September 2, 2004
In this issue
§ Frost on corn for silage
§ Harvesting immature corn for silage
§ Perennial and biennial broadleaf weed control in the fall
§ Precautions for preharvest treatments in dry edible beans
§ National FSA American Indian Credit Outreach Initiative
§ Thumb Regional Report
§ First freezing temperatures of the fall season
§ Weather news
This week, the Field Crop CAT Alert contains information on harvesting. The Field Crop CAT Alert team is watching the situation closely and may have a special alert in coming weeks to get more information out to readers. Please stay tuned to the CAT Alert over the next few weeks so you don’t miss important information.
This year’s corn crop has been significantly behind in maturity when compared to previous years. Because of this, there is concern about a frost occurring before the corn crop is fully dented and what affect this will have on corn silage.
An early September frost may stop all plant growth/maturity activity but the crop can still make good corn silage. The key in harvesting corn for silage is the dry matter content of the silage. Freezing of the corn will cause rapid drying and farmers will need to monitor the dry matter of the corn and start harvest when the corn reaches 30% dry matter. Frosted corn doesn’t need to be chopped immediately after a frost as it may require additional time to dry to 30% dry matter. However, if the corn is near 30% dry matter when a frost occurs and then followed by dry, windy days, the plant may very rapidly dry down and the corn silage will become too dry for good fermentation.
§ Frost will not adversely affect the quality of corn silage.
§ Harvest corn for silage when it reaches 30% dry matter; the dry matter range for corn silage is 30-45%.
§ Don’t harvest below 30% dry matter just because it was frosted. Wet silage undergoes extensive fermentation and yields poor quality and unpalatable silage.
Much of the corn harvested for silage in Michigan this year may be immature at harvest because of delayed planting and a cooler growing season. Although silage from immature corn can be an excellent forage, certain factors related to harvesting and feeding should be considered.
Immature corn is considerably wetter than normal and seepage from the silo will be extensive if harvested too wet. In addition, very wet corn silage may reduce dry matter intake if it is included in the diet at high levels. Moisture content should be less than 72% when stored in bunker silos and less than 65% when stored in upright silos. This is likely to require harvesting after a frost, particularly for corn planted in late June or early July. The best way to determine when to harvest is to harvest a representative sample of each field (not border rows) and determine the moisture content using a microwave or forced air drier. Do not decide when to harvest by just looking at the corn; leaves dry quickly and turn brown following a frost and then corn appears to be drier than it really is. Leaves are a small fraction (less than 15%) of the entire plant and the plant may still be too wet when the leaves are brown and dry.
Immature corn should ensile will if harvested at the appropriate moisture content. There will be a more than adequate supply of sugars for the microbes to ferment because less sugar has been translocated to the ear and converted to starch. Avoid treating corn forage that is greater than 70% moisture with anhydrous ammonia as it might encourage growth of undesirable organisms resulting in a poor fermentation. Inoculants shouldn’t be necessary if the corn is harvested during warm weather but should be considered for corn forage harvested during cool weather late in the season. If the daily high temperature is less than 55 to 60°F for several days prior to harvest, inoculants should be considered because the naturally occurring microbes which are desirable may be low in number.
Chopping coarsely will increase the effectiveness of fiber at stimulating chewing and salivary buffer flow into the rumen. Immature corn forage can be chopped more coarsely than mature corn for silage because the ears are much less developed and kernels, if present, are soft and do not need to be ruptured during harvest to be digested. Cob disks will also be less of a problem with immature ears.
The feeding value of silage from immature corn depends partly on the degree of maturity at harvest. In general, it will have higher fiber, slightly higher protein, and slightly lower energy content than normal corn silage. The fiber content may exceed 55% NDF for very immature corn silage or for wet corn silage that has had extensive seepage. Digestibility might be 10 to 15% lower for very immature corn silage because of the higher fiber content and diets based on these forages must be adjusted with higher concentrate levels.
Silage from corn that is only slightly immature may have fiber levels that are close to normal even though the grain content may be considerably lower. This is because grain filling occurs by translocating sugars from the stover and the total sugar plus starch content of the plant may change little during grain filling. Slightly immature corn silage has similar or even higher digestibility than mature corn silage. This is because digestibility of starch and fiber decreases as the corn plant matures. Although the grain content increases, the grain becomes harder and more kernels pass through the cow undigested. The non-structural carbohydrates of immature corn are highly digestible sugars and starch. The digestibility of fiber decreases as the corn plant matures giving an advantage to immature silage. Although silage from immature corn may require more grain in the diet than normal, if it is harvested at the appropriate moisture content, it might improve milk production because of higher starch and fiber digestibility.
