
March 2, 2001
Welcome back to Crop Watch!This is the first issue of the 2001 publication season for Crop Watch. We're looking forward to producing another great year of timely, research-based information targeted to Nebraska agriculture and fine-tuned to this year's crop situation. Each issue is written by University of Nebraska Cooperative Extension specialists and researchers from across the state. Crop Watch is available in print and on the Web. To order the print version call (402) 472-7981 or use the order form. |
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Reduce nitrogen and maintain yields;
Take credit for residual nitrogen sources
Test soils for nitrates;
Tips for taking quality soil samples
Irrigating corn with high-nitrate water
Planning and placing Bt refuges in corn
Crop insurance subsidies increased; application deadline March 15
Poor germination, shortages plague soybean seed supply
Webcast speakers to address
check-off programs
Farmers to report
on their research
Field update
Women focus on ag marketing
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What nitrogen rate
NU worksheets and spreadsheets help you calculate and compare your nitrogen application options. |
The NU recommendations put producers very close to maximum yields, but at nitrogen rates that are 30 to 50 pounds per acre less than what many farmers apply. At today's prices, the savings easily could add up to more than $10 per acre. Using a realistic yield goal is part of the recommendations. Use a five-year average plus 5%. Our research shows that many farmers use a yield goal higher than that, but fail to reach the yield goal 50% of the time.
NU recommendations indicate that applying 75% to 80% of what was previously applied may actually be the most profitable option, especially at today's nitrogen prices.
When fertilizer prices fluctuate, nitrogen use can be increased or reduced accordingly. Research shows that when corn is $2 per bushel and nitrogen is less than 13 cents per pound or $210 per ton of anhydrous ammonia, it is profitable to add 50 pounds of nitrogen to NU's recommended rate. However, when anhydrous ammonia prices rise above 22 cents per pound of nitrogen or $364 per ton, it is profitable to reduce the recommended rate by 50 pounds. This analysis doesn't include application costs.
Using data from 35 nitrogen demonstrations on sandy soils, average yields were 156 bushels per acre when the total nitrogen applied was 50 pounds less per acre than recommended. At the recommended rate, yields were 162 bushels, and at 50 pounds more than recommended, the yields were 165 bushels. Other researchers have found similar results in other areas of the state. (Many of these demonstration sites were on irrigated fields which may have had high nitrate levels. If your field situation is different, adjust the recommended rate accordingly.)
Reports indicate anhydrous ammonia supplies are limited and the cost of nitrogen, if available, will be near the point where reducing nitrogen by 50 pounds per acre from the recommended rate will be profitable. If prices rise to 30 cents per pound of nitrogen, use 75% of the university's recommendation for nitrogen, then monitor the crop and add more nitrogen by side-dressing if deficiency symptoms appear.
For more information, see the following NU Cooperative Extension NebGuide,
Charles Shapiro
Extension Soils Specialist, Northeast REC
Soil
Soil nitrogen is available to the crop from two pools, residual soil nitrate and nitrogen mineralized from organic matter. Residual nitrate will remain in the soil from previous years' fertilization as well as from mineralized soil organic matter. Nitrate is soluble and mobile in soil and will be distributed throughout the root zone. Sample to a depth of three feet. Since nitrate is mobile, excessive precipitation after the soil sample can reduce the amount of nitrate available. Nitrogen also will be mineralized from soil organic matter. Mineralization rates are influenced primarily by temperature, moisture and the amount of organic matter.
Irrigation water
Sample and test groundwater samples for nitrogen. The amount of nitrogen available depends on the nitrate concentration in the water and the amount of irrigation water expected to be applied.
Manure
Livestock manure can be a major source of nitrogen; however, the nitrogen content of manure is highly variable and can deviate widely from book values. To estimate the amount of nitrogen actually being applied, have a representative manure sample analyzed for ammonium and total nitrogen, and calibrate the applicator accordingly.
To get complete use of the manure nitrogen, it's necessary to incorporate the manure during application. Ammonium is readily lost when exposed to air. If incorporated two days after application, 50-75% of the ammonium-N is lost. If the manure is not incorporated, ammonium nitrogen losses may be 80-95%.
Manure will continue to contribute nutrients for several years. Organic nitrogen becomes available as manure decomposes. The residual supply of manure nitrogen is estimated to be 12-15% at one year and 5% two years after application. For more information on estimating the value of manure, see the following NebGuides:
Legumes
If the previous crop was a legume, NU recommends that fertilizer nitrogen can be reduced by 45 lb/A for corn and sorghum. This is a conservative estimate - generally the soybean nitrogen benefit to a subsequent grain sorghum crop is more than 70 lb/A. If the previous crop was a good stand of alfalfa, plan for 150 lb residual nitrogen per acre.
