Bt corn is an excellent management tool for corn borer species, both the European and southwestern. One drawback is that producers must anticipate and then actually have a corn borer infestation to gain financially from this technology. To help producers during the winter months ascertain where corn borer are likely to be a problem for the upcoming season we often share two bits of information, over-wintering numbers and highest risk corn.
Most are aware that European corn borer (ECB) numbers have been down over the last several years, the last significant outbreak being in 1996. Purdue’s 2001 ECB over-wintering survey revealed that, except for northwestern counties, the population was rather unimpressive (refer to Pest&Crop #26, October 12, 2001). Since these over-wintering larvae become this year’s threat, ECB aren’t looking too ominous for the 2002 corn crop. This says nothing about larval mortality from tillage and, more importantly, natural pathogens that attack borers in the fall and early spring after the survey is conducted.
Surviving larvae are in the process of pupating and will soon emerge as moths to seek suitable egg laying sites. Fields targeted by this first generation are the tallest, lushest, greenest, corn in an area. Normally, only corn above 18+ inches in extended leaf height is threatened by corn borers. Smaller corn has a substance in the leaves called DIMBOA, a plant aglucone, which acts as a “built-in insecticide.” The moths may lay eggs on the short corn, but larvae will not be able to establish. By the time moths are at their peak flight in early June, they aren’t going to find many fields of corn suitable for survival. On the other hand, the few fields planted before the rains, could be suitable for egg laying. Hindsight being 20/20, these first-planted, “trap crop” fields should have been planted in Bt.
The second or late generation ECB moths are attracted to the late planted/maturing cornfields for egg laying. However, in 2002, 90% of Indiana’s corn will be late planted. This being the case, the moths won’t be limited to certain fields but rather diluting themselves among many late maturing fields. The need for ECB resistance in corn yet to be planted appears low. Therefore, any corn hybrid switching at this time should be with relative maturities in mind, not insects.
This is being written on the one-year anniversary of receiving our first armyworm call during the outbreak of 2001. What a difference a year makes! So far, we’ve NOT had one phone call but let’s not be completely lax. Pest managers should be examining wheat in different areas of a field, especially where plant growth is dense. Look for flag leaf feeding, head feeding, and armyworm droppings (excrement) on the ground. Shake the plants and count the number of armyworm on the ground and under plant debris. On sunny days, the armyworm will take shelter under crop residue or soil clods. If counts average approximately 5 or more per linear foot of row, the worms are less than 1-1/4 inches long, not parasitized or diseased, and leaf feeding is evident, control may be justified. If a significant number of armyworm are present and they are destroying the leaves, or the heads, treat immediately.
Ron Blackwell, IPM Surveyor Specialist, has randomly sampled emerging cornfields in southwestern and west central Indiana counties for black cutworm. Our thanks to Dwain Rule, Midland Co-op, and Betsy Smith, Growers’ Co-op, for serving as “safari” guides on this hunt. Only leaf feeding was found at this time, indicating that the larvae are still small. The larvae that were collected were early fourth instar, which soon will begin cutting. Damage ranged from 0 to 5% of plants damaged, with 0 - 2% being the norm. All fields sampled were considered high risk, that is, many winter annuals were present during moth flights. So far, this is good news concerning this pest! In addition some minor armyworm feeding was observed.
Everybody is well aware of the fact that Indiana has had an over abundance of the water works. In a year like this, where planting may be delayed to the end of May, concerns and questions start to come in on herbicide rotation restrictions. Crop rotation restrictions are in place to limit crop injury the following year due to herbicide persistence and to limit the environmental impact due to seasonal weather patterns. They can range from two years to no waiting period at all. Several things can have an effect on a crop rotation restriction. In no order of importance are, crop the following year, rates used, how the herbicide degrades, and the specific soil characteristics. Some herbicides, such as glyphosate products (Roundup Ultra Max, Glyphomax Plus, Touchdown, etc) and Gramoxone Max (paraquat) have short to no rotational restrictions due to the fact that they both have very little residual activity. Herbicides containing acetochlor (Harness Xtra, Surpass, Topnotch) have long rotation restrictions for small grains (see Table 1). Some herbicides may have different rotation restrictions depending on soil pH. Steadfast (nicosulfuron and rimsulfuron) has a rotation restriction of 10 months to sorghum, but if the soil has a pH greater than 7.5 then it is 18 months. Increasing the rates of Valor (flumioxazin) increased the rotation restrictions of corn, wheat, sorghum, and sunflower from one month to two.
