March 29, 2002
|
Tillage Soil fertilityWeather/climate
Weed Control Alfalfa and Hay Management Resources CropWatch AgNews
|
Tillage destroys residue, exposing the soil to the forces of erosion. The same raindrop impact that causes erosion can cause soil crusting when residue is not there to absorb the energy of the falling drop. This crust reduces infiltration and increases runoff, making the rainfall or irrigation less effective. The same residue acts as a mulch to reduce evaporation from the soil surface, further conserving soil moisture. Producers should adjust and operate machinery to keep as much residue on the soil surface as possible.
Tillage drys the soil, often to the depth of tillage. An average silt loam soil can hold about 2 inches of available soil moisture per foot of soil. Tilling 6 inches deep and allowing the soil to dry to the depth of tillage could result in a soil moisture loss of up to 1 inch of water. Shallower tillage, even row crop cultivation, can still result in moisture losses of about 1/2 inch. By not tilling or cultivating, these moisture losses can be minimized and the residue can be retained. A moist soil with residue cover doesn’t get as hot as a bare soil, allowing better root development during dry conditions.
Tillage destroys soil structure by breaking up the existing structure and pulverizing the soil surface, making the soil prone to crusting. This loosened soil is easily packed down on the next pass through the field, often packing the soil tighter than it was before the initial tillage. Tillage pans are formed below the tillage depth where the weight of the implement is being carried. Care must be taken especially on wet soils as these are the ones most easily compacted. Tillage to “dry out” soil actually makes wet spots in fields wetter because water cannot drain away naturally when the tillage pan forms. When it does turn dry, this compaction restricts root growth and the crop roots cannot reach moisture stored in the soil below that compacted layer.
Tillage mixes air into the soil profile, oxidizing crop residues and organic matter. This adds to CO2 in the atmosphere and reduces the amount of carbon stored in the soil. With less organic matter, water and nutrient storage is much less. Also, organic matter acts like the “glue” that holds soil particles together and builds soil structure.
By parking the tillage tools, continuous no-till allows mother nature to build soil and soil structure. After about 15 to 20 freeze-thaw cycles and/or wetting-drying cycles, vertical soil structure builds up enough to heal the soil from tillage. At the tillage depth, there are only about three to five cycles per year. This is why many no-tillers talk about something happening to the soil after about five years of no-till. They finally accumulated the 15 to 20 cycles needed to build soil structure, improving root and water penetration into the soil.
Tilling every other year, or even once in a while, erases those cycles and soil structure cannot build. To get the full benefits of no-till, every crop in the rotation needs to be no-tilled. With Nebraska’s soils, long-term no-till, properly managed, will improve the soil and provide great returns.
Paul Jasa
Extension Engineer
The first system impacted the northern half of the Panhandle and western portions of the Sandhill region March 15-17. Snowfall totals averaged close to 12 inches across this region, with up to 22 inches reported in the northwestern corner of the Panhandle. The second system moved across southwestern, south central, and southeastern Nebraska March 23-25. Moderate snow was reported throughout this region, with the heaviest totals reported across southeastern Nebraska.
|
It appears that a vast area encompassing the southern half of the Panhandle, the southern half of the Sandhills, southwestern, central, and south central areas of the state continue to deteriorate from the lack of above normal precipitation. Much of the surplus precipitation that fell from the end of the 2001 growing season through the end of November has been eliminated. Attention is now focused on whether precipitation deficits will continue as we enter the critical spring recharge period.
Long lead outlooks don’t offer much promise. They indicate that during April all of Nebraska should experience drier than normal conditions, with the eastern two-thirds of the state having the greatest likelihood of receiving below normal moisture. If this forecast proves true, I expect that much of the state will be classified as experiencing moderate to severe drought conditions.
