By David Nicolai, IAP Coordinator

Due to the late harvest the early discounted registration rate has been extended until November 27th for the Minnesota Crop Pest Managagement Short Course and Minnesota Crop Production Retailers Trade Show set for December 8th through the 10th, 2009 at the Minneapolis Convention Center.  The 3-day program starts Tuesday, December 8th with the TSP recertification program and MCPR's plenary session and annual meeting.  On Wednesday, December 9th, the program will continue with pesticide applicator recertification for categories A (Core) and C (Field Crop Pest Management) and the Crop Pest Management Short Course.

The concurrent sessions at the CPM shortcourse continue on Thursday, December 10th, with a wealth of pests, crop and fertility management topics including foliar fertilizer research for corn & soybeans, corn residue management, probabilities of corn yield responses to foliar fungicide, using precision farming tools to maximize profit by developing a site specific recommendation for corn plant populations and herbicide resistant weed management. The program will end Thursday afternoon at 3:00 pm to allow for a timely return home.

All concurrent sessions will run for 50 minutes and offer 1.0 CCA CEU/topic.  The full program can be reviewed by visiting the Crop Pest Management Short Course page (www.extension.umn.edu/AgProfessionals/cpmshortcourse.html)  located at the Institute for Ag Professionals website.

The NRCS will provide USDA Technical Service Provider training on December 8th. The program covers using the Web Soil Survey to locate soils with high leaching and runoff potentials; Programs, Practices, Guidance and people to help manage nutrients and pesticides in Well-head Protection Areas and using the NRCS website to access information.

The pesticide applicator recertification program for categories A (General Ground) and C (Field Crop Pest Management) is planned for all day Wednesday, December 9th, and will be last offering for recertification in 2009. 

 The registration fees for the 2009 CPM Short Course and MCPR Trade Show are as follows: 

Basic Registration (on or before 11/27/2009) - $115.00
Basic Registration (after 11/27/2009) - $140.00

Pesticide Applicator Recertification (on or before 11/27/2009)- $125.00
Pesticide Applicator Recertification (after 11/27/2009) - $150.00

Basic short course registration and pesticide applicator recertification registration plus hotel reservations can be accomplished by following the directions listed at the Minnesota Crop Retailers CPM web page.

 You may also register by completing the registration form.  Fax the completed form to 952-835-4774 or mail it to the following address:

MCPR
7500 Flying Cloud Drive
Eden Prairie, MN 55344

 If you have questions about the CPM Short Course, contact David Nicolai (612-625-2778).   Questions regarding the pesticide applicator recertification can be directed to Dean Herzfeld by calling (612) 624-3477.  For all other questions pertaining the 2009 CPM Short Course and MCPR Trade Show contact Jessi Brunelle at the Minnesota Crop Production Retailers (952-253-6244).

Recently there have been numerous reports of "moldy corn" across Minnesota. The late harvest, high moisture corn, and continuing wet conditions have contributed to this problem. At least two main questions should be considered. Are the problems at this point significant ear and kernel rots that are damaging the kernels, or is the problem primarily superficial growth of fungi on the grain surfaces? Both types of fungal growth on corn can cause greater problems with grain quality if the corn is not harvested and dried properly. The current problems with "moldy corn" are still not completely clear, but we can make some general comments on what we have seen and heard so far.

Several types of ear and kernel rots and fungal growth and can occur on corn in MN, especially Fusarium ear rot, Gibberella ear rot, and Aspergillis ear rot. Aspergillis ear rot is generally of greatest concern on corn due to potential production of aflatoxin, but the cool summer this year did not favor it in most parts of Minnesota. Diplodia ear rot appears to be very uncommon in Minnesota. Other types of common fungi that may grow on corn include Penicillium and Trichoderma, and these may often have a superficial growth habit. More information on ear and kernel rot fungi and mycotoxins can be found at these web sites.(http://www.extension.umn.edu/cropenews/2007/07MNCN42.html, http://agcrops.osu.edu/corn/EARABNORMALITIES.php#Diplodia, http://www.uwex.edu/ces/crops/MoldsMycotoxins.pdf)

By Lizabeth Stahl and Bill Wilcke

Extension Educator - Crops and Extension Agricultural Engineer

Soybean moisture levels of 16 to 20% or more at harvest have been reported throughout the state as this challenging harvest season continues.  If storage temperatures are below about 60F, soybeans at 13% moisture can usually be kept for about 6 months without having mold problems.  At a higher moisture content, how long can soybeans be stored before mold becomes a concern? 