As the days tick by so does that time between application and planting next season. Furthermore, pushing back planting pushes back POST applications. A PRE application of Hornet WDG (10.5 month rotation restriction to soybean) on June 1st means that to comply with the label, a producer can’t plant till April 15th the following season. Accent gold, Harness, Harness Xtra, Hornet WDG, and Stinger all have rotation restrictions to soybean over 10 months. Authority, Canopy XL/SP, Command Xtra, Flexstar, Guantlet, and Reflex all have rotation restrictions to corn of 10 months. However, there are many products in both corn and soybean that have small rotations intervals. In corn, Accent, Basis, 2,4-D, Celebrity Plus, Sencor, and Balance Pro all have rotation restrictions to soybean six or less months. In soybean, Assure II, Domain, Fusilade, Fusion, Pinnacle, Resource, Sonalan, and Valor all have rotation restrictions to corn or four or less months.
Table 1 gives rotation intervals for several of the herbicides used in Indiana. Included are the rotation intervals for field corn, soybean, and wheat. For other rotation restrictions for crops not listed please read specific product labels.
According to the National Agriculture Statistics Service USDA, by the week of May 12th only 11% of corn was planted and 4% had emerged in Indiana. From the same source, Indiana only has 3% of soybean in the field. The weather in Indiana has not been conducive for timely planting this year to say the least. Several weeks of wet cold weather has pushed back field preparation and planting for many. In the realm of weed control, burndowns, PRE, and POST are all likely to be late this year. Resulting in larger more difficult to control weeds. Also, these large weeds will have to be burnt down or removed to limit interference with planting.
Many of the fields already have large weed stands and size will be a factor. Burndown options for corn and soybean include glyphosate products (Roundup Ultra Max, Touchdown, Glyphomax Plus, etc) or Gramoxone Max (paraquat) sometimes with a pint of 2,4-D ester. Increase of weed size will lead to decreased weed control requiring increased rates with some products. Roundup UltraMax rate recommendations are 24 to 48 oz./A to control giant ragweed that is from emergence to 11” tall. Be aware that glyphosate takes from 5 to 14 days to dry down controlled weeds. For the sake of speed, Gramoxone Max (paraquat) may be considered. Gramoxone Max’s label recommends the use of 1.3-1.7 pt./A for 1 - 3” weeds, 1.7 - 2 pt./A for 3 - 6” weeds, and 2 - 2.7 pt./A for 6” weeds. However, this year many of the weeds will be beyond optimum size for control. The use of a disk may be needed to knock down large annuals and return things to a fair playing field. It is not recommended that you plant into a full bed of vegetation. This may interfere with your planter’s efficacy.
If a burndown is applied, many producers might choose to skip the use of a PRE. However, many PRE applications can be applied after planting, but before emergence, possibly opening up a window in areas where it is needed. Several producers may be going to a complete POST program even if they have not done so in the past. The use of a POST applied product with some residual activity or tank mixing a product with some residual is recommended. Atrazine + oil, Basis, Bicep II Magnum, Bullet, Callisto, Dual II Magnum, FulTime, Guardsman Max, Hornet WDG, Pursuit DG, or TopNotch in corn. Aim, Backdraft, Extreme, FirstRate, and Pursuit DG are herbicides that can be applied POST in soybean that have some residual components. See labels for rotation restrictions on specific products.
