Field Crop News
Website Address: http://fcn.agronomy.psu.edu/
September 16, 2005 Vol. 05:12
IN THIS ISSUE:
Mark Your Calendar
- No-Till Field, October, 11, 2005, 10:00 a.m. - 2:30 p.m., Future View Farm, Willow Street, PA. To register contact the Lancaster County Extension Office at 717-394-6851 - details follow.
- Certified Crop Advisor Workshop Planned for November 2, 2005 - details follow.
Weather Outlook
Production
Pest Management
Agents Corner
MARK YOUR CALENDAR
No-Till Field Day
Oct. 11th, 10:00 a.m. - 2:30 p.m., Future View Farm, Jeff Frey Family, Willow Street, PA. Hosted by: Lancaster County Extension, Lancaster County Conservation District, NRCS and Local Equipment Dealers.
Call the extension office to register. Free lunch for those who register: 717-394-6851
Topics will include
- Transition from Tillage to No-till
- Crop Residue Management
- Establishing Cover Crops and Selecting the Appropriate Species
- Making No-till work for you
- Manure Management in No-till
Jeffrey S. Graybill, CCA, jsg18@psu.edu
Lancaster County
CERTIFIED CROP ADVISOR WORKSHOP PLANNED FOR NOVEMBER 2, 2005
The Certified Crop Advisor (CCA) program certifies crop advisors who demonstrate crop management experience and pass comprehensive state and national exams covering nutrient management, soil and water management, integrated pest management and crop management. On November 2, Penn State faculty and staff from the departments of Crop & Soil Sciences, Entomology, and Plant Pathology will hold a one-day workshop at University Park to prepare individuals planning to take the CCA exams in Harrisburg on February 3. The workshop will be held in Room 504 Agricultural Sciences and Industries Building. It will start at 8:30 a.m. and end at 5 p.m. There is no charge for attending the workshop. To register, call or e-mail Lisa Crytser (814-865-2543, lac8@psu.edu. Everyone serving or planning to serve the crop production industry should take this opportunity to become certified.
The registration period for the February 3 exams is October 3 to December 16. Registrations received after December 16, 2005 will not be processed. The fees to take the state and national exams are $100 and $125, respectively. For more information about the CCA program visit the ASA website www.agronomy.org or contact Amy Bradford abradford@pennag.com. Because the average passing percentage over all testing opportunities is only 60%, the one-day workshop may provide the advantage you need for certification success.
Jan Pruss, jap5@psu.edu
Crop Management, Crop and Soil Sciences
WEATHER OUTLOOK
"Elijah had a frame like all of us and he prayed fervently and it did not rain on the earth for 3 and a half years" (James 5:17) Well, these are becoming like the days of Elijah, but thankfully, it's been only about two-three weeks since most of the state has had much rain. The first half of September is at record pace for dryness, but that should have changed some by the time you read this. The latest hurricane (Ophelia) will be passing close to New England as the weekend begins and a trailing disturbance will cause showers in parts of the state on Saturday as noticeably cooler air arrives. In fact, a couple of chilly mornings (daybreak temperatures in the 40's and 50's) are likely on Sunday and Monday. Warmth will return by mid-week (Sept 21), preceded by a smattering of showers in the northern tier. A see-saw weather pattern marked by alternating shots of cool air punctuated by early autumn warmth will be the rule for the period Sept 21-Oct 14. While showers will become more regular, precipitation is expected to be below average. The Tropics will remain quite active into mid-October and it is possible that one storm will effect much of the Atlantic Seaboard, however the real concern is that another potent storm will strike the Gulf Coast.
Paul Knight, pgk2@psu.edu
Pennsylvania State Climatologist
PRODUCTION
KEEP THAT ALFALFA STAND?
As winter weather approaches producers question if their alfalfa stands are worth keeping another year or should they be rotated to corn nest spring. Unfortunately this is not always a yes or no decision. However, recent research can help in assessing the productivity and profitability of a questionable alfalfa stand.
