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With the latest USDA forecast indicating a USA corn crop size of 14.0 billion bushel and soybean production at 3.26 billion bushel for 2013, these production levels for 2013 were not grown in the most favorable weather conditions.

There are two experiments at our Agronology 10 Research Center at Walcott, IA, which clearly demonstrates the need and value for sound ongoing fertility management practices.

Experiments

The first experiment “Critical Considerations” is a summary for the top 24 yielding corn plots in 2013.

The average yield for this grouping in 2013 was 233.7 bu/a.

Applied fertility facts for this group:

• Fall dribble band corn fertility program.
  • 23 of 24 had P&K applied in Fall 2012.
    • 16 of 23 plots were fertilized with 29-55-85.
    • 3 of 23 plots were fertilized with 29-50-75.
    • 2 of 23 plots were fertilized with 29-60-95.
    • 2 of 23 plots were fertilized with 29-45-65.
  • 21 of 23 plots were fertilized with sulfur (10-20 lbs/a) and zinc (0.428-0.749 lbs/a).
  • 18 of 23 plots also had boron added as the third micro-nutrient (0.2-.5 lbs/a).

In our second experiment, “Fertility Maintenance,” a corn fertility program of either 29-50-75-15s-.535Zn-.3B (200 bu. program) or 29-55-85-15s-.642Zn-.4B (220 bu. program) was dribble band in the fall 2012 for the 2013 corn crop.

A review of the proceeding year’s soybean fertility was interesting in how it influences the 2013 corn yield (Table 1).

Table 1: Influence of Soybean Fertility on 2013 Corn Yield

Dribble Band Soybean Fertility           Corn Yield (Bu/A)       Cost ($/A)        Net Benefit ($/A)

Tip #1

I would strongly recommend that you consider adding 10 lbs. s/a to the fall dribble band fertilizer application. Our normal P&K recommendation for 60 bu/a soybeans would be a 17-40-80.

Over a thirteen year time period (2001-2013), the addition of 10 lbs of sulfur enhanced yields by an average 2.2 bu/a per year. With soybeans at $12.50/bu and 10 lbs of sulfur costing $8.73/a, the net dollars per year would average $18.77.

In 2013, even better net dollars ($/a) were achieved when the 10 lbs of sulfur was added to our dribble banded P&K fertility program (Table 1).

 Table 1: Influence of Sulfur on Yields and Profitability in 2013
            Fertility (lbs/A)_____                           Yield                            ________$/A______
P&K Dribble Band        Sulfur                          Bu/A                            Cost                 Net

21-40-80                      ——-                            66.2                             —–                  —–
21-40-80                        10                              71.7                             8.73                 60.02_______
Soybeans:  $12.50/bu.
Sulfur:  454.10/T.

Tip #2

I would concur with University Soybean Specialists who are recommending seeding rates of 130,000-to-140,000 seeds/a.

At the Agronology 10 Research Center in 2013, we observed about a $28.00/a advantage with our 140,000 seeding rate (Table 2).

Table 2: Influence of Seeding Rate on Yields and Profits in Soybeans

__________$/A__________
Seeding Rate (Seeds/A)                      Yield (Bu/A)                    Seed Cost             Net

140,000                                                  84.8                               40.00                  28.30
177,200                                                  83.4                               50.63                  ——-_____________
Soybean Price:  $12.50/bu.
Planting Date: May 1, 2013.
Fall P&K: 21-50-100-10_s-1.3Mn.
Row Width: 15 inches.
Previous Crop: 6^th Year Corn.
Seed Cost:  $40.00/Bag @ 140,000 seeds.
Variety:  Asgrow AG 2731 Gen RR2Y.

Tip #3

I would encourage the employment of a late season (R₃-R₄) fungicide and insecticide treatment on soybeans. The data illustrates the value of this treatment (Table 3).

Table 3                 Influence of a Fungicide and Insecticide on 2013 Soybeans______________
                   Treatments______________       Yield                Harvest                           $/A_______
Products                                Rate (Oz/A)        Bu/A             Moisture (%)         Cost               Net

None                                           ——-              67.3                    12.0                ——              ——

Stratego YLD                                 4                 70.4                    11.9                19.62            19.13
Stratego YLD+Leverage 360     4+3.8              71.1                    11.8                27.12            20.38___
Variety: Asgrow AG 2933 Gen RR2Y.
Planting Date: May 1, 2013.
Soybeans: $12.50/bu.

If you are farming in the droughty area like we experienced at the Agronology 10 Research Center in Walcott, IA in 2013, we observed roughly a 25 bu/a corn difference in 2013 from 2012.

