accordingly since 2010. We have a pH range from 5.4 to 6.7, organic matter range from 2.3 to 4.5, and a CEC range from 16.9 to 25.2 in the same 94 acre field. I selected 2-2.5 acre random grids within the field for comparison on nutrient levels and subsequent yield from 2010, 2011, 2012 and 2013.  So we have two years of data from corn and soybeans to consider.




Grid A

Grid B

Field Ave





Organic Matter








P1 Phosphorus

12 ppm

161 ppm

31.3 ppm

P2 Phosphorus

20 ppm

162 ppm

42.20 oom


9 ppm

20 ppm

10.51 ppm


186 ppm

662 ppm

274.94 ppm


1.1 ppm

5.2 ppm

1.93 ppm

2010 Corn Yield

147 bu./acre

195 bu./acre

178.49 bu./acre

Applied 80 lbs of P--blanket treatment to whole field-Fall 2010




2011 Soybean Yield

32 bu./acre

66 bu./acre

62.52 bu./acre

Applied –Fall 2011

193.12 lbs of 11-52-0 MAP

121.71 lbs of 11-52-0 MAP

174.26 of 11-52-0 MAP

2012 Corn Yield

116 bu./acre

145.6 bu/acre

126.45 bu./acre

Applied –Fall 2012

147.92 lbs of 11-52-0 MAP

90.89 lbs of 11-52-0 MAP

121.61 lbs of 11-52-0 MAP

2013 Soybean Yield

57.25 bu./acre

62.58 bu./acre

56.49 bu./acre

Applied 112 lbs of P--blanket treatment to whole field—Applied Fall 2013




Fall 2013








Organic Matter








P1 Phosphorus

40 ppm

159 ppm

64.41 ppm

P2 Phosphorus

56 ppm

148 ppm

100.06 ppm


12 ppm

19 ppm

13.14 ppm


235 ppm

401 ppm

228.47 ppm


1.5 ppm

7.7 ppm

2.79 ppm


Obviously the level of base-line fertility and nutrients subsequently applied varied widely between these two grids. The challenge was/is to maintain the high fertility levels and since we have identified the lower fertility leveled areas (Grid A)—we wanted to bring these levels up to increase production. The Grid Sampling Value is seen here as we don’t have to do too much fertility work in Grid B and we take those dollars and apply them for fertility in Grid A. Remember that the goal is to narrow the gap between your low and high producing areas of the field.

RESULTS—in 2010 we had a corn yield gap of 48 bushels/acre between grids A and B.  In 2012 the gap narrowed to 29.6 bushels/acre In 2011 we had a soybean yield gap of 34 bushels/acre between grids A and B.  In 2013 the gap narrowed to 5.33 bushels to the acre.  Consider the residual fertility numbers for (Grid A—Lower Fertility) in 2010 vs. 2013.  Through one blanket treatment of phosphorus (2010) and two prescribed treatments of 11-52-0 per grid,(2011 and 2012)  Phosphorus P1 levels have increased 28 ppm, P2 levels increased 26 ppm, Sulfur increased 3 ppm, Zinc increased 0.4 ppm—all within 4 years on Grid A.   Also, consider the overall field average—especially when the past 2 years have been fairly dry.  I would not have guessed the field average in the drought of 2012 to be 126 bu./acre or anywhere in that field have a yield of 145.6 bu./acre (Grid B)—especially when the field was wilting from moisture stress at V8—Hip high.  Who would have thought we could have had an average soybean yield of 56.49 bushels per acre in 2013 when we received only 1.40” of rain for the entire months of July and August.  The wet 2013 spring certainly played a role here.  Bottom Line--Balanced fertility levels aid in crop performance within dry growing conditions.  The grid sampling practice has narrowed our fertility extremes and decreased the yield gaps within the same field.  Our goal is to be in position fertility wise to take advantage of the rains when they come and also buy some time within peak water stress times of crop development if the rains are not a frequent as we would like. 



Fall applied nitrogen?

While it may save time for spring field work, are there risks involved?  Growers need to consider several things: 1) soil temperature (currently in the mid to high 50’s at 4” depth)  and 2) soil moisture. Why the concern over temperature and moisture?


When anhydrous ammonia is applied, it reacts with soil moisture to form the ammonium ion (NH4), which can readily attach to clay particles in the soil and is not subject to losses at that point. Over a period of several weeks, NH4 can be converted, through a series of steps known as nitrification, to nitrate (NO3) if soil temperatures are above 50 degrees F. In fact, nitrification begins to occur at soil temperatures of 30 degrees, and increases as soil temperature increases. Soil moisture also is a factor in the rate at which this occurs. A simplified illustration of the process is:


Ammonium à Nitrite à Nitrate

(NH4)           (NO2)     (NO3)


Two groups of bacteria are involved in the conversion process: nitrosommonas in the conversion of ammonia to nitrite, and nitrobacter are responsible for converting nitrite to nitrate. These steps occur in rapid succession to avoid a buildup of nitrite (NO2)  in the soil. The end result, nitrate (NO3),  is the form of nitrogen that is susceptible to leaching. Therefore, it is necessary to delay fall ammonia applications  after soil temperatures have fallen below at least 50 degrees, meaning a decrease in the activity of the bacteria. The more nitrogen that is maintained in an ammonical form, the less chances for losses between now and next planting season, since


Another reason to consider soil moisture conditions is the potential losses by applying anhydrous ammonia into hard and/or dry soil. This form of N has a high attraction to water, which is necessary to “hold” ammonia in the soil, and reduce losses immediately after injection. If there is a problem with loosing ammonia to the air, then growers may need to: 1) wait for better soil moisture conditions (wetter), 2) consider the use of covering disks on the ammonia applicator or 3) implement the use of an N-Serve, or urease inhibitor type additive in the anhydrous application. These additives can aid in minimizing anhydrous losses in warm and drier conditions..




John W. McNamara


Wiles Bros. Inc.

606 Wiles Road

Plattsmouth NE. 68048

(402) 298-8550--Office

(402) 499-3870--Cell

(402) 298-7174--Fax




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