The magic number of plants, that traditionally indicated when it was time to rotate out of alfalfa, has been 4 - 5 plants per square foot. However, depending on fertility and weed invasion, alfalfa stands with 5 plants per square foot can yield as much as a stand with 10 or 15 plants per square foot. The correlation between plants per square foot and yield is very low since individual alfalfa plants respond to decreasing stand density by producing more stems. Increased stems per plant compensates for fewer plants and maintains the yield.
A better indicator than the number of plants of the productivity of an alfalfa stand is the number of stems per square foot. Fields with 55 or more stem per square foot produce maximum yields. As the stem number declines below 55 per square foot yields begin to decline. Once stem numbers falls below 40 per square foot alfalfa fields begin to loose profitability and should be rotated out of alfalfa.
Marvin Hall, mhh2@psu.edu
Forage Management, Crop and Soil Sciences
CONSIDERATIONS FOR SUCCESSFUL WHEAT STANDS
Paying attention to the details of winter wheat planting guidelines is a key factor in maximizing the yield potential of this crop. Much of the yield potential of wheat is based on decisions made at planting.
For optimum yields, seed winter wheat between September 20 and October 3 in short season areas of the state, between September 25 and October 8 in medium season areas, and between October 1 and October 15 in longer season areas of the state in southeast and southcentral counties. The desired plant population for winter wheat is 1.2 to 1.5 million per acre (28 to 34 plants/sq ft). This requires a seeding rate between 90 and 150 pounds per acre, depending on seed size. Consider the lower rates in longer season areas and the higher rates in other parts of the state. The seeding rate should be based on the number of seeds per acre rather than pounds per acre and should account for the germination of the seed. Some seedlots are slightly larger this year and this could reduce the plants per acre if seeded on a bushel or pound per acre basis. Strive to plant the seed 1-1.5 inches deep. Adjust the drill to maximize seed depth uniformity: make sure the tongue is level, the down pressure is appropriate for the seedbed and the disk openers are in good condition. Use the charts below to estimate seeds/ft of row and pounds of seed per acre during the calibration process.
| plants | plants | 6 in. | 7 in. | 7.5 in. | 8 in. | 10 in. |
|---|---|---|---|---|---|---|
| 24 | 1.05 | 12 | 14 | 15 | 16 | 20 |
| 26 | 1.13 | 13 | 15 | 16 | 17 | 22 |
| 28 | 1.22 | 14 | 16 | 18 | 19 | 23 |
| 30 | 1.31 | 15 | 18 | 19 | 20 | 25 |
| 32 | 1.39 | 16 | 19 | 20 | 21 | 27 |
| 34 | 1.48 | 17 | 20 | 21 | 23 | 28 |
| 36 | 1.57 | 18 | 21 | 23 | 24 | 30 |
| 38 | 1.66 | 19 | 22 | 24 | 25 | 32 |
| 40 | 1.74 | 20 | 23 | 25 | 27 | 33 |
| Seeds per sq. ft | Seeds millions/acre | Seed size (seeds/lb.) | |||
|---|---|---|---|---|---|
| 11,000 | 13,000 | 15,000 | 17,000 | ||
| lbs/acre | |||||
| 24 | 1.05 | 95 | 80 | 70 | 61 |
| 26 | 1.13 | 103 | 87 | 76 | 67 |
| 28 | 1.22 | 111 | 94 | 81 | 72 |
| 30 | 1.31 | 119 | 101 | 87 | 77 |
| 32 | 1.39 | 127 | 107 | 93 | 82 |
| 34 | 1.48 | 135 | 114 | 99 | 87 |
| 36 | 1.57 | 143 | 121 | 105 | 92 |
| 38 | 1.66 | 150 | 127 | 110 | 97 |
| 40 | 1.74 | 158 | 134 | 116 | 102 |
Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences
Pest Management
FALL HERBICIDE TREATMENTS - HOW THEY FIT INTO OVERALL WEED MANAGEMENT PLANS:
by Mark Loux, Jeff Stachler, and Anthony Dobbels - Ohio State University
The following article was written by our colleagues at Ohio State University. They have had a great deal of experience with fall applications and control of winter annual weeds and certain perennials. We certainly appreciate their research and can learn from their experience.
