Small Grain Research Menu

Results of Funded Research

Joint Project Between UK, Wheat Tech, Inc. and Miles Opti-Crop

Final Report (UK)
Final Report (Wheat Tech)
Final Report (Opti-Crop)

Final Report
1998-99
University of Kentucky
Lloyd Murdock, Jim Herbek, John James, and Dottie Call

RESEARCH OBJECTIVE
This study will compliment other studies investigating practices that would best allow for no-till planting of wheat into corn residue. This study continues the comparison of different methods and timing of mechanical shredding of corn stalks of different corn maturities against no shredding and no corn residue.

COMPARISON STUDIES
This study is one of three studies designed to look at several different methods of residue management. The different studies will be conducted by Miles Opti-Crop, Wheat Tech, and the University of Kentucky.

RESEARCH TREATMENTS
1.    Remove all corn residue and plant into clean residue conditions (full season corn).
2.    Plant at an angle into standing harvested corn stalks (full season corn).
3.    Plant directly into standing corn residue, not angled (full season corn).
4.    Plant directly into standing corn residue, not angled (full season corn). Increased wheat seeding rate (15%).
5.    Plant directly into standing corn residue, not angled (early season corn).
6.    Rotary mow corn residue after harvest and plant into mowed residue (full season corn).
7.    Flail mow corn residue after harvest and plant into mowed residue (full season corn).
8.    Flail mow corn residue after harvest and plant into mowed residue (early season corn).
9.    Plant directly into standing harvested corn and flail mow after planting (full season corn).
10.    Flail mow corn residue after harvest and plant into mowed residue (full season corn). Spray UAN on residue at 40 lb/ac N immediately after harvest.
11.    Flail mow corn residue after harvest and plant into mowed residue (full season corn). Apply solid Ammonium Nitrate at 40 lb/ac N after wheat planting.

METHODS
Corn was planted at the rate of 26,000 seeds/ac using an early season variety (Pioneer 33Y18) and a late variety (Pioneer 3167). The average yields of the corn was bu/ac for the late season and bu/ac for the early season. Both varieties were harvested at 19% moisture and harvest dates were 8-26-98 and 9-8-98 for the early and late corn.

All mechanical shredding was completed immediately after harvest of each corn variety, except for Treatment 9 which was flailed immediately after wheat planting. All residue was removed from Treatment 1, but the plots were not tilled.

Wheat (Pioneer 2540) was planted no-till at the rate of 35 seeds/sq ft. with a 7 inch row spacing. Gramoxone was applied after planting and a total of 120 lbs/ac of N was applied with 2 on Feb. 10 and 2 on March 18. Harmony Extra was applied on March 29 and Tilt on May 3 and Warrior insecticide on Nov. 12 and Dec. 16.

RESULTS
1.    Residue   
The amount of residue cover after planting is shown in Table 1. Only 7% of area was covered when the residue was removed. When the residue was not removed, two treatments resulted in less residue after planting than the other treatments. Planting directly into standing stalks of early maturing corn and spraying 40 lb/ac of N as UAN on full season corn stalks both resulted in less residue after wheat planting. This was probably due to a more decomposition of the corn stalks prior to planting.

2.    Wheat Stands
Stands of wheat in the fall are seen in Table 2. The highest stands were in the treatment with a 15% increase in seeding rate and the treatment with all residue removed. The treatment with UAN sprayed on residue after corn harvest resulted in one of the higher wheat stand counts and lowest corn residue covers.

There was no difference between any of the other treatments. So, shredding or not shredding was not an issue as well as early or late maturing corn.

In 1998, flail shredding stands were better than the rotary mowed or planting into standing corn treatments. There was no difference in 1999 and some of this may have been due to excellent stand establishment weather conditions.

3.    Visual Observation During Spring Growth
The warm winter and early spring encouraged high tillering and high amounts of growth on all plots. Unlike last year, there were no visual differences in the treatments during the season. The only exception was where nitrogen was applied in the fall which caused these treatments to have more growth and lodging during the season.

4.     Yields
The yields are found in Table 3 and are very high this year due to favorable weather conditions. Head counts were high in all the treatments due to the warm winter so there was very little correlation between stands and yields. In fact, the treatment where all the residue was removed had one of the highest stand counts but the lowest yield.

The highest yield occurred where the residue was left standing and the wheat was planted at an angle (diagonally) to the old corn rows. Flail mowing treatments also had some of the higher yielding treatments.

Basically, there was little difference between yield. It appears that fall application of nitrogen, as well as removing of the residue, before wheat planting were not helpful.

5. Double-Cropped Soybean Stands
Doubled-cropped soybeans planted after wheat harvest (Table 4) give some interesting results. All stands were adequate for maximum soybean yields and the differences were relatively simple. Planting wheat diagonally across old corn rows resulted in best soybean stands in 1998 but was among the lowest in 1999. Soybean stands behind rotary mowed corn stalks before planting of what was low both years so this may not be the best practice concerning double-cropped planting.