In 2013, our source of P and K for corn experiment averaged 193 bu/a for those 48 plots while in 2012, the yield for those 48 plots was 217 bu/a. The previous crop in both instances was soybeans. However, our 2013 corn on corn overall yields of 179 bu/a are slightly above our 2012 yield of 175 bu/a.

Experiments

Now, for a couple of experiments, the results showed that the complete N-P-K + micros in a dribble band were the way to go.

A basic corn fertility program of either 29-50-75-15s-.535zn-.3B or 29-55-85-15s-.642zn-.4B was dribble banded in Fall 2012 for the 2013 corn crop and the influence of the previous year’s soybean fertility program is shown in Table 1.

Table 1: Influence of Soybean Fertility on 2013 Corn Yields
Dribble Band Soybean Fertility                                Corn Yield (Bu/A)

17-40-80                                                                          189.7

17-40-80-1.3Mn                                                               190.1

17-40-80-10s                                                                   195.5
17-40-80-10s-1.3Mn                                                        200.0_________________

Results

From the Critical Consideration data for the top 24 yields which yielded 233.7 bu/a, a review for the applied fertilizer can be seen.

• For the fall dribble band: corn fertility.
  • 23 of the 24 plots had P&K applied in Fall 2012.
    • 2 of 23 plots had 29-45-65 applied.
    • 3 of 23 plots had 29-50-75 applied.
    • 16 of 23 plots had 29-55-85 applied.
    • 2 of 23 plots had 29-60-95 applied.
    • 21 of the 23 plots which had N-P-K applied also had sulfur and zinc applied.
  • 18 of the 23 plots which had N-P-K applied also had sulfur, zinc and boron applied.
  • For the fall dribble band: soybean fertility.
    • 23 of 24 plots had N-P-K applied for the prior year’s soybean with a fertility of 17-40-80 or greater.
    • 16 of 24 plots had 10 lbs. sulfur applied.
    • 13 of 20 soybean fertilized plots had a manganese application.

I believe that two factors had significant impact on this year’s corn.

Factor 1

First is the weather. Too much rainfall early and then a lack of rainfall at the end of the growing season, Table 1. That 0.75 inch rainfall in August really hurt!
Table 1: Weather at the Agronology 10 Research Center, Walcott, IA
                                                           Rainfall (inches)______________________________
Month             Norm*               2013                2012                2011                2010

April                 3.45                 8.25                 5.05                 3.40                 5.15

May                 4.25                10.35                3.75                  4.45                 5.55

June                 4.35                 4.75                 2.70                 4.00               11.00

July                  4.03                 2.55                 1.10                 3.70                 7.00
Aug                  4.41                 0.75                 4.25                 2.75                 5.41

Total               20.49               26.65               17.25               18.30               34.11
June-Aug       13.01                 8.05                 8.05                10.45               23.41________
*30 Year National Weather Service Data

Factor 2

Secondly, our corn crop had less available N to produce our corn crop. This reduced N availability was caused by:

• Denitrification of N.
• Slower mineralization of our organic nitrogen—organic matter and humus.
• Possibly greater than normal leaching losses of applied N thru our tile lines.

In our “Nitrogen Management” experiment, where an 18 oz. rate of Instinct was applied with 50 lbs. N yielded 167.3 bu/a, a 35 oz. rate of Instinct applied as a post-N application yielded 170.8 bu/a.

This post-N application was made on June 5, 2013 and the corn was in the V6 growth stage, this on a long-term continuous corn area.

In the “Nitrogen Rate” study, again another long-term continuous corn project, yields were increased as N rates went up, Table 2.

Table 2: Influence of Post N on 2013 Corn Yields
    N Rate (Lbs./A)__
Post*               Total            Yield (Bu/A)                     Harvest Moisture (%)

25                    175                  190.0                                       25.1

50                    200                  195.7                                       25.7
75                    225                  208.4                                       24.7                             __
*Applied on 4 June 2013

After reviewing the top 10 yields from our 2013 corn Critical Considerations data set, I have made the following observations.

Observations

• Average yield for this 10 plot group is 242.13 Bu/A.
• All 10 corn plots had a fall dribble N-P-K applied last fall.
• 8 of the 10 fall dribbled fertilized plots had a 29-55-85 applied.
• 9 of the 10 plots had a sulfur application (10 to 15 lbs./A).
• 9 of the 10 plots had a zinc application (.428 to .642 lbs./A).
• 7 of the 10 plots had a boron application (.2 to .4 lbs./A).
• 9 of the 10 plots had fertilizer applied (N-P-K) to both the corn and soybean crop directly.
• DeKalb DKC 62-97 VT3P RIB was utilized in 7 of the 10 plots.