Charles Wortmann
Extension Soils Specialist
Tips for quality samplesSoil test results are only as good as the sample. Following are a few tips for getting the most accurate results.
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University of Nebraska Cooperative Extension technologists working on the Wellhead Area Protection Project (WAPP), an irrigation and nutrient management demonstration project funded by the Nebraska Department of Environmental Quality, the Upper Big Blue NRD and the Little Blue NRD, are finding increased soil residual nitrate-nitrogen in soil samples from demonstration fields. Crop consultants and soil testing labs in central Nebraska also have reported increased soil residual nitrate-nitrogen levels.
Many of the fields showed levels of residual nitrate-nitrogen twice as high as last year, and some were four times as high. These increases, however are not necessarily typical of Nebraska as a whole. The nitrate levels in soil samples submitted last fall by farmers from across the state varied widely. Levels ranged from 13 lb/A to 240 lb/A of nitrate-nitrogen available for the 2001 crop. These broad variances further reinforce the need for accurate soil testing when calculating nitrogen credits and the need for purchased nitrogen.
Soil testing For most soils, the soil sample should be taken down to three feet, unless crop-rooting depth is limited due to soil conditions such as coarse sand or a high water table. In these cases a minimum depth of two feet may be appropriate.
Once the residual nitrate-nitrogen content of the field is known, a nitrogen credit can be determined. The following example is based on results from a WAPP demonstration site in south central Nebraska. The residual nitrate-nitrogen credit, derived from a three-foot soil sample, indicated there was 100 pounds of nitrogen per acre already available for crop use. If anhydrous ammonia costs are estimated at $325 per ton, the residual nitrate-nitrogen is worth $19.80 per acre. Following University of Nebraska soil sampling guidelines, the projected cost for nitrate-nitrogen soil lab analysis will be approximately $0.20 per acre. This results in a net value of $19.60 per acre. (Actual costs for taking the samples in fields are not included.)
If a soil sample is not taken, a default value of 32.4 pounds per acre is assumed.
Soil analysis For more information on taking and submitting soil samples and for soil sample boxes and information sheets, contact your local Cooperative Extension Office. Samples can be submitted to any certified lab, including the University of Nebraska Cooperative Extension Soil and Plant Analysis Laboratory. (See List of Soil Laboratories) Mail samples to 139 Keim Hall, University of Nebraska, Lincoln, NE 68503-0916. The NU Lab also can be reached by phone at (402) 472-1571; fax: (402) 472-1396; or by Email at SPAL@unl.edu
For more information, the following publications are available in print from your local Cooperative Extension Office or on the web:
Mick Reynolds
Extension
Technologist
Kim Peterson
Communications Coordinator
South Central REC
Applying |
Different concentrations of ground water nitrate were obtained by drilling irrigation wells into two aquifers. One well pumped from the shallow, nitrate-contaminated, sand and gravel aquifer (30 ppm nitrate-N) that provides most of the area's irrigation water, while a second took water from the deeper Ogallala aquifer (0.1 ppm nitrate-N). Water was applied by surge irrigation to a series of quarter-mile long, eight-row strips. Furrow ends were blocked to retain runoff on the field as is customary in the area; however, a buffer area at the lower end of the rows assured that no runoff backed up into the research plots.
Three irrigation treatments included "adequate" irrigation with high-nitrate water, "excess" irrigation with high-nitrate water (to simulate typical practice in the area) and "adequate" irrigation with zero-nitrate water. The adequate irrigation was applied every-other-row with 2-3 inch amounts made according to crop needs. The excess irrigation was applied every-row, about every 10 days. Each irrigation treatment was subdivided into 150 ft-long N fertilizer treatments that ranged from starter-only to 170 lb-N/ac. Nitrogen fertilizer was applied as sidedress NH3 in 1997, and as preplant NH3 with a nitrification inhibitor in 1998 and 1999. Starter was 3 lb-N/ac in 1997 and 1998. We added an additional 20 lb/ac in 1999.
The distinct combinations of growing season rainfall and spring residual soil N resulted in distinct growing environments each year.
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Major differences were seen in residual soil nitrogen after harvest. The residual increased linearly with applied nitrogen, ranging from 20 lb/ac for starter-only to 80 lb/ac at the 170 lb/ac nitrogen rate for the zero-nitrate water and 35 to 125 lb/ac for the high-nitrate water. There was little difference in residual amounts between the two high-nitrate water irrigation treatments.