The following table was developed for corn so to adjust for soybeans, simply look at the column for a moisture content 2 percentage points greater than the content of the soybeans in question.  For example, 18% moisture soybeans (look at the column for 20% moisture corn) at a temperature of 50F could be stored for about 63 days before there would be enough mold growth to cause price discounts or feeding problems.  Note that aeration is always recommended with all storage facilities.    

Reprinted from:  Natural-Air Corn Drying in the Upper Midwest, William Wilcke and R. Vance Morey, WW-6577-GO, 1995. http://www.extension.umn.edu/distribution/cropsystems/DC6577.html

Artificial drying of soybeans will be needed if soybeans are harvested and stored at a moisture content greater than 13%.  The article "Soybean Drying, Handling, and Storage" by Bill Wilcke, Vance Morey, and Ken Hellevang http://www.soybeans.umn.edu/crop/harvest/index.htm discusses recommended options and guidelines, and is recommended reading if you are needing to dry soybeans.  The bulletin  "Natural-Air Corn Drying in the Upper Midwest" by Bill Wilcke and Vance Morey, http://www.extension.umn.edu/distribution/cropsystems/DC6577.html,  is also useful as many of the principles for drying corn will be similar for drying soybeans. 

The soybean drying article, the natural-air corn drying bulletin, and some other post-harvest information can be found on the post-harvest website at:  http://www.bbe.umn.edu/Post-Harvest_Handling_of_Crops

Ken Hellevang, NDSU Agricultural Engineer, just released an article on soybean drying and storage advice on 10/20/2009, and rather than re-word what he has already said well, his article is attached below in its entirety, with his permission. Remember that this article was written for a northern location. In southern MN, natural-air drying usually works for about two weeks longer - until about December 1.

NDSU Offers Soybean Drying, Storage Advice

NDSU's grain-drying expert offers tips on drying and storing soybeans.

A challenging soybean harvest is creating many questions related to storage and drying, according to Ken Hellevang, agricultural engineer with the North Dakota State University Extension Service.

Soybeans at 11 percent moisture have similar storage characteristics to wheat or corn at 13 percent moisture, so an allowable storage time chart for cereal grains can be used to estimate allowable storage times for soybeans. For example, soybeans at 18 percent moisture content would be similar to cereal grains at 20 percent moisture, so soybeans would be expected to have an allowable storage time of about 50 days at 50 degrees. The allowable storage time is reduced to 25 days at 60 degrees and extended to about 90 days at 40 degrees.

The amount of natural air drying that will occur in late October and November is limited. The equilibrium moisture content of soybeans for air at 40 degrees and 70 percent relative humidity is 13.5 percent. An airflow rate of 1 cubic foot per minute per bushel (cfm/bu) is expected to dry soybeans with 18 percent moisture in about 70 days. Adding supplemental heat to raise the air temperature by 5 degrees will permit drying the soybeans to about 11 percent moisture in about 55 days.

Only about one-half of the beans would be expected to dry by mid-November, when outdoor temperatures become too cold to dry efficiently. Adding heat would cause the beans on the bottom of the bin to be dried to a lower moisture content and it would increase drying speed only slightly. Cool the soybeans to between 20 and 30 degrees for winter storage and complete drying in the spring. Hellevang recommends starting to dry when outdoor temperatures are averaging about 40 degrees.

Increasing the airflow rate will increase the drying speed. However, the fan horsepower required to achieve the higher airflow rate becomes excessive unless the grain depth is very shallow. For a soybean depth of 22 feet, the rule of thumb is that each 1,000 bushels of soybeans will need fan horsepower of about 1. Achieving an airflow rate of 1.5 cfm/bu will require about 2.5 horsepower and an airflow rate of 2 cfm/bu will need about 5 horsepower.

The type of fan greatly affects the airflow provided per horsepower, so use a fan selection software program such as the one developed by the University of Minnesota. It is available on the NDSU grain drying and storage Web site at http://www.ag.ndsu.nodak.edu/abeng/postharvest.htm. You also can use the chart for your fan that shows the amount of airflow delivered at various static pressures.

Soybeans can be dried in a high-temperature dryer, but the plenum temperature needs to be limited to minimize damage to the beans. Refer to the manufacturer's recommendations for maximum drying temperature. Typically the maximum drying temperature for nonfood soybeans is about 130 degrees. Even at that temperature, some skins and beans will be cracked.