A good system for this year will be the Roundup Ready system. However, many people may take this stance, if not already planned, and Roundup Ready seed may be in high demand becoming scarce for those that are looking to buy seed this late in the season. Due to the size of weeds, two applications at higher rates may be required (see above). One application of Roundup UltraMax (see specific labels for other glyphosate products) at 32 fl. oz./A then a second application at the same rate at least 14 days later. In the case of Roundup UltraMax, Touchdown, Glyphomax Plus do not apply more than 2.4, 3, 3 qt./A/cropping season, respectively. No matter what is done certain weeds will still be problematic.
Canada thistle is a difficult perennial to control without the fact that these cool wet temperatures are optimum for growth. Many of the herbicides applied in a POST system may only suppress Canada thistle by burning the surface parts. Several applications of contact herbicides can wear down underground root systems or suppress Canada thistle; however, this year it may be difficult enough to get two applications in the field. The use of translocating (herbicides that move through the plant) herbicides are required to control the underground portions. Work done at Purdue University by Dr. Merrill Ross suggested that the optimum time to treat Canada thistle in Indiana with glyphosate is in late may to early June, when the plant is at least 10” tall after flower buds are formed, but before flowers open. More than one application is recommended three to 12 months apart. During the hot dry part of summer, Canada thistle stops growing. At this time, efficacy on controlling the underground root system will be reduced greatly. If at this time it is impossible to apply herbicides or the Canada thistle is past the above point of development, applications can also be made when the fall regrowth occurs in late September and early October.
In corn, combinations of dicamba (Banvel, Clarity, Distinct), 2,4-D (many trade names), Beacon (primisulfuron), and Basagran (bentazone) can suppress Canada thistle. Stinger (clopyralid) is effective on Canada thistle applied at 1/3 to 2/3 pt./A (dependent on infestation) from the rosette to the bud stage. This stage may already be past for much of the Canada thistle in Indiana this year. Also, Stinger has a 10.5 to 18 month rotation restriction into soybean depending on amount of organic matter and rainfall.
Two weeks ago I wrote an article about leaf blotch of wheat. In this article, I discussed a weather-based model for predicting leaf blotch severity, but at the time did not yet have all the weather data required. I ran the model today, and it predicts a severity of 91%. This means that most of the flag leaf and all of the leaves below will be killed prematurely by infections of Septoria tritici and Stagonospora nodorum. This model was developed from data collected at Lafayette, and its applicability to other areas of the state has not been tested rigorously. Most of Indiana has had the persistently wet weather that favors leaf blotch. What makes disease prediction a tough call is the cool nights. At many stations, daily minimum temperatures over the past 3 weeks have dropped below 45°F on several nights. A minimum temperature of 45°F seems to be a lower threshold for the disease.
Scab (aka Fusarium head blight) of wheat is another wet weather disease. Long periods of wet, humid weather while wheat is flowering are conducive to the disease. Wheat in southern Indiana that was flowering during recent rains may have already been infected. Wheat farther north will be at risk if rains move into the state again as the crop reaches the flowering stage. Wheat that is planted into corn residue or near a source of residue is at greater risk, but when weather is very favorable, even wheat at some distance from corn residue can be infected.
If a field intended for corn cannot be planted before late May, a grower may elect to switch to soybeans. Because most of Indiana’s field crop acreage is in a corn-soybean rotation, this will mean a second year of soybeans in a field. Soilborne microorganisms cause several major diseases of soybeans in Indiana, such as soybean cyst nematode, Phytophthora rot, sudden death syndrome, white mold, and brown stem rot. In fields with a history of soybean cyst nematode, sudden death syndrome, or white mold it is particularly important to avoid second year soybeans. A second year of soybeans in a field that has had any of these problems can lead to a much greater problem this year, and problems for many years to come. The pathogens responsible for these diseases build up during a year of soybean production, but will decline somewhat during the “off” year of corn. If soybeans are grown sequentially, this can result in a huge population of the pathogen in the soil. Even though a grower returns to the corn-soybean rotation after 2 years of soybeans, the higher pathogen population may persist for many years.