Wheat fields offer an excellent opportunity to control perennial and biennial broadleaf weeds with fall-applied herbicides. Perennial and biennial broadleaf weeds are best controlled in the fall as they move sugars and carbohydrates from their leaves to their underground storage structures. As a result, a greater amount of a systemic herbicide such as glyphosate will move with the sugars and carbohydrates to underground structures where they can potentially kill the plant.
The ideal timing for fall herbicide application is generally when the perennial or biennial weeds have reached the bud to flowering stage, but before the plants are damaged by frost. Weeds vary in their sensitivity to frost; therefore, the application window is smaller for some species than for others. For example, perennials such as Canada thistle and dandelion survive light frosts and are most effectively controlled when the herbicides are applied through late October and early November. Perennials such as hemp dogbane and common milkweed will complete their life cycles by late summer and do not tolerate frost well, so herbicide applications cannot be delayed until late fall.
For fall applications of Banvel refer to the label for rotation crop restrictions. Table 1 contains a list of recommended herbicides for controlling common perennial and biennial broadleaf weeds with fall herbicide applications. Table 2 provides the glyphosate product application rate in fl oz/A based upon glyphosate formulation and rate in lbs ae/A as found in Table 1. Always add ammonium sulfate (AMS) at 17 lbs/100 gal of spray solution to all treatments containing glyphosate.
Recently, three Roundup (glyphosate) brand products received supplemental labeling for preharvest and spot treatment of weeds in dry beans. These products are Roundup WeatherMax (22 fl oz/A), Roundup UltraMax (26 fl oz/A), and Roundup OriginalMax (22 fl oz/A). Applications of these products are intended to be used to control weeds that may hinder harvest. DO NOT use these products for vine dessication, as residues of glyphosate have been found in harvested beans if applications are made too early. For preharvest purposes only, glyphosate should be applied when beans are in the hard dough stage (30% moisture or less). Applications of glyphosate should also be made seven days before harvest and only one application should be made per year. DO NOT apply glyphosate to beans grown for seed, and DO NOT feed treated vines and hay from these crops to livestock. If a vine dessication treatment is needed paraquat (Gramoxone Max) should be used. Details for this type of application can be found in Table 5B of the 2004 Weed Control Guide for Field Crops.
Are you an American Indian farmer, rancher, or youth (10-20 years) searching for financing for an agricultural business or project? If yes, the National FSA American Indian Credit Outreach Initiative (ICOI) can help. Teresa Magnuson is the ICOI’s Outreach Liaison for Michigan and Indiana and has the honor of assisting tribal people secure the financing necessary to fulfill their agricultural business needs and dreams.
The National FSA American Indian Credit Outreach Initiative Program stems from an innovative cooperative agreement with the National Tribal Development Association and the USDA’s Farm Service Agency. The ICOI is a creative approach designed to address the unique agriculture credit needs of the American Indian community. The project incorporates outreach, education, and loan application preparation services to ensure American Indian farmers, ranchers, and youth have access to the full range of FSA credit opportunities.
If you are interested in learning more about the National FSA American Indian Credit Outreach Initiative or would like to schedule a presentation for your organization or department, please contact Teresa Magnuson, 4470 Cricket Ridge Dr. Apt. 202, Holt, MI 48842, phone: (517) 694-7784, teresa@indiancreditoutreach.com
Temperatures in the high 70’s and 80’s have been a welcome change. Rainfall over the past week was somewhat variable but most areas received at least 1.5 inches of rain. This is too late for some crops but will sure help most.
In sugar beets, cercospera leafspot continues to develop but the September calendar has some growers evaluating how much longer we will need chemical protection. This beet crop shows good yield potential that we don’t want to lose to a controllable disease.
Corn is making the most of the recent accumulation of GDD’s. Corn maturity is variable with some of the early corn showing the milk line advancing nicely while others are still in the full milk stage.
The recent rain and increased temperatures shows some promise for soybeans as well as corn. There are a lot of small (0.5 to 1 inch) pods on the top of plants that are going to need a perfect finish to the growing season to make an impact on yield.