Bill Curran, wcurran@psu.edu
Weed Management, Crop and Soil Sciences
Part I. Fall herbicide treatments have become a fairly common practice for some no-till producers, who recognize their value for managing certain tough winter weeds and providing a weedfree seedbed in the spring. In previous falls' C.O.R.N. articles on this subject, we have listed what we feel to be the most effective treatments based on our research.
This list remains essentially unchanged between last fall and this fall, and it includes:
Any crop next spring-
Glyphosate + 2,4-D
Soybeans next spring-
Glyphosate + 2,4-D
CanopyEX + 2,4-D
Sencor + 2,4-D (excluding dandelions)
Corn next spring-
Glyphosate + 2,4-D
Simazine + 2,4-D
Basis + 2,4-D
Other herbicides (Valor, Scepter, Python, Aim, etc) can be applied in the fall, but most of these will not effectively control winter weeds unless they are combined with one of the herbicide treatments listed above. Effective control in the fall can be obtained with treatments costing $5 to $10 (excluding application cost), and we question the value of treatments that cost more than $10. For control of winter annual weeds, apply herbicide anytime after early October. For the most effective dandelion control, delay application until after a frost. We have applied as late as early December for control of winter annual weeds, but we generally recommend application when dandelions are still mostly green, or by mid-November if possible. Apply glyphosate-containing treatments with ammonium sulfate, and additional nonionic surfactant if specified by the product label. Treatments that do not contain glyphosate should generally be applied with crop oil concentrate for best results.
What we have not addressed in previous articles is where fall treatments fit in the overall weed management plan, and at what point in the crop cycle residual herbicides are best applied. Some reminders on what we are trying to achieve in no-till crops with weed management programs. First, the program has to control winter annual, biennial, and perennial weeds that emerge the previous fall or are already present at the end of the previous crop's harvest. Weeds in this category include chickweed, purple deadnettle, marestail, wild carrot, and dandelion, among others. These weeds overwinter and regrow in the spring, interfering with crop establishment and early-season growth, and they need to be controlled by a fall or early-spring herbicide application. A secondary goal is to prevent seed production by these weeds, which prevents increased problems in the future. The other group of weeds for which control is essential includes summer annuals, such as ragweeds, foxtails, lambsquarters and black nightshade, and warm-season perennials, such as johnsongrass, milkweeds, and perennial vines. The early-emergers of these weeds can interfere with crop establishment, but the weeds in this group mostly compete directly with the crop during the growing season.
Current weed problems in soybean production lead us to believe that producers take advantage of the full benefits of residual herbicides (Canopy, Sencor, Valor, Scepter, etc) by applying them in the spring, rather than in the fall. Use of residual herbicides in the spring accomplishes the following in soybeans (both Roundup Ready and conventional): controls or helps control weeds that are problematic for glyphosate and other postemergence herbicides - marestail, giant ragweed, lambsquarters; reduces early-season weed competition so that soybean yield is not reduced if postemergence herbicide application is delayed; creates a wider window for postemergence herbicide application; and allows slightly later postemergence application to control later-emerging summer annual and warm-season perennial weeds. Residual herbicides are especially helpful in situations where the soybean canopy is slow to develop, because this tends to allow late emergence of weeds that are not suppressed by the crop.