One study found that with a dryer temperature of 130 degrees, 50 percent to 90 percent of the skins were cracked and 20 percent to 70 percent of the beans were cracked. Another study found that 30 percent of the seed coats were cracked if the drying air relative humidity was 30 percent, and 50 percent of the skins and about 8 percent of the beans were cracked at 20 percent relative humidity.

The relative humidity is reduced by one-half for each 20 degrees that the air is warmed. Therefore, if air at 40 degrees and 80 percent relative humidity is warmed to 60 degrees, the relative humidity is reduced to 40 percent, and if it is heated to 80 degrees, the relative humidity is reduced to 20 percent. Monitor the amount of damage occurring during drying and regulate the plenum temperature to obtain the acceptable amount of damage.

Food soybeans and seed beans must not have damage to the seed coat, so natural-air or low-temperature drying is the preferred drying method, Hellevang says.

Source:  Ken Hellevang, (701) 231-7243, kenneth.hellevang@ndsu.edu, Editor:  Ellen Crawford, (701) 231-5391, ellen.crawford@ndsu.edu.

Combine Adjustment:

With the 2009 growing season winding down, now is the time to prepare for corn harvest and start thinking about next year. Volunteer corn in soybean fields serves as a reminder to properly adjust combines. In addition to being an eyesore, volunteer corn can cause significant economical losses through added weed control costs and lost bushels at harvest. It only takes two corn kernels on the ground per square foot to equal one bushel per acre (Carlson and Clay, 2002), and that's not to mention dropped whole and partial ears that contain hundreds kernels. For specific suggestions on combine adjustment, see the article from Mark Hanna of Iowa State University: http://www.extension.iastate.edu/CropNews/2009/0903hanna.htm

Yield Monitor Calibration:

Another component of most combines is a yield monitor. This valuable tool must not be forgotten in harvest preparations. Yield monitors provide vital data with which to make hybrid and maturity comparisons. The well-below normal rainfall in much of Minnesota this year will likely increase variability in grain yield and harvest moisture within and among fields, making proper calibration of yield monitors even more critical. For specific information on yield monitor calibration, see the following article from Bob Nielsen of Purdue University: http://www.agry.purdue.edu/ext/corn/news/timeless/YldMonCalibr.html

Stalk Strength:

Harvest preparation should also include a walk through the fields to determine stalk strength. This is particularly important in fields that have experienced considerable moisture stress. Pushing plants, pinching lower internodes, and splitting lower stalks will indicate whether stalk strength has been compromised by stalk rot. Stalk strength can easily be evaluated using the push test, where plants are pushed 45 degrees (about 10 inches) from vertical at ear level. Plants that break following the push test are at risk for stalk lodging. Stalk strength can also be evaluated by pinching the lower stalk at the first internode above the brace roots, as hollow and deteriorated stalks will easily collapse when pinched.

With both the push and pinch tests, a minimum of 20 plants should be tested in five representative locations within a field (Malvick and Nicolai, 2005). Fields with 10 to 15% or more of the plants failing the push or pinch test are at risk for severe stalk lodging, and should be put on top of the harvest list to prevent harvesting downed corn later. For a complete set of photos and more discussion, see the following article from Bob Nielsen of Purdue University: http://www.agry.purdue.edu/ext/corn/news/timeless/StalkHealth.html

Yield Estimation:

Yield can be estimated prior to harvest using the following procedure, but accurate yield estimation requires multiple samples from representative locations throughout a field (Nielsen, 2008).

1)      Step off the length of row equal to 1/1000^th of an acre (17 feet 5 inches in 30-inch rows or 23 feet 9 inches in 22-inch rows) and count the number of harvestable ears in that length of row.

2)      Husk every fifth ear (only husk representative ears), and count the number of rows per ear (always an even number) and the approximate number of kernels per row.

3)      Calculate the average number of rows per ear and kernels per row from the husked ears.

4)      Estimate the number of kernels per ear by multiplying the average number of rows by the average number of kernels per row.

5)      Multiply kernels per ear by the number of harvestable ears in 1/1000^th of an acre to estimate the number of kernels per acre.

6)      Divide the number of kernels per acre by 90 (assuming 90,000 kernels per bushel) to get bushels per acre. To be even more conservative and assume poorer grain fill, divide by a larger number such as 95. If you think grain fill has been exceptional and that kernels are larger than normal, consider dividing by a lower number such as 85.

