|
|
|
In This Issue:
A) Early Soybean Harvest Provides Opportunity for Wheat
B) Just What Is a Hessian Fly?
C) Check Soybean Grain Moisture
D) Corn Harvest Losses and Grain Dry down Rates
E) Flat Structures & Upright Silos for On-farm
Grain Storage
F) Aeration Technology for Moisture Management
The early harvesting of soybeans this year has provided Ohio farmers with an opportunity to plant wheat in a very timely fashion. One of the keys to top yields is planting the wheat early enough so plants develop several tillers before winter dormancy. However, wheat should not be planted too early because of severe diseases and insect damage associated with warmer weather in mid- September. Hessian fly, aphids carrying barley yellow dwarf virus, powdery mildew, Stagonospora leaf blotch and leaf rust are all problems growers can avoid by planting wheat after the Hessian fly safe date for their county. The Hessian fly safe date for the northern most counties of Ohio is September 22 and October 4 for the southern most counties. Research over many years has shown that the best yields are from fields planted from 5-10 days after the Hessian Fly Safe date for the area.
Planting wheat no-till after soybeans has been very successful in Ohio.
Currently, soil conditions are very dry, so planting depth is very critical.
Do not plant too shallow, one inch planting depth is advised when planting
near the Hessian Fly Safe date. Check planting depth several times during
the planting operation, especially in areas with more soybean residues.
Optimum seeding rates are in the range of 1.6 to 2.1 million seeds per
acre. This would be 22 to 28 seeds per foot of row for 7 inch rows.
Plant varieties that are known to stand well at the higher rate and those
with lodging problems at the lower rate. Plant high quality seed that has
been treated with a seed treatment fungicide. Raxil XT (Gustafson, Inc.)
and Dividend XL (Novartis, Inc.) are two of the leading seed treatments
available for use on wheat. Apply 20-30 lb of nitrogen in the fall to facilitate
early plant development. If a soil test indicates there is less than 80
lb phosphorus per acre, apply fertilizer before planting. Fields to be
planted to wheat should maintain test value of 270, 330 and 370 lb of potassium
per acre with cation exchange capacities of 10, 20 and 30, respectively.
It is frequently valuable to check stand establishment in early November
to see how well the drill operated and if the production system is working.
Make notes as to what you should do differently. You do not have
to worry about the fields again until it is time to assess winter survival
in early March.
The adult Hessian fly, Mayetiola destructor (Say), is a small fly, sooty black in color. It is smaller than the common mosquito. Reddish colored eggs are laid in lines of ten to twelve in grooves on the upper side of leaves. The larvae are white legless maggots, they work their way down the leaves and feed behind the leaf sheath.
The Hessian fly passes through 2 generations per year in which adult flies deposit eggs, maggots hatch on the leaves and feed on the stalks, and after feeding the maggots pupate into a form commonly recognized as flaxseeds.
The adults are active in the early spring and late summer. Damage by maggots occurs in the late spring and early fall. As a result, when damage is noted, the flaxseed pupae can often be located near the infested tiller in the spring or associated with broken stems observed in the early summer.
Hessian fly feeding injures the stem and reduces plant vigor. These weak stunted plants may not survive the winter. Plants damaged in the spring may not die but will produce stalks that are spindly and break easily.
If a serious infestation of Hessian fly develops in the field, the problem is generally detected after the damage has been done and the fly is in the flaxseed stage. There are no known rescue treatments.
Prevention of Hessian fly damage has depended on two cultural methods of pest management in recent years, namely: (1) planting varieties resistant to Hessian fly and (2) planting wheat in the fall after the late summer adult egg laying period has passed. Relying only on resistant varieties has proven unsuccessful because of the Hessian fly can adapt by producing new "biotypes". No currently used variety of wheat is resistant to all of these biotypes. Therefore planting after the fly safe date is the best way to reduce the risk of a Hessian fly infestation. By breaking the life cycle of the Hessian fly in the fall you can greatly reduce the damage of any spring generation.