Snow pack data that was released at drought meetings in Colorado and Wyoming in early March doesn’t offer much hope for inflow rates into the Platte River system. As of March 1, snow pack in the Platte River basins of northeast Colorado and southwest Wyoming were running at 56% of the historical average. The Natural Resource and Conservation Service indicated that it would take 276% of normal snowfall through the middle of April just to bring the snow pack back to historical norms.
Snowpack feeding the southern branch of the Platte River stood at less than 50% of historical average on March 1, while snowpacks were running between 50% and 70% of normal for basins feeding the north branch. In addition, the Republican river was running at less that 10% of historical flows from the Colorado border east to the Harlan County reservoir.
Colorado and Wyoming snowpacks typically reach their peak depth by April 15. With only a couple of weeks left, it is apparent that the snowmelt will be significantly below normal this spring. On March 1, flow rates on both branches of the Platte River entering Nebraska were projected to be less than 70% of the historical average this spring and summer. This forecast was based on the assumption that normal precipitation would fall through May 1.
Short-term forecasts give no indication that another major storm is on tap for the Central Plains during the next 10 days. In fact, only a couple of minor disturbances are projected to move across the region and they will contain limited moisture. Temperatures should begin to increase through next week as a rather strong ridge begins to build over the south central United States. Conditions should be very good for producers to begin field preparation activities.
Al Dutcher
State Climatologist
School of Natural Resources
Evaluate stands early this spring. Older, dryland fields need 40 new shoots per square foot coming from two or three plants for maximum yields. If fewer than 30 shoots are present, new fields may need to be planted. Very productive sites, such as irrigated and sub-irrigated fields, should have at least 55 shoots per square foot from four to six plants. Consider new plantings if these fields have fewer than 40 shoots. We tend to lose about one tenth of a ton in yield potential for every shoot below these numbers.
Check for these densities in several areas when shoots are 6 inches tall. Since some shoots begin growing later than others, stands with enough plants but slightly low shoot density may be all right, especially if shoot height and distribution is uniform.
Bruce AndersonCheck alfalfa condition early
Alfalfa usually comes through winter in pretty good condition; however, this year some fields went into winter in weakened shape because of the dry summer. In addition, this winter was so mild that plants may have bounced between winter dormancy and greening up all season.
Extension Forage Specialist
Controlling winter annuals in no-till corn
| ||
Why have these weeds become a problem and what do we do about them? First, we need to talk a little about biology. Since these weeds are annuals they have one year to germinate, grow vegetatively and set seed. Basically it is the annual's job to produce seed so that the species will continue the next year; everything else is secondary. The life cycle of these winter annual weeds differs from summer annuals like foxtail and velvet leaf which typically germinate and produce seed within the growing season. These winter annual weeds actually germinate in the fall and begin growing before winter. In spring. they usually bolt and produce seed before corn or beans are planted.
Why should you worry about controlling winter annuals? Many southeast Nebraska producers have found that no-till fields are excellent at conserving moisture in dry-land situations. Unfortunately winter annuals will use valuable moisture that could be available to the crop.
Many people wonder why have these winter annual weeds have become such a problem lately. One speculation is that winter annual weeds are popping up in no-till corn fields where the increased use of Roundup-Ready soybeans means there is little or no herbicide residual to control these weeds. When conventional soybean were the norm, traditional herbicides provided residual control to keep many of the winter annuals from germinating or growing in the fall.
What are the best herbicides for control of winter annuals. Well the biggest issue is timing. Most of the herbicides work best before the weeds have bolted. This typically requires monitoring fields early and spraying as soon as temperatures warm up enough for plant growth. Below are several products that will provide control of henbit and will provide similar or better control of horseweed (marestail), pennycress, and other winter annuals.
The fall treatments should provide good control but may not eliminate the need for a spring burndown.
Brady Kappler
Weed Science Educator
Beyond (BASF), which has the same active ingredient as Raptor, is now labeled in Clearfield (Imi) wheat.
Guardsman Max (BASF) is a relatively new pre-emergent herbicide for corn. It replaces Guardsman by using Outlook premixed with atrazine instead of Frontier. Plateau (BASF) now has a full label in rangeland and pasture.