Seed or seedlings in the few cornfields already planted have been sitting in cool, wet (saturated) soils for 2 or 3 weeks. Stand thinning may occur through the activity of several soilborne fungi that infect sprouting seed or young seedlings. Plants do not need to be in ponded areas for this to occur. Seed infected early in the sprouting process may not produce a seedling. Seedlings infected somewhat later will grow slowly compared to neighboring healthy plants, turn pale green and yellow, and then usually die. Virtually all seed corn is treated with fungicides, but effectiveness of these products diminishes with time. It’s a good idea to check planted fields, once it is possible to walk in them, to see if stand thinning is occurring.
Recent intense rainfall events (technically referred to as ‘toad stranglers’ or ‘goose drownders’) have left its mark on the 2002 corn and soybean planting season in Indiana. Of the very few farmers that have been able to plant corn in between the rainy spells, some are now wondering what to expect from corn fields that are under water or simply saturated.
Corn, like most crops, requires high levels of soil oxygen to successfully germinate. Flooded or ponded soils, or soils that are simply saturated, contain very little available soil oxygen. Germination won’t occur until soils dry out sufficiently. Soil oxygen is also essential for the metabolic processes of a developing seedling, including the active absorption and transport of nutrients from the soil. Without oxygen, the plant cannot perform critical life sustaining functions; e.g. nutrient and water uptake is impaired, root growth is inhibited, etc.
Anyway you look at it, flooded or saturated soils are not conducive to good germination or early seedling growth of corn. How long can corn withstand the oxygen-depleting effects of saturated soils?
Prior to leaf stage V6 (six-leaf stage as measured by visible leaf collars), corn can survive only two to four days of flooded conditions. If temperatures are warm during flooding (greater than 77°F) such young plants may not survive 24 hours. Cooler temperatures prolong survival. Compounding the outright effects of depleted soil oxygen reserves is the risk of soil-borne diseases on seeds or seedlings that are already stressed.
Plants younger than V6 are susceptible to damage for two reasons. First of all, the growing point in such young corn is at or below the soil surface and therefore is also subject to the stress of oxygen-depleted conditions.
Secondly, plants younger than V6 are in the process of trying to successfully establish a vigorous root system. Stunting or death of roots by oxygen-depletion can be a major stress for a plant that is not yet fully established.
Obviously, only time will tell whether a corn field that has been under water or saturated for long periods of time will require replanting. As you walk or wade through your fields and dig plants or seed, look for the obvious discoloration of the seeds or seedlings that indicates disease or death of the plant tissue.
Other flooding/ponding on-line references:
Hail and Flooding Damage in Corn (Univ. of Illinois, 1999) <http://spectre.ag.uiuc.edu/cespubs/pest/articles/199913h.html>
Effects of Flooding and Ponding on Corn (AGF-118-95)(Ohio State Univ.)
Genetic Help on the Way for Flood-Prone Corn (USDA-ARS, 1999) <http://www.ars.usda.gov/is/pr/1999/990426.htm>
Corn survival in wet conditions (Iowa State Univ., 1999) <http://www.ent.iastate.edu/ipm/icm/1999/5-24-1999/wetcorn.html>
Predicting Early Season N Loss (Purdue Univ., 1998) <http://www.kingcorn.org/news/articles.98/smb9802.html>
Among the many questions raised by Indiana & Ohio corn growers as the rain-delayed planting season continues is whether delayed planting should influence their seeding rate decisions for corn. As might be expected, several factors need to be considered.
First of all, what defines ‘optimum’ final population for corn in our two states? For most of our production areas, the answer is a range of final stands from 28-32,000 plants per acre (Nafziger, 1994; Paszkiewicz & Butzen, 2001). Some exceptions exist for that rule of thumb. Marginally yielding soils (consistently less than about 120 bu/ac) probably respond best to final populations nearer to 24,000 plants per acre, while exceptionally high yielding environments (greater than 180 bu/ac) probably respond better at final stands approaching 34-36,000 plants per acre (Paszkiewicz and Butzen, 2001).