The 15% increase in seeding rate also resulted in less double-cropped soybean stands. This practice may increase the planting problems with soybeans.

All other treatments resulted in excellent stands showing little differences over the two years.

CONCLUSIONS
There were little differences in stand counts or yields for any of the treatments. Excellent stands were achieved by all methods used. The 15% increased seeding rate treatment and the removing of the entire corn residue gave slightly higher stands but the increase was small and did not result in higher yields.

The favorable winter and spring conditions resulted in excellent tillering and high yields on all treatments in 1999.

The conditions in 1998 were not as favorable and flail shredding of corn was a favored treatment. The experiment results in more helpful information during unfavorable years.

TOP

Final Report for 1999
Scott Jones of Wheat Tech, Inc.
 
Our goal in this project is to determine what, if any, means are efficient in offsetting the ill effects of corn residue when no-tilling wheat.  Through guidance from the Kentucky Small Grain Grower’s Association and Dr. Lloyd Murdock of the University of Kentucky, we chose to include treatments where rotary mowing and liquid nitrogen was used prior to planting in an attempt to hasten the degradation of the corn stalks.

Five replications of the treatments listed in Table 1 were established on Long Vue Farms near Allensville, KY.  The cooperator, Mr. Larry Thompson, arranged a preplant application of fertilizer with an analysis of 23-71-0 following corn harvest.  Early preplant rotary mower applications were conducted using a six foot Rhino mower.  The early preplant nitrogen applications were made using either 28% UAN solution or urea as indicated by the treatment list. 

Table 1

It has been standard practice to use increased seeding rates when no-tilling into heavy residue; therefore, we incorporated two no-till seeding rates into the treatment list.  The early preplant application of 28% UAN solution was used as a method of above ground stalk degradation.  The treatments where urea was used is an attempt to provide the same amount of nitrogen to act as a food source for the plant rather than to aid residue decomposition.  This treatment could shed light on the amount of nitrogen required for adequate fall tillering in no-till wheat.  One treatment included only planting the wheat at an angle into standing corn stalks.  This is what most growers consider as standard practice when following corn.  1.5 pt/A Gramoxone Extra was applied as a burndown to remove any early weed competition in the no-till treatments.

A conventional tillage treatment was established using a six-foot rotary hoe for incorporating the residue into the soil.  Tillage depth in this treatment was six inches and closely simulated the incorporation of stalks received after two disc passes.  Standard seeding rates were used in these plots.

Standard upkeep of the plots consistent with intensive management practices was maintained throughout the growing season.  Spring nitrogen was split applied with 35 lbs N put on at Feekes growth stage 3 (February 23rd) and 70 lbs N put on at Feekes growth stage 6 (March 22nd).  An additional 20 lbs N was applied at Feekes growth stage 6 on one of the treatments in an attempt to determine economic threshold for spring nitrogen.  In all cases, spring nitrogen applications were made using UAN solutions applied with streambars.

With garlic and aphids present in the plot, a spring application of Harmony Extra (0.5 oz/A) tankmixed with Warrior (2.56 oz/A) was made March 31st using flat fans to deliver 15 gpa.  Foliar disease problems were minimized by an application of Tilt (4 oz/A) on May 2nd using the same delivery method.

Percent ground cover notes were taken in all plots after planting.  The results indicate that there was no statistical change in percent ground cover with respect to rotary mowing or the addition of early preplant nitrogen (either source).  However, the conventional tillage did reduce percent ground cover from an average of 63.93% in the no-till treatments to 24.20%.

One of the main issues in no-till is stand establishment.  As a measure of this, stand counts were taken after emergence and converted to percent emergence so all seeding rates could be compared.  These values are shown Table 2.

These results indicate strongly that a larger percentage of the wheat seed germinates and produces plants in a conventional seedbed.  There was no statistical advantage in applying nitrogen either as a food source or to aid in stalk decomposition prior to planting with regard to increasing germination percentage.  Although not statistically significant, the difference in germination percent between the rotary mowed and planted at an angle treatments (375 seeds/yd2) were noticeable.  This supports the theory that a consistent layer of residue, like that achieved after mowing, provides the wheat drill a better opportunity to deliver more accurate seed placement facilitating better seed to soil contact.

Table 2

Where Table 2 indicated percent emergence, it should be noted that final stand is also important in deciding proper seeding rates.  Table 3 uses the same initial stand count to provide data relating the emergence/yard2.  This data shows that an adequate stand is provided in the no-till plots where rotary mowing is used to chop and evenly distribute the residue.

Table 3 

The emergence data in this format better exemplifies the increase in plant population with degradation of the corn residue prior to planting and the importance of increased seeding rates.  It is these two factors that get the stand established.  In order to maintain these plants and their tillers, good seed to soil contact must have been achieved at planting in order to avoid losses associated with winter freezes and sufficient nitrogen must be available to the plants in the spring.