Raptor (BASF) is now labeled for alfalfa and dry beans.
Valor (Valent) is a new preemergence and pre-plant burn-down compound from Valent for small-seeded broadleaf control in soybeans without significant rotational concerns.
Yukon (Monsanto) is a premix of 2/3 ounce of Permit and 4 ounces of Dicamba for use in corn.
Brady Kappler
Weed Science Educator
|
Two contrasting models of global climate change were used to study winter wheat responses. Both of these models indicate increased temperatures compared to current temperatures; the more optimistic model indicates less of a temperature increase than the pessimistic model. The optimistic model also indicates increased precipitation in southeast Nebraska compared to current precipitation. In the Panhandle both models project less precipitation in the coming years while the optimistic model projects less of a decrease.
A current state of the art wheat model was used to simulate wheat yields and grain protein content. Responses from two contrasting winter wheat cultivars were studied, one adapted to Nebraska conditions and one adapted for warmer conditions as found in Kansas. The choice of the latter cultivar was based on the premise that cultivars currently grown in warmer climates might be immediately adaptable to projected future conditions in Nebraska.
Two sowing dates were used in this study. One sowing date represented the current sowing date while the other sowing date represented the day when the average air temperature from the climate change models was the same as the current average sowing date temperatures.
Alliance results
For Alliance, yields from the first sowing date for both cultivars using the pessimistic climate change model projections were less than the simulated yields using the current weather data. For the second sowing date using the pessimistic climate change model projections, yields were almost equal to yields simulated with current weather data. Using the optimistic projections, on the first sowing date for both cultivars, simulated yields almost equaled simulated yields using the current weather data. On the second sowing date, simulated yields using these optimistic projections exceeded the yields using the current weather data. However, the variability associated with all the yields was very high, much higher than the simulated yields using the current weather data. Simulated protein concentrations for the first sowing dates for both cultivars was about the same as with the current weather data, while simulated protein concentrations were much lower for the second sowing date for both cultivars and both climate change model projections.
Lincoln results
In contrast, at Lincoln, yields for both sowing dates, both cultivars, and using both climate change projections indicated increased yields over the simulated yields using the current weather data. Variability associated with simulated yields was lower than yields simulated with current weather data. Simulated protein concentrations for the first sowing date for both cultivars using both climate change model projections were about equal to concentrations simulated with current weather data. For the second sowing date, protein concentrations decreased for both cultivars and both climate change projections.
Summary
The models indicate that some regions of the state will become less favorable and some more favorable for winter wheat production. The simple adaptation (a cultivar adapted to a warmer climate and later seeding date) for the climate change projections we used cannot totally compensate for both losses of yield and protein content. If the current grain protein levels and yields are to be maintained in future cultivars, these future cultivars will have to become more efficient in taking up nitrogen from the soil and repartitioning it to the grain. The future will present us with both opportunities and challenges.
Albert Weiss
Professor
Cynthia J. Hays
Research Technologist
Both in the NU School of Natural Resource Sciences
While some of the collection dates have passed, eight remain. At each site, pesticides are accepted at no cost and with no questions asked. Individuals having over 1000 pounds of product are asked to provide a nominal fee for every pound over this amount to cover disposal costs. If you plan to turn-in quantities of 1,000 ounds or more. Leave labels on pesticide containers and handle containers to avoid spills.
Pesticide products in pressurized cylinders, oil, antifreeze, tires, paints, varnishes, thinners, cleaners and solvents will not be accepted.