When pulling back husks, one may find poor tip fill (Figure 1). This can be caused by poor pollination and kernel abortion. For example, the ovules may not have been pollinated due to silk clipping by insects, delayed silk emergence, silk deterioration due to heat or drought stress, or a lack of viable pollen due to the same heat or drought stress. Kernel abortion can be caused by stress resulting from heat, drought, or severe nutrient deficiencies (Nielsen, 2003). Tip fill correlates with plant population (Figure 1), and the optimum plant population will typically have about one inch of poor tip fill (Lauer,2006), as grain yield is a balance between plants per acre and kernels per ear.

Figure 1. Reduced tip fill associated with increased moisture stress at higher plant populations.

Photo by Jeff Coulter.

Crop Maturity and Early Frost:

The USDA crop report on September 14 showed 56% of Minnesota corn to be in the dent stage, compared with 78% last year (USDA-NASS, 2009). Kernel moisture at the onset of denting is around 59%, and it generally takes about an additional 25 days from the start of denting to reach physiological maturity (black layer). A light frost killing only the leaves at the half milkline stage can be expected to reduce final grain yield by 5%, while a hard frost killing the whole plant at this same stage would reduce final grain yield by about 10% (Coulter, 2008). Average long-term dates of critical fall temperatures for various locations in Minnesota are listed in Table 1.  

Table 1. Median dates of critical fall temperatures (1948-2005).

Source: http://climate.umn.edu/text/historical/frost.txt

Hybrid Selection:

Remember that no matter what happens this fall, now is the time to be thinking about next year. When selecting hybrids, spread your risk by planting multiple hybrids of differing maturity. The key is to identify and select those hybrids which are consistently top performers over multiple sites or years within a region. The importance of consistency over multiple environments is critical, since we cannot predict next year's growing conditions.

Hybrid selection should be based on information from numerous sources, including universities, grower associations, seed companies, and on-farm strip trials. Past hybrid trials are available from the University of Minnesota at http://www.extension.umn.edu/Corn/trials.html and the Minnesota Corn Growers Association at http://136.162.254.59/mcga/reports/varietyPlotResults.html. Results from this year's trials will be posted soon after harvest.  When in the combine this fall, watch that freshly calibrated yield monitor and start thinking about hybrids for next spring. Success next year begins with decisions made this fall.

Cool weather and low rainfall have held the soybean crop back in parts of Minnesota this summer. Now, significant diseases are a concern in some areas. Several diseases have started to appear recently that can significantly damage soybeans, especially sudden death syndrome (SDS), brown stem rot (BSR), and white mold. These diseases are favored by weather conditions that have occurred in large areas of Minnesota this season. The information we gather now can help to explain why yield may be low in some fields and can assist with targeting disease management where these diseases occur most often. There are no effective fungicide or other treatments that can be used this season to reduce damage from these diseases.

SDS has been reported at significant levels in Dodge, McLeod, and Waseca counties, and it is undoubtedly also appearing in other areas in Minnesota. Based on results from previous years, SDS probably occurs across much of the southern half of Minnesota, but it could occur anywhere in the state. Foliar symptoms of SDS have been developing for at least the past two weeks. The last two weeks of August and the first week of September is a good time to scout for SDS. Look for this disease first in low or compacted areas of fields and near field entry points. Initial symptoms are yellow areas on leaves, and these yellow areas turn into brown patches. Reports have indicated different levels of disease severity among some varieties. This would be a good time to look for different factors that could affect SDS severity, including soybean variety, tillage, drainage, crop rotation, and planting date. The map of the confirmed distribution for SDS in Minnesota, as well as more information and photos for SDS and other soybean diseases, can be found at the Minnesota Crop Diseases web site (www.extension.umn.edu/cropdiseases/soybean/index.html).

Foliar and stem symptoms of BSR are also starting to appear. BSR occurs in fields throughout Minnesota, including all areas where SDS occurs. When scouting fields or attempting to diagnose whether plants are infected with SDS or BSR, keep in mind that the foliar symptoms can look very similar for these two diseases. The key for BSR is to split the bottom 6" of the soybean stems and look for brown pith, especially at the nodes. Plants with BSR will have brown pith, but plants with SDS will have white pith. Keep in mind that plants with BSR always develops brown pith, but foliar symptoms (brown tissue between veins) do not always develop. The only way to know how much BSR is in a field is to split stems, and internal BSR stem infections alone can cause yield loss. BSR tends to be more severe when temperatures are cool (60- 80°F) during reproductive growth stages. When leaf symptoms develop, they can be most severe when soil has been wet at early flowering to pod fill growth stages and dry during maturation. The conditions in large areas of Minnesota appear to have been favorable for BSR this season.