 

 

 

With much of the 2013 soybean crop harvested, what can I comment on?

Observations

• I believe that soybean planting date did affect the 2013 soybean crop. Our soybean crop planted May 1, 2013 yielded approximately 70 Bu/A.
• Some varieties weathered the stresses of 2013 better than others. From our Soybean Management II experiment, we observed the following 2013 yield data:
  • Asgrow AG 2731 RR2Y      70.3 Bu/A.
  • Asgrow AG 2933 RR2Y      74.1 Bu/A.
  • Asgrow AG 2931 RR2Y      75.5 Bu/A.
• The “Critical Considerations” data set from the Agronology 10 Research Center at Walcott, IA showed that 17 of the 19 plots from this data set received a direct fertilization (N-P-K) for the soybeans.
  • Of these 17 plots which had N, P, K fertilizer applied, 16 also had a micro nutrient component. By the way, these 19 plots’ average yield was 81.8 Bu/A.
• The late season addition at R₃-R₄ growth stage of a fungicide and insecticide treatment did improve our soybean yields in 2013, as seen in Table 1.

Table 1: Influence of a Fungicide and Insecticide on 2013 Soybeans Treatments
Product                     Oz/A              Yield (Bu/A)                        Harvest Moisture (%)

None                           —–                    67.3                                            12.0

Stratego YLD                8                      70.4                                            11.9

Stratego YLD                8                      71.1                                            11.8
Leverage 360              3.8_________________________________________________

Wow! My corn and soybean harvest was completed on September 26.

Observations

Harvest lasted almost 4 days and we harvested approximately 30 acres of crop. Our top soybean yield in 2013 was almost 90 Bu/A, which is the 5^th highest individual yield since 1994 at the Agronology 10 Research Center in Walcott, IA.

 

As the end of August draws closer, my concerns are on our developing crop.

Observations

First, how much rainfall have you had during the month of August? Our 30 year average rainfall for August is 4.41 inches. At the Agronology 10 Research Center at Walcott, the rain gauge has been stuck on 0.75 inch of rainfall since August 6.

With this limited amount of rainfall, the daily rate of dry matter production (bu/a of grain) has slowed. This dry weather effect is possibly going to affect some of our later maturing crop the most. However, some good, timely rains up to crop maturity can add yield, but if the crop is dead, no amount of rainfall will revive the crop.

Examples

I am supplying rainfall amounts at the Agronology Center for the last four years (2010-2013) for comparisons.

Note the similar total rainfall amounts for June-August for 2012 and 2013, but the big difference in August rainfall amounts can have a significant effect on crop yield.

Late Summer Rainfall Amounts 2010-2013
Inches of Rainfall
Month                         2010             2011              2012              2013             Norm

June                           11.00             4.00               2.70               4.75               4.35

July                              7.00             3.70               1.10               2.55               4.03

August                         5.41             2.75               4.25               0.75*              4.41
Total                           23.41          10.45               8.05               8.05              12.79_

*Total thru 28 August 2013

 

While much of our current attention for crop development is on corn, let’s not forget our soybean crop.

Items to consider for the soybean crop

• On the longest day of the year, June 21, how much leaf area was present in your soybean field?
  • The more leaf area, the better the prospects are for higher yields.
• Average, or slightly above average, rainfall amounts in August generally are considered beneficial for high soybean yields.
  • The 30 year norm for August is approximately 4.4 inches of rain.
• Soybeans generally mature by calendar date rather than growing degree days as corn does.
  • From its normal maturation for each maturity grouping (MG), earlier plants will accelerate harvest by 5 to 7 days, while later than normal planting date will add 5 to 7 days to this general maturation date.
  • Cooler than normal temperatures will slow maturation slightly.

Observations

At the Agronology 10 Research Center, on June 21, our canopy in 15 inch row soybeans was completely covering the ground. On Monday, August 6, a large load of pods were filling throughout the soybean plant.

Our normal harvest date of 2.7 to 3.0 MG soybeans is the last week of September.

How far along is my corn crop this year?

For corn, remember that tasseling time (date) plus 60 days on average will give us approximately 32% moisture corn. If I add another 10-to-14 days to further field dry the crop then harvest of 25% to 27% moisture corn could be possible.

Example

For instance, my corn which tasseled on July 8-9 plus 60 day plus another 10 days for drying shows that harvest can possibly begin on September 17. I also had a portion of my corn crop which didn’t tassel until July 15-16, which means harvest could possibly begin on September 24, 2013.

Since 2010, my earliest corn harvest date was September 11-12, 2010. My latest harvest date was September 30-October 1, 2011.

My relative corn maturity is 110 to 112 day corn.