Marestail, lambsquarters, and giant ragweed have been especially problematic in Roundup Ready soybeans in recent years. Our primary recommendation with regard to management of these weeds is the use of a combination of preplant (residual) and postemergence herbicides, and the residual herbicides will generally be most effective when applied in the spring. Many preemergence soybean herbicides can provide season-long lambsquarters control when applied in the spring. Marestail control may be more variable than lambsquarters with residual herbicides, but our research shows that spring applications are much more effective than fall applications for control of marestail that emerge into June. With regard to giant ragweed, which emerges well into June, one hopes that residual herbicides control at least some of the early emergers and slow down its growth rate, so that the postemergence herbicides are applied to relatively small plants. The most effective residual herbicides on giant ragweed are CanopyEX. SynchronyXP, Scepter, FirstRate/Amplify, and Gangster, although the effectiveness of all of these can be limited in ALS-resistant ragweed populations.
Part II. There appear to be two basic approaches that producers take with regard to fall and in-crop applications, and the choice of approach and the nature of the weed population dictates somewhat when residual herbicides can be used.
Approach 1. This approach should be used only in Roundup Ready soybeans. The herbicide program consists of a fall treatment, followed by a postemergence glyphosate application in the Roundup Ready soybeans. This approach will be most effective when the soybeans are planted in a timely manner, followed by average or above-average rate of growth and development. Key points on this approach:
- there is no spring preplant burndown treatment, so the use of a residual herbicide in the fall is recommended, to control weeds as long as possible into the spring and build the appropriate application window for the postemergence application.
- In OSU research with fall applications, chlorimuron-containing herbicides (CanopyXL, EX) have typically provided the longest period of residual activity into next year's soybeans. A rough ranking of fall-applied herbicides for the length of residual control: CanopyEX > Gangster > Scepter > Valor = Sencor = Python. Higher rates of these herbicides usually improves the length of residual control into next growing season, however, the slight increase in residual control for some of these herbicides will not be offset by the increase in cost. A minimum of 1.1 oz/A of Canopy EX or 2.5 oz/A of Canopy XL is necessary for optimizing dandelion control and providing some level of residual control into the following spring. Higher rates certainly provide longer residual activity into next growing season, but will not improve control of ALS resistant species nor guarantee a reduction in the number of applications next year.
- Essential to the success of this approach is that the first postemergence glyphosate application be made when the majority of the weeds are 4 to 8 inches tall (giant ragweed can be slightly larger). This may occur earlier in the season with this approach compared to when residual herbicides are used in the spring, resulting in the risk of late-emerging weeds that escape treatment. A second postemergence glyphosate application several weeks after the first can therefore often be the key to getting "season-long" control with this approach.
- Because residual herbicides do not last as long into the growing crop when applied in the fall, this approach may not be the most effective for the following types of weeds: those capable of germinating well into the growing season (giant ragweed, marestail, eastern black nightshade, pokeweed, burcucumber); and those that are especially problematic in Roundup Ready soybeans because they demonstrate occasional tolerance to glyphosate or have a history of developing glyphosate resistance (giant ragweed, velvetleaf, lambsquarters, waterhemp, marestail). It is our opinion that this approach also results in more selection pressure for herbicide resistant weeds compared to the following one, since two postemergence glyphosate applications may frequently be required to make this approach work.
- Producers often go with this approach with the hope that it is a two-application program (fall plus postemergence). In fact, many find that this becomes a three-application program (fall plus two postemergence) more often than they would like due to the diversity of weed species that we have in many Ohio soybean fields. Should you find yourself making three applications more often than not, than the next approach may have a better fit.
Approach 2. This approach is effective in Roundup Ready soybeans, and it is the most effective weed management program in fields that will be treated with herbicides this fall and planted to conventional (non-Roundup Ready) soybeans next spring. This is a three-application system consisting of a fall, spring preplant, and postemergence application. Some key points on this approach:
- The primary advantage of this approach compared to the first one is that residual herbicide(s) applied in the spring provide a longer period of weed control after soybean planting compared to fall applications. Because of this, there tends to be a greater number of herbicides from which to choose, since some of the herbicides that are not as long-lived as chlorimuron can still have a good fit in the spring.