White mold may also be significant in some parts of Minnesota based on growing conditions this year. We have had reports of white mold damaging and killing in several areas of Minnesota. This disease is favored by cool temperatures and rainfall from mid- July through August. All of Minnesota has had cool conditions, and the areas that received enough rain to maintain wet soil for short periods in July and early August are set to develop white mold. Look for scattered and patches of dead and dying plants, and the presence of white moldy growth and sclerotia (black to gray round to oblong structures up to 1/4") on and inside the stems. As with the other diseases, look to see if you can associate the more severe areas with factors that may affect white mold such as soybean variety, manure or fertility history, tillage, row spacing, or high plant population.

Finally, downy mildew is common in a number of areas. Although this soybean leaf disease rarely if ever reaches levels that damages yields in Minnesota, it can be fairly easy to see. Downy mildew typically only infects leaves at this time of the season, although later it can infect pods. Symptoms of downy mildew on the tops of leaves are irregular yellow to brown spots, and the bottom of the leaves under the spots have tan to gray tufts of fungal growth that can be seen easily with a hand-lens.

]]> tag:blog.lib.umn.edu,2009:/efans/cropnews//9997.188814 2009-08-25T17:07:15Z 2009-09-04T20:00:55Z

Is glyphosate less effective in your fields than 10 years ago? Can you recognize the presence of glyphosate-resistant weeds in a field? Wednesday, September 9 ----- Plummer, MN Meet at and depart from Plummer Co-op Creamery (Cenex Station) 1 pm Thursday, September 10 ----- Hawley, MN Meet at and depart from RDO Equipment 9:30 am

Phillip Glogoza Wednesday, September 9 ----- Plummer, MN

Meet at and depart from Plummer Co-op Creamery
(Cenex Station) 1 pm

Thursday, September 10 ----- Hawley, MN
Meet at and depart from RDO Equipment 9:30 am

Is glyphosate less effective than 10 years ago?

Can you recognize the presence of glyphosate-resistant weeds in a field?

]]> If you are unsure, plan to attend one of the field tours that will be held at Plummer and Hawley, Minnesota on September 9 and 10, 2009. Glyphosate resistance develops over time in a field.

Early recognition of the symptomology of surviving plants and patterns within a field will allow more effective management of glyphosate on your farm or the fields you manage. Field tours will be held at Plummer and Hawley to show you how to recognize resistance symptomology and plan strategies for managing resistance.

Farmers, consultants, and agribusiness employees are welcome to attend.

To help us plan better for the day's events, call in and let us know you will be there

for Plummer contact Carlyle Holen at 218-281-8691 or send an e-mail

for Hawley, contact Phillip Glogoza at 218-236-2008 or send and e-mail

]]> tag:blog.lib.umn.edu,2009:/efans/cropnews//9997.188810 2009-08-25T16:59:45Z 2009-08-25T17:26:35Z

Friday, August 28, 2009 10:30 a.m. Dan Dreyer Farm - Ottertail City Tour Agenda: Forage Production and Management Update Forage Insects Past, Present, and Future Alfalfa/Grass Stand Management Hybrid Evaluation and Industry Update From Seed Companies...

Phillip Glogoza

Friday, August 28, 2009
10:30 a.m.
Dan Dreyer Farm - Ottertail City

Tour Agenda:
Forage Production and Management Update
Forage Insects Past, Present, and Future
Alfalfa/Grass Stand Management
Hybrid Evaluation and Industry Update From Seed Companies

]]>
Presenters:
Dr. Paul Peterson, U of MN Extension Forage Specialist
Dr. Phil Glogoza, U of MN Extension Educator
District Sales Managers

Directions
The site is north of Ottertail City. From Ottertail City go east on MN Hwy 108, on the east edge of town turn left onto Buchanan Rd. Head north on Buchanan Rd. for 1 mile, and take a left onto Hilltop Rd. The plot is on the north side of Hilltop Rd. and the west side of Buchanan Rd.

Meal
A noon meal will be provided along with refreshments.
Supported by the companies involved with the research.