The 1998 season began with about 60 lb/ac of residual nitrogen. All nitrogen amounts above starter were reduced because of the lack of yield response the previous season. There was more rainfall during the early part of the season so that most residual nitrogen and nitrogen from early mineralization was leached below the shallow root zone of the young plants. The starter-only nitrogen treatment suffered a substantial nitrogen deficit through the six-leaf stage, resulting in significant yield loss. In the high-nitrate water treatments there was no yield response for nitrogen rates above 50 lb/ac, and no response beyond 100 lb/ac for the zero-nitrate water (Figure 1-B). There was no yield difference between adequate and excessive irrigation with high-nitrate water beyond the starter-only nitrogen treatment. Residual nitrogen amounts were smaller than in 1997, because of more early season leaching and reduced nitrogen fertilizer. Amounts ranged from 17 to 53 lb/ac for the high-nitrate water and 15 to 30 lb/ac for the zero-nitrate water.
In 1999 the experiment was placed on plots with only 15 lb/ac residual nitrogen, which in practical terms meant none available for the crop. Rainfall was much above normal during spring and early summer, resulting in a high rate of leaching of both nitrogen from mineralization and from preplant nitrogen. Although we applied extra starter nitrogen, there was major yield loss on the starter-only treatment for all irrigation treatments. In fact, we were unable to obtain maximum yield at any nitrogen rate for the adequate irrigation treatment using either zero or high-nitrate waters because of the loss of preplant nitrogen (Fig. 1-C). The limited amount of extra nitrogen from the adequate irrigation with high-nitrate water was insufficient to make up for leaching losses. In contrast, maximum yield was obtained with only 70 lb-N/ac under the excess irrigation treatment with high-nitrate water. While much of the excess irrigation water moved quickly through the root zone, the crop was able to extract enough additional nitrogen to meet its needs. After harvest residual nitrogen amounts were 15 to 25 lb/ac.
Conclusions
This study confirms that where irrigators are using high-nitrate water on medium to finer textured soils, nitrogen from irrigation water can replace part of the crop's nitrogen needs. With 55+ lb/ac of residual nitrogen and limited to average early season leaching, the crop in our study was able to meet more of its nitrogen needs from residual nitrogen and mineralization than is usually assumed in calculating nitrogen fertilizer needs. Under these conditions and adequate irrigation with high-nitrate water, the amount of irrigation water nitrogen used by the crop ranged from 50% for starter-only to about 10% with 170 lb-N/ac. Uptake from excess irrigation was only 10-15% for fertilizer amounts above starter. This is because most of the water in excess of the moisture deficit drained from the root zone in two to three days. Excess irrigation was advantageous only in 1999 when much of the mineralized nitrogen was lost to early season leaching and there was essentially no residual N. In this case up to 50% of the nitrogen in the water was used by the crop when only starter nitrogen was applied; however, use efficiency declined linearly to 10% as nitrogen increased to 170 lb/ac.
Producers furrow irrigating on medium to fine textured soils with 25-30 ppm nitrate-N water are probably safe in reducing nitrogen fertilizer levels 10-20% below recommended amounts this year provided that residual nitrogen at planting time is 40+ lb/ac. If there is an extended rainy period any time before milk stage, they should be prepared to irrigate a wet field every 10-14 days to replace nitrogen lost to leaching. The key is to use high-nitrate water to replace nitrogen taken up by the crop or leached out of the root zone by rainfall. Under center pivot irrigation high-nitrate water can also reduce the nitrogen fertilizer requirement. However, most pivot irrigators will normally apply less water than furrow irrigators during the first six weeks of the irrigation season when corn is in the rapid nitrogen uptake period. While efficiency of nitrogen extraction from irrigation water may be higher under pivots, there will be less applied. Nitrogen uptake from the water will decline to a low level if enough fertilizer nitrogen is applied to fully meet crop needs.
Darrell Watts
Biological Systems Engineer
There are several reasons that farmers should comply with resistance management requirements. First, and most importantly, compliance will slow the development of Bt resistant corn borers and preserve Bt as an effective pest management tool for the future. Second, compliance is part of the grower agreement when buying Bt transgenic corn seed. And finally, if the Environmental Protection Agency feels that compliance is not high enough, they could implement regulations to restrict the use of Bt corn.