So, the first step for Indiana & Ohio corn growers when considering late planting consequences for seeding rates is to determine whether they are normally seeding at rates that will achieve the optimum final stands for the productivity level of each field in their operation. Typically, seeding rates are calculated based on an assumed 90 percent success of germination, emergence, and seedling survival. For example, to achieve a targeted final stand of 30,000 plants per acre at harvest, one would seed at a rate equal to about 33,300 seeds per acre (30,000 divided by 0.90).
If you are already following these seeding rate guidelines, then delayed planting should not alter those seeding rates because the range of optimum final plant populations is similar for early and late planted corn. Table 1 illustrates the similarity of yield responses to population for corn planted at varying planting dates in research conducted by the Univ. of Illinois. Regardless of planting date, optimum grain yield occurs for most situations within a similar range of final populations.
Caveats: Choose What Fits Your Situation.
That said, it is important to recognize that no two farming situations are the same. Caveats and exceptions abound and should be considered when making a decision about seeding rates for late plantings.
Scenario #1: Soil temperatures for corn planted in late May or early June will be quite warm relative to that of usual late April or early May plantings. Couple that with the likely ample availability of soil moisture and the odds are that germination and emergence success will be greater than normal. Consequently, you may elect to reduce your seeding rate accordingly. Instead of planting 33,300 seeds to achieve 30,000 plants (90% success rate), you may elect to plant only 30,600 seeds per acre (98% success rate).
Scenario #2: If you eventually switch from your normal hybrid maturity to a much earlier maturity hybrid, you may actually want to increase your seeding rates by several thousand. Hybrid maturities (see Nielsen’s article on hybrid maturities in the May 10 Pest&Crop) of 100-day CRM or less often respond better to higher final stands than later maturity hybrids. Instead of aiming for final stands from 28-30,000 plants per acre, these very short season hybrids may respond better to final stands of 34-36,000 plants per acre (Paszkiewicz and Butzen, 2001). Consult your seed company sales representative for specific hybrid planting rate information.
Scenario #3: Later planted corn will be taller than early planted corn because its stalk elongation phase occurs during a time period that is relatively warmer (later in the season) than when early planted corn goes through the same phase. Not only will the plants themselves be taller, but ear placement will also be higher (same stalk node, but higher off the ground due to stalk elongation).
Consequently, a hybrid that is on the tall side to begin with will be even taller and its ears placed higher when planted unusually late. Such a combination of a tall hybrid and delayed planting will result in an increased risk of stalk lodging this fall if strong windstorms occur before harvest (anyone remember last October?).
One strategy to minimize this risk is to seed such a hybrid at rates closer to the low end of the optimum range in order to minimize the plant-to-plant competition that can cause etiolation (elongation under shade conditions) and thinner diameter stalks. Another strategy is to simply switch to a physically shorter hybrid.
Scenario #4: Later planting of corn, in and of itself, does not increase the risk of stalk rot development later in the season. However, taller, high-eared, late-planted corn will be more susceptible to the stalk lodging consequences of stalk rot IF stalk rot develops.
One of the primary factors that contributes to stalk rot development is severe stress (heat, dry soils, disease, hail, insects, cloudy weather, soil compaction) occurring early in the grain filling period that severely limits photosynthesis. The timing of that stress relative to grain filling is the critical determinant to whether stalk rots develop in corn of any planting date (anyone remember two years ago?). Planting strategies to minimize this risk would be similar to those of Scenario #3 above, as well as to avoid wet fieldwork (compaction) yet this spring.
Scenario #5: There will undoubtedly be a few fields tilled and planted on the wet side once field conditions get even close to being suitable for field work over the next few weeks. One consequence of doing so is a cloddy seedbed that does NOT promote good seed-to-soil contact for rapid and uniform germination.
IF the weather should suddenly switch from frequent rains to total dryness after such fields were worked and planted, germination would be extremely variable, if not disappointing (anyone remember 1991?). Along with the cloddy seedbed preparation, tilling and planting wet fields creates various forms of soil compaction (see T. Vyn’s article in the May 10 Pest&Crop) that are not conducive for successful root development.