Dry bean maturity is progressing nicely in most fields. There are a few exceptions of later planted and later maturing beans that are very green yet. These late fields appear to have great potential if we can get enough time for natural plant death and dry down.
With some crops lagging far behind normal phenologically, the date of first freeze may be a major factor in determining final yields as well as grain quality this fall. Unfortunately, from a meteorological perspective, there is no reliable way to forecast these events more than a few days in advance. First fall freeze events (and last freeze events of the spring season) are the result of a complex mix of large, synoptic-scale and local, micro-scale factors. The best strategy for prediction is simple: a knowledge of the climatological statistics of a given area, and consistent monitoring of the 6-10 day outlooks for future movement of large, Canadian-origin high pressure air masses into the region. At this time of the year, frost and freezing temperatures are not possible without clear, calm conditions and low dew point temperatures (all of which tend to be associated the air masses mentioned above).
In the 6-10 day outlooks, look carefully for forecasts of below normal or much below normal temperatures in the Great Lakes region as well as a northerly or northwesterly configuration of the jet stream (i.e. from northern Canada southward into the central U.S.). Also, freezing temperatures tend to occur more easily in low-lying areas where cold air draining off surrounding topography can collect or “pond,” and on dry, well-drained soils in which the air in the soil pore spaces acts as an insulator and reduces the amount of heat energy stored in the soil profile from reaching the surface.
From a climatological perspective, Figures 1A, B, and C give the average (50th percentile), 10th percentile, and 90th percentile date of first fall freezing temperatures (32°F or lower at the 5-foot instrument shelter height), respectively. The 10th percentile dates refer to the earliest 10 percent of observed first freeze events while the 90th percentile refers to the date at which 90% of all first freezes have occurred. With the first and last of these dates for a given location, one could determine a representative range of first freeze dates, from the 10th percentile to the 90th percentile, which statistically comprises 80 percent of all possible events in the period of record. Surprisingly, at most locations, this range of dates is only about three or four weeks. For example, at Lansing the figure indicates the average first freeze date to be about October 5, and in 1 out of 10 years it is as early as September 22 (the 10th percentile) and as late as October 17 (the 90th percentile). It is important to note that these statistics refer to temperatures taken at a 5-foot level inside an instrument enclosure. Actual temperatures near the surface may be several degrees colder, especially under clear, calm, stratified conditions, even though the 5-foot shelter/enclosure temperature is still above freezing. Geographically, the average date of first fall freeze in Michigan depends greatly on proximity to the lakes, with several weeks separating the earliest occurring events in interior sections of the Upper and Lower Peninsulas to the latest events at stations right along the lakeshore in the south.
Major changes in the jet stream orientation across North America took place last week, with the formation of a trough across western sections of the continent and a broad ridge across the east leading to above normal temperatures and widespread rainfall across Michigan through last weekend. This week, the jet stream pattern remains similar with the upper air ridge and low level high pressure leading to mostly warm and dry weather conditions. The passage of a weak frontal boundary through the state and the movement of more humid air into the region from the southwest will lead to the chance of a few scattered showers or thundershowers during the next couple of days, although most areas of the state will remain dry into the weekend. Temperatures will remain at above normal levels through the end of the weekend with slightly cooler weather early next week. Look for highs to generally range from the upper 70's north to the mid 80's south statewide with low temperatures from the mid 50's to mid 60's. Next week, significant rainfall is possible across the state and region depending on the exact track of Hurricane Frances, which is expected to make landfall as a powerful category 4 or greater hurricane somewhere along the southeast coast of the U.S. early in the weekend. One forecast scenario includes the possibility of the remnants of this storm could combine with another weather system moving eastward out of the Great Plains by the middle of next week with the potential for a significant rainfall event somewhere in the Upper Midwest. Remember that tropical weather systems are inherently difficult to forecast, especially several days in advance, so the potential for such an event may change with time.
Further upper air changes are expected during the next one to two weeks with a fast, zonal (west to east) pattern suggested by the medium range forecast models. The NOAA CPC 6-10 day outlook for September 7-11 calls for near normal temperatures statewide and for precipitation to range from near normal in western sections to above normal in the east. In the 8-14 day time frame covering September 9-15, the outlook calls for above normal precipitation totals statewide and for temperatures to range from near normal in northern sections to below normal in the south. Unfortunately, because of major differences between some of the forecast tools used to create the outlook in the 8-14 day time frame, forecaster confidence is considered much lower than normal.