Collection sites
Pesticides will be accepted at the following sites from 8 a.m. to noon:
Historically, there have been many obstacles to using climate information and weather forecasts, primarily concerns about its accuracy. The good news is that in recent years serious effort has been put into improving the accuracy and reliability of weather and climate forecasts. Now, seasonal forecasts have an average success rate of about 60%, with the rate for daily and weekly forecasts being even higher. In 1997 the first forecast of El Nino was successful. It was widely used and benefitted agricultural producers and resource managers across the nation in many significant ways.
|
Producers already are applying some methods for using seasonal forecasts while minimizing the potential impacts of forecast inaccuracy. These methods have included planting a mix of hybrid seeds with both high and low water usage and yield, and diversifying farm operations to include either forage production or farm animals. For short-term forecasts problems, we can adjust a strategy or repeat an operation. For example, when a predicted rain does not occur, irrigation can be implemented. Allowing for the predicted rain provides a chance to take advantage of the weather and potentially reduce irrigation costs.
Routinely applying climate and weather forecasts as well as strategies to manage related risks can help producers maintain steady productivity in a changing environment. Moreover, because it takes no more work or investment to apply the forecasts than to not use them, the rewards and benefits are obvious.
To develop forecast and information products tied to the needs and uses of producers, the Climate Education and Extension Project (CEEP) was created. It will work with extension personnel and agricultural producers to provide weather and climate forecasts on a variety of time scales and climate products useful for Nebraska. It also will be developing farming strategies that take advantage of seasonal and short-term forecasts with a goal of improving ag profits.
Producers, Extension faculty and agribusiness are invited to attend the first CEEP workshop on April 19 at the University of Nebraska Campus at Kearney to learn more about the project and to talk with faculty about the kind of weather and climate tools they would use. This workshop will introduce major resources of weather and climate forecasts and information products and include illustrations of how Nebraska producers are currently using these resources in their operations.
The workshop is free and will be held from 8 a.m. to 4:30 p.m. and include the following topics: Climate Forecasts and their Interpretations; the Nebraska Weather Monitoring Network (AWDN) and its Products; Applying Weather Data in Irrigation Scheduling; Using Weather/Climate Data to Manage Alfalfa; Strategies for Reducing Adverse Weather Impacts on Ag Production; Integrating Climate Information in Agricultural Resource Management and Planning; and El Nino in 2002 - an Outlook of its Effect on Nebraska's Spring and Summer Rainfall.
The workshop is free, but registrations are required by April 4. For more information about the workshop or to register, visit the CEEP Web site at http://snrs.unl.edu/climate/CEEP_2.pdf, contact Steve Hu at 402-472-6642, or e-mail him at: qhu2@unl.edu.
Current UNL faculty on the CEEP Committee, including several of our Crop Watch contributors, are Hu, Kenneth Hubbard, William Waltman, Roger Selley, James Stack, Andrew Christiansen, Keith Glewen, William Kranz, Gary Hein, and Dean Yonts.
Steve Hu, Climatologist
School of Natural Resource Sciences
|
One way to estimate the value of manure is to use results from on-farm trials to determine the value of the fertilizer replaced and any increase in productivity. Several trials have been conducted by farmers participating in the Nebraska Soybean and Feed Grains Profitability Project in eastern Nebraska.
In one trial conducted by Ron Larsen of Wahoo over three years, 25 tons of beef slurry (10% dry matter) was applied. The manure replaced $42.23 of fertilizer, resulted in $22.50 of added corn production, and supplied additional nutrients valued at $64.02 for a total value of $128.85 or about $5.15 per ton. Consultant assisting with the trial was Tom Vrbka of Wahoo.
The results were similar in a second trial, which was conducted by Dale Hanson and sons of Mead. During the first year of the three-year trial, 27 tons of beef slurry replaced $38.41 of fertilizer, resulted in $10 additional corn production, and supplied additional nutrients valued at $69.14 for a total value of $108 or $4 per ton. Vrbka also assisted with this trial.
Richard DeLoughery, Extension Water Quality Education Coordinator, calculated nutrient values of common manures and found: "For example, one ton of beef feedlot manure can contain over $6 of nitrogen and phosphorus (using current fertilizer prices), plus value from the organic matter and other nutrients. If it is applied at 25 tons an acre, that is over $150 per acre of fertilizer value.