IF you are forced into this wet fieldwork scenario, you may want to increase your seeding rate beyond what you normally use, in anticipation of unsuccessful stand establishment. Similarly, IF you decide to forgo some tillage in fields where seedbed conditions are marginal (characterized by a cloddy surface, ruts, uneven residue distribution) and plant no-till, you may want to increase seeding rates to compensate for the higher probability of greater seedling mortality.
Nafziger, E.D. 1994. Corn planting date and plant population. J. Prod. Ag. 7:59-62.
Paszkiewicz, Steve and Steve Butzen. 2001. Corn Hybrid Response to Plant Population [Online]. Crop Insights, Vol. 11, No. 6. Pioneer Hi-Bred Int’l Inc., Johnston, IA. Available at <http://www.pioneer.com/agronomy/corn/population_response.htm> (Verified 5/9/02).
Don’t forget, this and other timely information about corn can be viewed at the Chat ‘n Chew Café on the World Wide Web at <http://www.kingcorn.org/cafe>. For other information about corn, take a look at the Corn Growers’ Guidebook on the World Wide Web at <http://www.kingcorn.org>.
In previous articles in the Pest&Crop, I made the assertion that there is even more reason to plant no-till the longer that planting is delayed by wet weather. That recommendation is consistent for both corn and soybeans, and for rotation or continuous cropping situations, as long as suitable equipment is used and management (including pests) are near optimum. Farmers are (understandably) reluctant to change their time-honored tillage practices in the face of adverse weather, but are more likely to change when there are sound reasons for doing so. What follows is our attempt to explain some of the basis for our recommendation.
Evidence from Indiana:
Although there have been specific tillage trials conducted with multiple planting dates in other states, the local evidence supporting the recommendation for no-till in delayed planting situations is based on long-term experience. The best circumstantial evidence is our 27-year history of yield responses of corn and soybean to chisel plowing versus no-till planting on poorly drained, silty clay loam soils at the Agronomy Research Center (West Lafayette, IN) (see Tables 1 and 2). This particular study has received careful management throughout that whole period.
The planting date each year was consistently the first available opportunity - based on soil moisture in the seedbed zone - to do satisfactory secondary tillage on plowed plots after the calendar date of April 20 for corn, and after May 1 for soybeans. The planting dates that we achieved represent the practical range of what area farmers experienced in that 27-year period on similar tile-drained soils. The interpretation of the data might also be aided if the reader is aware that 5 year average yields of both corn and soybeans have remained fairly constant with time (i.e., no general increase in that 27 year period). Rotation corn averaged 176 bushels and rotation soybeans averaged 51 bushels per acre from 1975 to 2001.
It is not fair to compare yield data in either Table 1 or 2 among planting dates because corn hybrids changed 9 times, soybean varieties changes 13 times, and because we don’t have either multiple planting dates within a year or an equivalent number of years represented within each 10-day interval. However, the results can be used appropriately to compare relative crop responses to tillage system or rotation within the planting period.
With corn following soybeans or corn, it is quite clear that no-till is more likely to result in similar yields as after chisel plowing when corn is planted in late May versus late April (Table 1). Based on these results, no farmer can afford to do tillage for corn if yield responses are less than 4 bushels per acre. Furthermore, additional planting delays and cloddy seedbeds with tillage involve even more risk of yield loss.
For soybeans following corn, or for soybeans after soybeans, it is also quite clear that there is progressively more yield advantage with the no-till system as planting date is delayed (Table 2). In fact, soybean yields with no-till have averaged higher than those with conventional tillage with planting dates after May 20. So even if farmers decide to shift acreage into soybean from corn and, consequently, plant soybeans after soybeans, both income and time would be lost by doing unnecessary tillage.
Additional Suggestions for Moist Soil Situations:
No-till becomes a more and more expedient and practical system with progressively later planting of either corn or soybeans. Long-term success with no-till, fall strip-till and other high residue systems for corn will, or course, require careful attention to drainage, fertility and pest management. But even in this difficult spring, farmers might benefit from no-till or stale seedbed planting systems. In fact, planting delays makes conservation tillage more imperative.
1. Soybean Yield Loss in 2002.
Those who can least “afford” to plant soybean after soybean are those on sloping soils with low organic matter levels. Future crop yield potential is sacrificed when soil is lost.