- In OSU research, this is the most consistently effective approach to some of the weeds listed above, as well as ALS-resistant weed species. Several residual herbicides can provide season-long control of lambsquarters, velvetleaf, and eastern black nightshade when applied in the spring. There is no question that residual herbicides are most effective on marestail and giant ragweed when applied in the spring (assuming some rain occurs within a week or so of application).
- In our opinion, this approach helps reduce the selection for herbicide-resistant weeds, since it allows for the use of several different herbicide sites of action within the soybean crop.
- This approach tends to provide the most flexibility in the postemergence application timing, which can counteract other factors that wreak havoc with postemergence timing, such as bad weather, a heavy postemergence workload, and slow soybean canopy development.
- A possible disadvantage of this approach - it may be too wet to apply preplant residual herbicides in the spring, although if the field is dry enough to plant it should be dry enough to receive an herbicide application. Another disadvantage for spring applications may be a lack of sufficient rain for activity, which is more of a problem with late-spring applications.
- The preplant residual herbicide can be applied with a low rate of glyphosate or 2,4-D ester to control any small weeds that emerge in the early spring. This is most likely to occur where the fall application lacks residual activity (glyphosate + 2,4-D, for example). It is possible with this approach to apply residual herbicides in fall and spring, which may ultimately be the most effective herbicide program. However, use of residual herbicides is not essential in the fall with this approach. We have heard from a number of producers who have decided to apply glyphosate and 2,4-D in the fall, saving the residual for the spring. Where chlorimuron-based herbicides are used in fall and spring, be cautious about exceeding the maximum amount of chlorimuron for soils with pH of 6.8 or higher.
- a final note on this approach (a disclaimer really): due to variation in weed emergence patterns, soybean development, and the occurrence of herbicide resistance, etc, from year to year, there is no guarantee that a second postemergence application won’t be needed in this approach. However, the chances are much less than with the first approach, and this approach does a better job of managing postemergence workload and controlling the most problematic weeds.
Note on fall treatments and weed control in corn: The use of herbicides in the fall does not really influence the choice of herbicide program used in next year's corn crop. This is because: a) the fall-applied herbicides (glyphosate, simazine, or Basis) often lack significant residual in the spring on common broadleaf and grass weeds, and b) corn is more sensitive than soybeans to early-season weed competition, resulting in a need for preemergence herbicides to ensure effective corn stand establishment and early-season growth and development.
Agents Corner
Capital
As I write this September 9, soil conditions are dry. Dave Johnson, Director of The Southeast Agricultural Research and Extension Center at Landisville, reports less than two inches of rain since August 1. There is no rain in the forecast and daily high temperatures are forecast to be in the eighties. Late season drought conditions have accelerated corn dry down and silage producers are scrambling to harvest corn before moisture drops lower. High moisture shelled corn is being harvested. Yield reports range from average to slightly above average.
Full season beans in pods are medium size and still green. Leaves are dropping rapidly. Double season beans are another story. Pods and beans are small. Drought stress is showing up on shallow soils. This crop needs moisture now.
Summer seeded no-till alfalfa planted into small grain stubble is emerging unevenly. About 15% of plants are in the first true unifoliate stage. Another 10% is in the cotyledon stage. An inch of rainfall per week from now on would be a big help for these seedings.
There is still time left in most parts of the state to conduct the Late Season Corn Stalk Nitrate Test. Details of this excellent test can be found at this website: http://www.aasl.psu.edu/Corn_stalk_nitrate.html. The test works on any corn field and provides users with an end of season nitrogen management "report card," indicating Low, Optimum or High nitrogen availability during the growing season. The test is available from Penn State's Analytical Agricultural Laboratory Services and Agri Analysis in Leola. Pay particular attention to collecting, handling and shipping the sample to the lab.