Slurry swine manure from a pit under a confinement building will have nitrogen and phosphorus worth about $7 per 1000 gallons. If applied at 5,000 gallons an acre, it would be worth about $35 per acre."
If your soil is already high in nutrients and has a sufficient infiltration rate that water loss to runoff is not a problem, there may be little short-term benefit to manure. Manure is much more valuable when there is a need to build levels of phosphorus and other nutrients. The value of phosphorus alone in manure typically ranges from $1.90/ton for feedlot manure to $14.70 for broiler litter. Additional value can be gained when there is a need to improve the water infiltration rate as well as the nutrient supply. To maximize profit, manure generally should be applied where soil phosphorus is low or very low, and a cereal such as corn is to be planted.
When calculating the value of manure, you should also consider potential problems with its use.
Charles Wortmann
Extension Nutrient Management Specialist
|
How can producers estimate the value of these biosolids?
Biosolids supply the full complement of nutrients needed by crops, and often help to improve soil biological and physical properties such as the rate of water infiltration. Because of these improvements, crop yield is often more with biosolid application than with fertilizers.
One way to estimate its value is to use results from trials to determine the value of the fertilizer replaced and the increase in productivity. Several trials have been conducted by farmers participating in the Nebraska Soybean and Feed Grains Profitability Project in eastern Nebraska.
In a biosolids trial conducted over four years by Dave and Wayne Nielsen of Lincoln, 45 tons of biosolids were applied. The biosolid replaced $19.42 of fertilizer. It increased yield as compared to fertilizer alone by a total of 17 bu/A corn @ $2.50, 35 bu/A sorghum @ $2.25, and 1 bu/A soybean @ $4.50 for total value of $126 in increased production. The total value can be estimated at $145.42 or $3.22 per ton. Assisting with the trial were Earle Raun, consultant, Keith Glewen, extension educator, and Dave Varner, extension educator.
In a second trial conducted by Burdette Piening of Lincoln over three years, 35 tons of biosolids were applied. The biosolid replaced $15.21 worth of fertilizer. It increased yield as compared to fertilizer alone by a total of 15 bu/A corn for total value of $37.50 in increased production. The total value can be estimated at $52.71 or $1.50 per ton. Ag consultant assisting with the trial was Charlie Hartwell.
In a third trial, which was conducted by Lynn Vinduska of Plattsmouth for three years, 25 cubic yards were applied. The biosolids replaced $34.83 in fertilizer and the total increase in corn and soybean yield as compared to fertilizer alone was $224.83. This gives a value of $10.39 per ton. Ed Penas of Lincoln consulted on the trial.
If your soil is already high in nutrients and has a sufficient infiltration rate, the benefits may not be fully realized in the short term. Greater crop response to applied biosolids can be expected if:
Biosolids are well-regulated under EPA Rule 503 to ensure their safety for land application. Biosolids for land application must pass standards for pathogen levels, concentrations of polluting metals, and for attracting flies, rodents and other disease carriers. The potential for environmental contamination is less if:
Charles Wortmann
Extension Nutrient Management Specialist
Atrazine, glyphosate, paraquat, and combinations with atrazine are the most economical means of controlling downy brome in perennial grasses; however, registration restrictions limit their use. Not all atrazine or glyphosate labels mention control of downy brome in pastures and rangeland. Check labels before using.
The Shotgunr label (EPA Reg. No. 34704-728) (atrazine + 2,4-D) allows its use to renovate existing grass pasture stands. The present label only allows such applications to grassland not in agricultural production (such as CRP) or to renovate existing stands. As of October 2001 grazing or hay removal can begin after two growing seasons have passed after application of Shotgun, according to the EPA. This is the only label that will allow this application. Suggested rate for Shotgun is 1 to 2 quarts per acre on soils with 1% to 2% organic matter and up to 3 quarts per acre on soils containing more than 2% organic matter. A quart of Shotgun contains 0.56 pounds of atrazine and 0.25 pounds of 2,4-D per acre.