Most farmers have their tractors attached to the corn planter, soybean drill and/or hay mower-conditioner waiting for a break in the wet weather to get to the important farming tasks at hand. With the persistent wet weather and the increasing reality that delayed corn/soybean planting and forage harvest is reducing potential income, now is the time to lessen the effect of the “too much to do with too little time” collision by evaluating your labor and/or equipment needs.
The reduced income concern for forage crops is not primarily related to yield, but is related to loss of quality as the crop matures. As forages mature they increase in cell wall content (fiber) and, thus, are less digestible as compared to being harvested in a less mature stage of growth. Forages will also decline in crude protein content as they mature. As an example, alfalfa harvested at very early flower may have a value of over $100 per ton, but will quickly devalue to less than $80 per ton if harvested at mid-flower.
Part of the answer to reducing potential income lost is enlisting the help of capable people. Are there retired farmers or individuals that work the traditional 40 hours-per-week job, but willing to work more, within your community that could be enlisted to get through the time crunch? With capable help it should be feasible to get more tasks accomplished during a day and be dollars ahead than “going it alone.”
Individuals that custom-harvest forages will struggle more than usual this year in getting the first hay crop packaged with high quality in timely fashion. Individuals that do not have a contract with a custom operator may want to seek other means of being “closer to the front of the line” in getting hay harvested so it has better quality than straw. Is there idle forage harvest equipment at a farm or at an equipment dealer’s lot that could be leased and operated by you or another person that has experience with safe use of the equipment?
Planning is an important part of any effective business. Some quick planning now regarding labor and equipment could help get more farm-related tasks accomplished when sunny weather occurs again.
Indiana hay production can be very challenging due to the high humidity environment and unexpected rainfall. High quality hay is an important commodity in Indiana due to the demand brought on by the ruminant livestock and horse industry. Research (C.A. Rotz et al. 1987. Transactions ASAE 30(3):630-635) has shown that a properly set mower-conditioner can reduce the drying rate of first cutting alfalfa by 80% as compared to using a sickle bar mower. This research also indicates that a mower-conditioner is the best investment for reducing hay-drying time. Consider the following points for proper mower-conditioner setup and adjustment.
The first item to look at on a mower-conditioner is the cutting mechanism. There are two types offered by equipment manufacturers. The first type of cutting system is a sickle bar mower-conditioner and the second type is a disc mower-conditioner. Either type of cutting system is very effective when it is properly maintained. On sickle bar mower-conditioners it is important that the sickle knives are sharp and properly held down to the guards with the hold-down clips. It is also important to make sure the points of the guards are not bent and that the feather sheet, the place where the guards bolt on, is straight across the entire width of the machine. Refer to the owner’s manual on how to straighten or replace the guards. On disc mower-conditioners, it is important to make sure the knives are sharp. If they are dull, chipped, or worn, they need to be replaced. A properly maintained cutting system will enable the entire crop to harvested at the correct height and then allow it to flow smoothly through the mower-conditioner.
The reel found on sickle bar mower-conditioners is the next item to adjust. The reel effects how the crop material is fed through the machine. If it is not set at the correct position and speed, you could experience bunching and wadding in front of the conditioning rolls or the forage wrapping around the reel. For down and tangled crops, such as a late-harvest first cutting of alfalfa, the reel speed needs to be set up to 25% faster than the ground operating speed. However, if the crop is short and light, then the reel should be set to match the ground speed. If the reel is wrapping forage around itself or throwing forage out in front of the mower-conditioner, then the reel is set too fast. If the reel is set too slow, the conditioning rolls will not feed smoothly and evenly. If the rolls result in clumps or slugs, then there is the potential for the hay to have moldy spots because the clumps or slugs will dry slower than rest of the windrow.
The final and most important item to examine is the conditioning rolls. The function of the conditioning rolls is to crimp or crack the stems of grasses and legumes (Figure 1).
The following is a list to follow when setting up the conditioning rolls on your mower-conditioner.