Mark Goodson, mwg1@psu.edu
York County
NORTHWEST
The only good thing to come out of the Hurricane Katrina experience was badly needed rain for our area. Some parts of the region received up to 4 inches of rain from the storm. It was a really nice steady rain over several days, but with the conditions we had prior to that, it was a little too late to help many crops. The corn harvest was pretty much underway at that point in time anyways. It may help the soybeans to develop a little more. It greened up some of the hay fields and pastures short term, but very little effect long term.
Corn silage harvest got underway in the end of August for the region, somewhat earlier than expected, but moisture checks showed moisture levels in the low to mid 60's. The corn stalks are drying down fast though they still appear green. There have been some incidents of Northern Corn Leaf Blight in fields in the region. It may be wise for producers to look for some resistant hybrids as they make their seed corn purchases this fall and winter. With the dry weather it shouldn’t take long to finish up the silage chopping. No rain delays or weather to hold up the chopping process. The farther north and west in the region the better the crop conditions and much higher the yields seem to be. Joel Hunter's corn silage plots are averaging in the 20 ton or higher ranges on many varieties. It will be interesting to see how the different counties in the region compare.
It appears that some producers are going to utilize the Late Season Corn Nitrate Test available from Penn State to see how their nitrogen programs are working. As they look for ways to reduce costs, this could be a relatively cheap way to do some assessments.
This should be a very good fall for producers to seed cover crops as the corn silage comes off early. They should be able to go in and seed cover crops as soil conditions are good at this time. Make sure producers do some checking around on prices as Sjoerd has found a wide range in prices from different suppliers. He suggests making some phone calls to save some money on cover crop seed. Let’s hope it rains enough to get the cover crops started then.
Nelson Smith, nes2@psu.edu
Clarion County
Southeast
The southeast is extremely dry. A half inch to an inch of rain has fallen in the past month and none in the past few weeks. Silage harvest is nearly complete except for some late planted corn. Third and fourth cutting alfalfa is done with yields being short. Grass and alfalfa seeding if they were planted are not doing much, just waiting for moisture. Some short season corn has been combined, yields are variable, but moistures are between 18-24%, most are waiting for mother nature to dry it down more before they get too carried away with combining. Soybeans are yellowing and dropping leaves, some early beans are not too far away from harvest. Second and third cutting grass hay is more weeds than hay. Forecast is for a half to three quarters of an inch of rain Thursday and Friday, we sure need something to settle the dust. We are 300-400 GDD's ahead of normal which has sped up the maturity of all crops.
Sept 8th we had Fall Equipment Tune-up Clinic in Hamburg, Berks County which focused on mowing, tetting and raking which over 100 area farmers attended. They had the opportunity to compare a disc mower with rubber rolls to a haybine with rubber rolls and a discbine with impellers. Also tetters and rollabar rakes to rotary rakes. Two area equipment dealers were on hand to talk about set up and maintenance. Following the field demonstrations Marvin Hall discussed how hay dries and what can be done to shorten that time.
Andrew Frankenfield, adf13@psu.edu
Montgomery County
SOUTHWEST
Crop conditions in the southwest are variable. With the rainfall attributed to Katrina, areas southwest and west of Westmoreland County, received upwards of two inches of rain. Most areas including Westmoreland, Fayette counties and east got less than a inch of rain. Couple that with the extremely variable moisture amounts in July and August, things are and have been quite dry over much of the southwest since early July.
Corn silage harvest is mostly completed, the soybean crop is shutting down, hay has stopped growing as have lawns, gardens, etc. Corn silage harvest is ranging from 8 tons per acre to 20 tons per acre, with most at less than 15 tons. Farmers are also reporting hay crop losses of 2 or more tons (HE) per acre. Pastures are non productive and livestock farmers have been feeding hay and some have chopped corn silage as an alternative feed source for the winter months.
On a brighter note, the fair weather has allowed fall seeded small grains to get planted in a timely manner. The bottom line is 2005 was pretty much a complete reversal to 2003 and 2004.
Don Fretts, dcf3@psu.edu
Montgomery County