An additional benefit of planting after the "fly safe date" is that it will greatly reduce if not eliminate the risk of infection of Barley yellow dwarf virus in your wheat.
Fly safe dates in Ohio range from September 22nd near Lake Erie and Michigan to October 5th at the southern tip of Ohio. Wheat planted after the fly safe date in the fall will escape the period of egg deposition by the fall brood.
An online map of the fly safe dates for Ohio counties is available at
the following location: http://www.ag.ohio-state.edu/~ipm/images/hf_map.htm
The loss of one "normal" sized ear per 100 feet of row translates into a loss of more than nine bushel/acre. An average harvest loss of 2 kernels per square foot is about 1 bu/acre! Keep in mind that most harvest losses occur at the gathering unit. The following table from an Ohio State study shows the range of visible corn harvesting losses by source.
CORN HARVEST LOSSES BY SOURCE, BU/ACRE
Source
Low Avg.
High
------------------------------------------------
Preharvest
0 .35
2.44
Gathering Ear 0
.50 4.0
Loose kernel .02
.66 3.36
Machine
.13 1.51
5.02
Total crop loss .17
1.86 7.47
------------------------------------------------
From Gliem, J.A., R.G. Holmes, and R.K. Wood. 1989. Current utilization
and optimization of existing machinery technology when harvesting feed
grains. The Farm Income Enhancement Program. OSU Dept. of Agric. Econ.
and Rural Sociology.
Average gathering unit losses accounted for about a 1.2 bu/acre loss out of the total 1.5 bu/acre machine loss. This data indicates that approximately 80% of the total machine loss is caused by corn never getting into the combine.
Corn will normally dry approximately 3/4 to 1% per day during favorable drying weather (sunny and breezy) during the early warmer part of the harvest season from mid-September through mid-October (probably a week to 10 days earlier, respectively, for southern and northern Ohio). By late October to early to mid-November, field dry-down rates will usually drop to probably no more than 1/2% per day in central Ohio. By mid to late November the rate will drop to 1/4% per day and after Thanksgiving, drying rates will be negligible.
Estimating dry-down rates can also be considered in terms of Growing
Degree Days (GDDs). Generally it takes 30 GDD to lower grain moisture each
point from 30% down to 25%. Drying from 25 to 20 percent requires about
45 GDDs per point of moisture. In September we generally average 10-15
GDD per day. In October (as things cool down) the rate drops to 5-10 GDDs
per day. However, note that the above estimates are based on generalizations
and it is likely that some hybrids vary considerably from this pattern
of dry-down.
CONSIDERATIONS
1) Bushels of corn or soybeans to be stored: The standard bushel occupies 1.25 cubic feet. A 100' by 40' flat storage filled to a level depth of 6' holds an estimated 19,200 bushels. If grain is peaked, storage capacity can be increased to 30,848 bushels. An upright silo 20' in diameter filled to a depth of 40' will hold 10,000 bushels.
2) Moisture content of grain being stored: Grain going into flat storage needs to be dry. For corn the moisture should be 14-15% and for soybeans the moisture should be 12.5-13.5%. Storage moisture contents slightly higher (<1%) than these can be tolerated if the operator takes special care in aerating the grain and will be storing the grain only for a few months. If the grain is of poor quality, the lower moisture limits should be followed.
3) Length of storage: Storage time will depend on factors such as need for the structure (i.e., machinery shed for equipment), feeding or marketing schedules/opportunities, risk of spoilage, etc. Generally storage time should be limited to nine months and the preferable duration is 2-6 months.
4) Aeration requirements: Grain also needs to be cooled to ambient conditions before being placed into temporary storages. Cooling the grain will minimize moisture migration during the initial months of storage. If grain is to be stored beyond two months, an aeration system using either a fully perforated floor or a properly designed duct system needs to be in place. Minimum airflow requirements are 1/10 cfm/bu of grain stored for continuous aeration and ½ cfm/bu of grain for fan operation of two days every two weeks (maximum suggested aeration interval).