Management strategies have been designed to prevent or at least delay the development of resistance. Corn borer larvae that feed on Bt corn are exposed to the Bt toxin at much higher levels than from use of foliar Bt insecticides, such as Dipel or M-Peril. Also, corn borer larvae are exposed to Bt toxin for much longer times when feeding on Bt corn. Under this high level of selection pressure, the threat of resistance development is high.
Resistance management for ECB and Bt corn revolves around the use of refuge plantings. A refuge is any ECB host plant (e.g. non-Bt corn, potatoes, and some weeds) not producing Bt proteins or not being treated with conventional Bt formulations. The purpose of the refuge is to supply a source of Bt-susceptible ECB that could mate with resistant ECB potentially emerging from nearby Bt corn. In current resistance management strategies the refuge must be non-Bt corn because other ECB host plants do not produce enough moths. Specific resistance management information will be a part of each corn seed bag label. Be sure and discuss resistance management with your seed dealer.
The resistance management requirements for 2001 are the same as last year:
Figure 1 presents some general within field refuge configurations.
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Refuge considerations
Figure 2 shows two examples of how you might establish a refuge for a Bt cornfield.
Figure 2. Examples of refuge design using a 30-inch row spacing and 16-row planter.
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Tom Hunt
Extension Entomology Specialist
Jerry Echtenkamp
Extension Technologist
Both at the Northeast Research and Extension Center
Compare rates on-lineThe USDA Risk Management Agency's web site is a rich resource of information and tools to assess which insurance options are right for an individual operation.The site features an online calculator to compare options; list of crop insurance agents in Nebraska, background on the changes for this year, and more technical actuarial information. |
For farmers who already have multiple peril crop insurance policies, coverage will continue into this year if no changes are made with their crop insurance agents.
Increased subsidies
The government-paid premium subsidies for crop insurance have been increased substantially, particularly at the higher coverage levels. The other significant change is that the subsidy level, as a percentage of the full risk premium, is now the same for both the regular yield-based APH multiple peril crop insurance (MPCI) and the Crop Revenue Coverage (CRC) at any particular coverage level. For example, for the 70% coverage level, after the full risk premium is calculated, 59% is deducted and the farmer pays 41%.
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The two most commonly purchased forms of crop insurance in Nebraska are multiple peril crop insurance and crop revenue coverage.
Multiple Peril Crop Insurance (MPCI) provides comprehensive protection against losses due to natural causes such as drought, excessive moisture, hail, wind, frost, insects, and disease, providing protection against low yields, poor quality, late planting, replanting costs and prevented planting.
Crop Revenue Coverage (CRC) - provides revenue protection based on price and yield expectations by paying for losses below the guarantee at the higher of an early-season price or the harvest price.
Actual Production History (APH): Each insured unit has its own yield for coverage purposes. This figure is based on a minimum of four years of actual production history and a maximum 10-year moving average of actual yields. A number of low yield years can reduce the production history and, hence, future coverage. Now producers can substitute a yield equivalent to 60% of the county yield for each year that the actual yields fall below that yield. This adjusted figure will then be used to calculate coverage. The true history using the actual yields will still be used to calculate the premium.
Prices for 2001
The prices to establish the revenue guarantees for the CRC program are based on the February averages of the DEC futures contract for corn and the NOV contract for soybeans. Grain sorghum is 95% of the corn price. As this article goes to press, the corn price is about $2.45 and the soybean price is about $4.60. An official announcement of the prices will be made after March 1.
These prices set up an interesting relationship. The CRC price for corn is considerably higher than the APH price and the converse is true for soybeans. Since the advantage of the CRC program is to complement the forward pricing of the crop, growers should look closely at their marketing plan for corn and grain sorghum and how CRC could provide a backstop to price grain before harvest. Soybean is a different situation with the APH price at $5.26 and the CRC price below the loan level.
| Prices used to calculate premiums and indemnities for the regular APH-MPCI program in 2001 | |
| Corn | $2.05 per bushel |
| Grain Sorghum | $1.80 per bushel |
| Soybeans | $5.26 per bushel |
Units
Growers typically prefer to have their insurance units as small as possible to maximize protection. With the CRC program, "enterprise" units are available which allow grouping all the acreage of a particular crop grown in a county to be aggregated together into one unit, regardless of the ownership or share situation.
The benefit is that a premium discount is offered for an enterprise unit. The discount is typically 10% to 20%, compared to the premiums for separate units. Growers need to look at their individual situations and compare the increased risk they assume with the enterprise unit compared to the reduced cost.
Doug Jose
Extension Farm
Management Specialist
"We have seen a huge range of germination percentages this year, from above 90% to as low as 30%," he said. "There are some good seed lots out there, but there is also some seed that will have to be discarded."