The fairly mild winter experienced in south central Kentucky proved favorable for no-till wheat production.  There were no extended periods of extremely cold temperatures that are capable of reducing plant stands.  Therefore, the initial good stands in the fall carried over to excellent head counts in the spring as indicated in Table 4.

Table 4

The five replicates of the trial were harvested June 5th and subsequent yields are listed in Table 5.  When comparing Table 4 and Table 5, it is not surprising that the overall plot produced excellent yields.  Head counts are usually good predictors of yield potential.  It is interesting to note that the second highest yield resulted from the lowest head count.  This occurred in the treatment where 20 lbs additional nitrogen was applied at Feekes 6.  This exemplifies the role of nitrogen in a no-till environment.

Table 5

It is not surprising that the conventional plot produced the lowest (numerical) yield. To fully understand why this happened, we must consider the variety used in this trial. Pioneer 2545 is a full season wheat. It was selected in this trial for its excelletn winter hardiness and adaptability in no-till environments. As with most full season wheats, Pioneer 2545 is susceptible to drought. The extremely dry conditions experienced in south central Kentucky this wheat season was exaggerated by the lack of moisture saving residue in the conventional treatment. The conventional plot provided the highest percent emergence (Table 2), the highest stand count (Table 3) and a very adequate head count (Table 4), but lacked enough moisture to take advantage of the yield potential.

This season, the growing conditions favored no-till wheat production. It has been demonstrated in the past that residue has limited the success of no-till by reducing plant stands and making the established plants more susceptible to winter kill and spring freeze injury. With that absence of these factors, this year has shown that no-till wheat is capable of producing excellent if not superior yields.

TOP

Final Report
Submitted by Miles Opti-Crop, Phillip Needham
 
 
This study is one of three designed to research different tillage and corn residue destruction principles across different regions of Kentucky.  The objective was to determine the relative yields between the different tillage and no-tillage systems so that producers can decide which principle will best suit their operation.  The three different studies are conducted by The University of Kentucky (Dr. Larry Grabau), Wheat Tech (Scott Jones), and Miles Opti-Crop (Phil Needham). 

The purpose of this study was to determine the relative yields between different tillage and no-tillage systems.  The six systems researched and replicated were as follows:

1.  Conventional tillage (bush-hog, disc + roller x 1, disc chisel x 1, disc and roller x 2)
2.  No-Till with corn residue burnt 10 days prior to wheat planting
3.  Disc chiseled (disc chisel x 1, disc + roller x 1)
4.  Minimum tillage (disc and roller x 1)
5.  No-Till into standing stalks
6.  No-Till with stalks bush-hogged preplant

In mid-September, two weeks after corn harvest, all of the plots were prepared to give the tillage treatments time to help decompose the reside.  All tillage plots were cultivated once prior to drilling, and these passes are included in the table above.
 
Approximately six weeks after corn harvest and following a heavy rain in early October, the plots were planted on October 13th into seedbed conditions that were both firm and moist.  The firm soil conditions allowed seeding depth to be controlled accurately and the moisture levels present allowed rapid germination and emergence.

Stand counts and residue % levels were determined in early November.  The results are documented in the table below.

All of the replicated plots survived the winter very well.  The No-Till with stalks burnt looked the very best right from emergence due to no hindrance of residue tying up residual nitrogen or hindering seed placement.  Emerging stands in both of the No-Till into residue replications were very erratic, with small voids and no wheat plants present.  In higher residue locations, these voids remained until harvest.
 
On May 19th, all of the plots were analyzed with regards to the head count per square yard and the number of respective spikelets on each head.  The results are documented below.

Harvest of the plots was carried out on June 26th.  The yields, moisture levels, and test weights are reported below.

Conclusion
 
The levels of previous crop residue prior to planting the wheat were considered to be above average; however, there was a time interval of almost six weeks between corn harvest and planting of the wheat.  This extended period with limited rainfall allowed the residue to decompose to an extent by which it did not severely impact the no-till planting of the wheat.  Therefore, it is my opinion that even with significant levels of residue present on the soil surface, the level of decomposition was high enough to facilitate easier than normal no-till wheat planting.  In the majority of the wheat regions of the state, I believe that most growers will not have the luxury of six weeks residue decomposition prior to planting.  In some later corn harvest years, especially in Western KY and wetter soils, growers may be fortunate to have two weeks between corn harvest and wheat planting.
 
The yield results were surprising to most of us that worked in the plots this year.  Most of us expected significantly higher yields in the stalks burnt and conventional seedbed conditions, as a result of more uniform plant stands and improved color.  We believe the residue decomposition status, plus the issue that the spring of 1999 provided such good growing conditions, masked most of the seedbed management practices

TOP