Sponsored By:
University of Minnesota Extension

This is a rain or shine event with the entire program shifting to the
Dan Dreyer farm with unfavorable weather.

For more information please contact Doug Holen at the
Fergus Falls Regional Office at (218) 998 5787.

]]> tag:blog.lib.umn.edu,2009:/efans/cropnews//9997.188519 2009-08-21T18:33:00Z 2009-08-21T18:37:32Z

The continued wet weather and harvest delays are increasing the potential for preharvest sprouting. Once the dormancy of the seed is broken and sprouting is initiated the quality of the grain deteriorates, grain elevators will check for this decline in...

Jochum Wiersma The continued wet weather and harvest delays are increasing the potential for preharvest sprouting. Once the dormancy of the seed is broken and sprouting is initiated the quality of the grain deteriorates, grain elevators will check for this decline in quality using the Hagberg Falling Numbers test. The HRSW that are ranked moderately susceptible to pre-harvest sprouting are listed in Table 1. Understand that the potential for preharvest sprouting increases if you swath the grain or if you leave it stand too long while waiting for the grain to reach 13% moisture, all the while rain and heavy dews are forecasted. Rather, harvest the grain as quickly as possible and as soon as moisture content approaches 15% as HRSW can be readily stored up to three months at that moisture content.

Table 1 - HRSW varieties with a higher risk of preharvest sprouting

Variety Preharvest Sprouting Rating*

Bigg Red 4
Blade 5
Granger 4
Hat Trick 4
Sabin 4
Samson 4
Traverse 4

* 1=best, 9=worst

]]> tag:blog.lib.umn.edu,2009:/efans/cropnews//9997.188370 2009-08-20T00:49:58Z 2009-08-20T01:03:06Z

With the majority of the Minnesota corn crop in the milk stage, now is a great time to begin planning for corn silage harvest. Proper harvest management is critical for high quality silage, and it starts with harvest timing. This ensures that the harvested crop is at the optimum moisture for packing and fermentation.

coult077 By Jeff Coulter, Extension Corn Agronomist

With the majority of the Minnesota corn crop in the milk stage (Figures 1 and 2), now is a great time to begin planning for corn silage harvest. Proper harvest management is critical for high quality silage, and it starts with harvest timing. This ensures that the harvested crop is at the optimum moisture for packing and fermentation. Silage that is too wet may not ferment properly and can lose nutrients through seepage. If silage is too dry when harvested, it has lower digestibility because of harder kernels and more lignified stover. In addition, dry silage does not pack as well, thus increasing the potential for air pockets and mold. 

Figure 1. Corn in the milk (R3) stage.

 

Optimum silage moisture at harvest ranges from 50-60% for upright oxygen limiting silos, 60-65% for upright stave silos, 60-70% for bags, and 65-70% for bunkers (Lauer, 2003). Due to variability among hybrids and growing conditions, it is necessary to measure silage moisture using a commercial forage moisture tester or microwave oven rather than simply estimating it from the kernel milkline. Instead, kernel milkline should be an indicator of when to collect the first silage samples for moisture testing. A general guideline is to begin moisture testing when the milkline is 25% of the way down the kernel for horizontal silos, and 40% of the way down the kernel for vertical silos. Then, assume a constant drydown rate of approximately 0.6% per day, and measure moisture again prior to harvest (Roth, 2003).

 

Length of cut and crop processing are also important for obtaining high-quality corn silage. This is because breakage of cobs and kernels increases surface area, which improves digestibility, reduces cob sorting, and results in higher density silage that packs better. Although crop processors are expensive, the higher-quality silage that they produce can increase milk production by 300 pounds per cow per year (Schroeder, 2004). The benefit to crop processors is greatest when there are harder kernels resulting from delayed harvest or drought. When using a crop processor, chopper cut length can be increased, thereby reducing horsepower requirements while maintaining optimum particle size. For example, ideal chop length is 0.375 inch theoretical length of cut for unprocessed corn (Schuler, 2000). For processed corn, recommended settings are and 0.75 inch theoretical length of cut with 0.08 to 0.12 inch roll clearance.

 

A 4 to 6 inch cutting height is generally recommended for corn silage, as it maximizes silage yield and milk per acre. However, drought-stressed corn can accumulate nitrate in the lower part of the stalk, thus increasing the potential for nitrate poisoning, particularly in older livestock on lower-energy rations. The potential for high-nitrate silage can be even worse if drought-stressed silage is harvested within 10 days of rainfall, since rainfall increases crop uptake of soil nitrogen.