The smaller seeds typical of the 2000 crop also were more apt to be sorted out during processing, said Gary Cross, foundation seed manager for NU's Institute of Agriculture and Natural Resources. "This year we are seeing 25% to 30% cleanout compared to around 10% most years."
All these factors are contributing to a shortage of quality seed.
"We have about half of the soybean seed that we planned to have available for sale this year," said Ken Anderson, a marketing manager with NC+ Hybrids. "We have lowered our germination standard from 90% to 85% to increase supplies and we are still short. Some other companies have even lowered the standards to 75% or lower."
Farmers considering a shift from corn to soybeans may be disappointed in the limited types of seed available. While the popular Roundup Ready beans may be sold out, conventional and STS varieties are still good options for Nebraska farmers, Knox said.
Planting rates
Planting rates will need to be adjusted to account for the smaller seeds and poorer germination. NU specialists recommended a planting rate of 150,000 live seeds per acre to have 100,000 mature plants per acre at harvest.
"It is also important to note that the germination percentage shown on the bag is from a warm germination test, not a cold stress test, so it may be a high estimate of the number of seeds that will germinate in cooler field conditions," said Jim Specht, an NU crop scientist.
To find the correct planting rate, divide the desired number of live seeds per acre by the decimal equivalent of the germination percentage. For example, for seed that has 75% germination, divide 150,000 by .75. For 150,000 live seeds per acre with this seed, farmers would need to plant 200,000 seeds per acre.
For more information, consult the Cooperative Extension NebGuide Soybean Seeding Rates, G99-1395.
Heather Corley
Newswriter
IANR News and Publishing
The Cooperative Extension program will be live from 3 to 3:45 (CDT) on the University of Nebraska Rural Routes web site and will be archived for viewing after 5 p.m.
"The defeat of the pork check-off program has sent ripples through the other check-off operations," said Jim Kendrick, NU marketing specialist emeritus and host of the program.
"The check-off programs play key roles in market development and research of their commodities; however, there is certainly dissatisfaction among some producers," Kendrick said. "We'll talk about the issues and what is or can be done to help producers with marketing and developing better crops and livestock," said Kendrick.
Appearing on the panel with Kendrick will be Sally Atkins, executive director, Nebraska Beef Council; Vic Bohuslosky, executive director, Nebraska Soybean Board; Steve Cady, executive director, Nebraska Pork Producers Association; Roy Frederick, NU public policy specialist; and Don Hutchens, executive director, Nebraska Corn Board.
Results from 17 research trials conducted in 2000 will be discussed at the NSFGPP annual meeting March 12 at the Agricultural Research and Development Center near Mead. (View the research topics and cooperators set to be discussed at the annual meeting.) The meeting, which is open to the public, will begin at 9 a.m. and conclude mid-afternoon; registration is required to provide a lunch count. The program also will be available via satellite. During the luncheon Dr. Darrell Nelson, dean and director of the UNL Agricultural Research Division, will discuss research being conducted by the Institute of Agriculture and Natural Resources.
The Nebraska Soybean and Feed Grains Profitability Project is in its 10th year. To view research results or learn more about the program and how to participate in it, visit the NSFGPP web site or contact Extension educators Keith Glewen, Saunders County, at (402) 624-8030 or Dave Varner, Dodge County, at (402) 727-2775. To register for the March 12 meeting, contact either of the educators or call the ARDC at (402) 624-8000.
The University of Nebraska's Women in Ag Marketing Curriculum teaches women basic and advanced marketing skills. The curriculum "starts from the ground up" to give beginners a solid foundation for future lessons. Attendees with previous marketing experience benefit from building confidence and polishing their skills.
The program is divided into four sessions to be held at the Kearney Holiday Inn March 13-14, June 12-13, Aug. 21-22 and Nov. 14-15. Participants are encouraged to attend all sessions.
The curriculum covers what people need to know about the agricultural markets, about their operations and about themselves. Lesson topics include basic marketing terms, contracts, prices, basis, cost of production, cash flow, risk attitudes and goals.
For information about the slate of upcoming speakers or to register, call (800)535-3456. Fees are $125 for the first workshop attended and $100 per each following workshop, or $375 for all four workshops if paid before the first workshop. Hotel accommodations are available at the Kearney Holiday Inn, (800)248-4460.
The Women in Ag Marketing Curriculum is sponsored by the Department of Agricultural Economics and Cooperative Extension in NU's Institute of Agriculture and Natural Resources.
Deb Rood
Program coordinator
NU Department of Agricultural Economics
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