C.O.R.N. Newsletter 2013-34

Dates Covered: 
October 8, 2013 - October 15, 2013
Editor: 
Adam Shepard

Corn drydown – What to expect?

Recent wet, cool weather slowed drydown.  By early to mid‑October, dry-down rates will usually drop to ½ to 3/4% per day (from rates of up to 1% per day in September when drying conditions are usually more favorable). By late October to early November, field dry‑down rates will usually drop to 1/4 to 1/2% per day and by mid November, probably 0 to 1/4% per day. By late November, drying rates will be negligible.

Estimating dry‑down rates can also be considered in terms of Growing Degree Days (GDDs). Generally, it takes 30 GDDs 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 October, we accumulate about 5 to 10 GDDs per day. However, note that the above estimates are based on generalizations, and it is likely that some hybrids vary from this pattern of drydown.

Past Ohio research evaluating corn drydown provides insight on effects of weather conditions on grain drying. During a warm, dry fall, grain moisture loss per day ranged from 0.76 to 0.92%. During a cool, wet fall, grain moisture loss per day ranged from 0.32 to 0.35%. Grain moisture losses based on GDDs ranged from 24 to 29 GDDs per percentage point of moisture (i.e., a loss of one percentage point of grain moisture per 24 to 29 GDDs) under warm dry fall conditions, whereas under cool wet fall conditions, moisture loss ranged from 20 to 22 GDDs. The number of GDDs associated with grain moisture loss was lower under cool, wet conditions than under warm, dry conditions.

Agronomists generally recommend that harvesting corn for dry grain storage should begin at about 24 to 25% grain moisture. Allowing corn to field dry below 20% risks yield losses from stalk lodging, ear rots, insect feeding and wildlife damage. This year growers should be prepared for localized root lodging and stalk lodging that may slow harvest and contribute to yield losses.

Cereal Rye – A Cover Crop with Feed Value?

In recent years, rye (Secale cereale L.), also known as cereal rye or winter rye, has been planted by producers as an entry level or “user friendly” cover crop.  As a cover crop, it is a great nutrient recycler, soil builder, topsoil loosener, and erosion preventer.  For dairy and beef producers, rye can also be considered for additional grazing or forage value.  Based on surveys from several Northwest Ohio producers who have used rye as a spring feed source, it can provide additional feed tonnage on idle acres in a corn-soybeans rotation and with minimal effort or expense. 

According to the Ohio Agronomy Guide, rye is most winter hardy and earliest maturing cereal grain grown in Ohio. While spring rye-lage will not have the same feed value as corn silage, producers can evaluate its cost per pound of gain to see if it may fit in their total mixed ration (TMR) feeding systems.  Based on feed analyses from five producers, the ranges for some key feed quality indicators on a dry basis were: yield of 2-3 T/ac, harvested at dry matters (DM) of 21-32% (avg. 27%), crude protein 8-18% (avg. 12.7%), total digestible nutrients (TDN) 53-63% (avg. 60.4%), net energy for gain of .24-.38 mcal/lb (avg. .34 mcal/lb), net energy for lactation of .54-.67 mcal/lb (avg. .63 mcal/lb), and relative feed value (RFV) of 71-121 (avg. 102).  These analyses were from rye harvested the start of the boot stage all the way to full head, thus range in quality varies.

How do you produce rye for rye-lage?  Since many producers no-till soybeans and the planting window for soybeans is a little later, consider planting rye after silage corn or early harvested corn that is going to no-till soybeans in the spring.  This timeframe fits well into many cover crop programs and one of the advantages of rye is that it will germinate up to November 1st on normal years.

As with all of our crops, starting with a clean seedbed is very important.  Fields with a history of winter annuals (i.e., marestail) need to have a cleanly tilled seedbed or follow Dr. Mark Loux’s “Burndown Suggestions for No-tillage Wheat” (C.O.R.N. 2013-30, Sept. 10-17, 2013).  Rye planted for forage production should be drilled at a rate of 85-115 lbs/acre (more than typical cover cropping rates) and ideally planted by October 20th.  Fertility for high production rye is similar to wheat and starter fertilizer should be applied according to soil test results and the Tri-State Fertility Guide (see “Important Wheat Management Guidelines”, Lentz et al. C.O.R.N. 2013-30, Sept. 10-17, 2013).  Producers should be sure to account for full crop and stover removal and consider fertilizing for the subsequent soybean crop.  In livestock situations, manure may be incorporated in the fall in place of starter fertilizer.   Of course, if you are just trying to scavenge nutrients, level of starter fertilizer use is up to the producer.  In the spring, up to 50 lbs/acre of nitrogen can be top-dressed to increase production before termination. 

Mowing of rye at boot stage (mid-May) is most ideal for tonnage, feed quality, and palatability.  Harvesting at this time reduces some of the concerns with rye limiting soil moisture and nitrogen to subsequent crops.  Mowing can be done with a disk-bine or haybine, but drying can be a challenge.  A chopper with a pick up head can be used to harvest the rye-lage at 25-30% DM (upper end of range preferred; low DM can result in excessive seepage and undesirable fermentation).   Cut length should be adjusted to .75-1 inch for best results. Rye-lage should be packed and covered similar to corn silage to maintain its quality.  After rye harvest, soybeans can still be planted and normal yields realized. 

(Sources: Ohio Agronomy Guide-14th Edition, Midwest Cover Crops Field Guide; 2013 Ohio & Indiana Weed Control Guide-Bulletin 789)

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About the C.O.R.N. Newsletter

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.