5) Structural integrity: Temporary structures need to limit moisture addition to the grain from the environment. Dripping water (from the roof or walls) or vapor movement (through a concrete floor, for example) leads to grain spoilage and must be limited as much as reasonably is possible.
6) Structural strength: Building or silo walls may not be designed to handle loads placed on them by grain. For flat structures, this may require limiting the storage depth (minimize piling against walls) or building special bulkheads. For upright silos, the manufacturer needs to be consulted for proper retrofitting procedures.
7) Location/material handling: Getting grain into and out of storage is an important consideration. Auger systems, front-end loaders, and pneumatic conveyors can be used. Some means of unloading stored grain and loading trucks or wagons needs to be provided. Developing and implementing a grain handling system to minimize the time and cost for filling and unloading temporary storages is often a major challenge.
For detailed information, the reader is referred to the following references:
MWPS-13, Grain Drying, Handling & Storage
Handbook
MWPS-29, Dry Grain Aeration Systems Design
Handbook
MWPS-35, Farm & Home Concrete Handbook
These materials can be obtained from your local Extension Office or
by calling 614-292-6007.
Using aeration technology to manage content of a stored grain mass for the purpose of raising its moisture has long been a controversial subject. This paper presents three case examples that demonstrate the technical feasibility and economic incentives for conditioning overly dry corn and soybeans to optimum market moisture content. In each case the economic gain was substantially higher than the electrical costs to operate the fans. For soybeans valued at $7/bu in a 135700 bu tank, the economic gain ranged from 9.8 to 25.8 cents/bu when a site specific conditioning strategy was employed in combination with an automatic fan controller, top down aeration and intermittent unloading. Nevertheless, several precautions need to be considered carefully not the least of which are the ethical and legal implications for adding moisture to grain.
For a complete copy of this paper including technical information, access
the following website at:
http://www.agribiz.com/fbFiles/tNews/grainquality/aeration.htm
Readers can subscribe electronically to this newsletter bysending an
e-mail message to: Past versions of C.O.R.N. can be found on the World Wide Web at: http:/www.ag.ohio-state.edu/~corn/archive/
C.O.R.N. is a summary of crop observations, related information, and
appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N.
is produced by the Ohio State University Extension Agronomy Team, State
Specialists at The Ohio State University and Ohio Agricultural Research
and Development Center. C.O.R.N. Questions are directed to State Specialists,
Extension Associates, and Agents associated with Ohio State University
Extension and the Ohio Agricultural Research and Development Center at
The Ohio State University.
Contributors to C.O.R.N. this week include:
Editor: Clark Hutson Web Editor:
Clark Hutson
Information presented above and where tradenames are used,
they are supplied with the understanding that nodiscrimination is intended
and no endorsement by Ohio State University Extension is implied. Although
every attempt is made to produce information that is complete, timely,
and accurate, the pesticide user bears responsibility of consulting the
pesticide label and adhering to those directions.
All educational programs conducted by Ohio State University
Extension are available to clientele on a nondiscriminatory basis without
regard to race, color, creed, religion, sexual orientation, national origin,
gender, age, disability or Vietnam-era veteran status.
Issued in furtherance of Cooperative Extension work, Acts
of May 8 and June 30, 1914, in cooperation with the U.S. Department of
Agriculture, Keith L. Smith, Director, Ohio State University Extension.
TDD # 1 (800) 589-8292 (Ohio only) or (614) 292-1868
STATE SPECIALISTS: Pat Lipps & Anne Dorrance (Plant Pathology),
and Peter Thomison (Corn Production);
DISTRICT SPECIALISTS: Ed Lentz (Agronomy);
EXTENSION AGENTS: Roger Bender (Shelby), Ray Wells (Ross), Clark Hutson
(Seneca), Barry Ward (Marion), Dennis Baker (Darke) and Greg La Barge (Fulton).
| C.O.R.N. | Newsletter | Archive | Search | Questions? | Ohioline | Publications |