 

Silage with high nitrate levels can be managed by dilution with other sources of feed or by increasing the cutting height to 12 inches. Silage cut at this higher height has been shown to have 8% less silage yield and 2% less milk per acre (Lauer, 2003). This same study found that a cutting height of 18 inches resulted in 15% lower silage yield, 12% higher milk per ton, and 4% lower milk per acre when compared to a 6 inch cutting height. Increased silage quality with high cutting is due to a higher ratio of grain to stover. However, corn stalks are a good source of fiber and the lower tonnage with high-chop silage typically makes it hard to justify in the absence of high nitrate levels.

 

When harvest begins, fill silos rapidly to reduce exposure of silage to oxygen and to reduce fungal growth. For bunker silos, pack silage as tightly as possible in progressive wedges in depths of 6 inches or less. 

Figure 2. Corn in the milk (R3) stage.

]]> tag:blog.lib.umn.edu,2009:/efans/cropnews//9997.188020 2009-08-14T18:15:48Z 2009-08-14T18:33:47Z

by Phillip Glogoza, Extension Educator, Crops Management decisions on whether to treat soybean aphids will be affected by the soybean growth stage in a field during the next two weeks. As plants progress to the later reproductive stages (e.g., R5,...

Phillip Glogoza by Phillip Glogoza, Extension Educator, Crops

Management decisions on whether to treat soybean aphids will be affected by the soybean growth stage in a field during the next two weeks. As plants progress to the later reproductive stages (e.g., R5, R6, R7, etc.) risk of yield loss from aphids declines. Currently, the soybean crop ranges from R3 to R5. Insecticide treatments for R5 stage soybeans may respond positively to soybean aphid treatments when populations exceed threshold, however the level of the yield response is less predictable. Early R5 treatments are more likely to realize a positive response than late R5 treatments. Treatments for aphids are generally not recommended beyond the R6 growth stage.

]]> Here is a handout (Adobe *PDF format) that will help identify the appropriate growth stages as the crop develops throughout the region.

Soybean_R_Growth_Stages.pdf

]]> tag:blog.lib.umn.edu,2009:/efans/cropnews//9997.187887 2009-08-12T15:36:17Z 2009-08-12T17:20:41Z

There are two methods of pre-harvest management for wheat that can speed up harvest. Swathing or windrowing is one method. An application of glyphosate is a second option. Several brands of glyphosate are labeled for preharvest weed control. Research has shown that glyphosate can also quicken the dry down of the wheat crop if conditions for dry down are adverse. The preharvest interval for preharvest glyphosate is seven days and expects only to gain a couple of days at the most. More time can be gained with swathing.

Jochum Wiersma There are two methods of pre-harvest management for wheat that can speed up harvest. Swathing or windrowing is one method. An application of glyphosate is a second option. Several brands of glyphosate are labeled for preharvest weed control. Research has shown that glyphosate can also quicken the dry down of the wheat crop if conditions for dry down are adverse. The preharvest interval for preharvest glyphosate is seven days and expects only to gain a couple of days at the most. More time can be gained with swathing.

The optimum time for either pre-harvest management tool is right at or just after physiological maturity of the crop. At physiological maturity, the crop has the maximum kernel dry weight and no additional dry matter will be deposited in the grain. The kernel moisture percentage at physiological maturity is relatively high and can vary from 20 to 40%. Research has shown that swathing just before physiological maturity does not harm the grain yield or quality. This practice, however, is not recommended when using glyphosate as a pre-harvest tool.

There are two visual indicators that can be used to determine whether the crop has reached physiological maturity. The first indicator is the loss of green in the kernel and the appearance of a dark layer of cells or pigment strand along the crease of the wheat kernel (Photos 1). Kernels in the same spike will reach physiological maturity at different times with the middle of the head maturing first.

Photo 1 - Wheat kernels before (above) and at (below) physiological maturity.

Another visual indicator is the loss of green from the peduncle and glumes. If the peduncle just below the head becomes straw-colored, transportation of water and nutrients to the head has been cut off and the crop has reached physiological maturity (Photo 2). The advantages and disadvantages of pre-harvest glyphosate and swathing are listed in Table 1.

Photo 2 - Wheat spikes before (left) and at (right) physiological maturity

Table 1 - Advantages and disadvantages of different methods of pre-harvest management.

]]>