Atrazine at 0.5 to 1 quart per acre will control downy brome in pastures and rangeland. On coarser-textured soils the maximum rate for atrazine should be reduced to 0.8 quart per acre to avoid injury to desirable grasses. Atrazine at 0.5 quart per acre applied in the fall may not control downy brome that germinates in the spring. In the spring add atrazine to glyphosate or paraquat to control late emerging downy brome. Big bluestem, bluegrama, buffalograss, indiangrass, little bluestem, sideoats grama, and needle-and-thread are more tolerant to atrazine than crested wheatgrass, smooth brome, switchgrass, and western wheatgrass.
Some glyphosate products are labeled for controlling downy brome in dormant pastures and rangeland. These include Glymix MTr, Glyphomaxr, Roundup Original Glyphosater, and Roundup Ultrar. Other glyphosate products have registrations on pasture grasses that are not adapted to Nebraska such as bahiagrass and bermudagrass. Domestic livestock must be removed before application, and pastures cannot be grazed or harvested for hay for eight weeks after treatments.
Suggested rate for controlling downy brome and many other annual weeds growing with perennial cool and/or warm season grasses with glyphosate is 12 to 16 ounces per acre. Some labels, for instance Gly Starr, may suggest 8 to 16 ounces per acre. Fall applications should be made when good fall growth is present after a hard freeze has killed the top-growth of perennial grasses. Spring applications must be made before perennial grass growth begins in the spring.
Applying glyphosate to perennial grasses before a killing frost or after plants green up in the spring will cause injury. AMS or ammonium sulfate should not be used with glyphosate when treating pastures or rangeland. Apparently, the ammonium sulfate increases injury to the perennial grasses.
Paraquat at 16 ounces per acre will control downy brome in the fall, but will not kill downy brome in the spring if it is well tillered because regrowth occurs from tillers. Paraquat may severely injure some perennial grasses, such as Kentucky bluegrass.
Gail A. Wicks
Extension Weeds Specialist
West Central REC
Robert G. Wilson
Extension Weeds Specialist
Panhandle REC
Preseason grazing will not harm summer grass - provided you finish grazing before new grass shoots get more than a couple inches tall. This usually doesn't occur until late April or early May in southern Nebraska and slightly later further north.
Early, preseason grazing of warm-season grass also removes some old growth from last year which starts recycling nutrients trapped in dead plant tissue. In fact, about the only bad news about early, preseason grazing is you have to get fences and water ready earlier, you need to move animals to the pasture, and you won't completely kill out these weeds in one year.
Bruce Anderson
Extension Forage Specialist
Care of Newly Planted Trees, G1195
Site Preparation: Key to Successful Conservation, G1417
Featured Web site
For National Ag Week the Nebraska Department of Agriculture posted a commentary from Director Merlyn Carlson as well as information on the imporance of agriculture in Nebraska, a children's activity page on agriculture, ag production comparisons and more. The site is at http://www.agr.state.ne.us/photos/02agweek/02agweek.htm.
Nebraska has 54,000 farms and ranches; the average operation consists of 859 acres and average net income per farm ranged from $40,000 to $60,000 during the last four years.
| About Crop Watch | Agricultural News Events | Archives | Markets | Research Ag Links | Weather | Photos Search | Editor Rural Routes | Publications | IANR |
 | ||
| Published by University of Nebraska Cooperative Extension in the Institute of Agriculture and Natural Resources Cooperating with the counties and the U.S. Department of Agriculture | ||
| University of Nebraska Cooperative Extension educational programs abide with the non-discrimination policies of the University of Nebraska-Lincoln and the United States Department of Agriculture. | ||
Sometimes landowners have a choice -- rent land to an established producer or rent to a beginning farmer facing extraordinary start-up expenses. A new state plan aims to even out the risk for landlords by offering a tax break which may benefit beginning farmers. Roy Frederick, NU ag policy specilaist, discusses the plan on 