Northcentral

The start of the season has been mixed. Parts of the Northcentral region are showing generally good crop growth, while other areas are off to a slow start and have had to be replanted. All of these factors add up to an increased need to focus on nutrients. In particular, it will likely be worthwhile to walk through fields on occasion and look for signs of nutrient deficiencies. An occasional plant sample can also be helpful for either confirming deficiencies associated with symptoms or finding areas that are deficient, but not showing visible symptoms. For corn, end of season stalk nitrate tests taken in a few fields can help evaluate if there was enough nitrogen applied during the season. While scouting and tissue tests are not commonly done for many row crops, changes in the nutrient management situation make such additional measurements more important than ever.

As in the 2006 season, good conditions prevailed at seeding time across much of the Northeast. Corn and soybeans have emerged well, slightly earlier than last year, and further ahead of normal. Wheat and hay are also ahead of normal. Wheat crop condition is poorer than normal in Ontario and in Ohio.

Environment Canada predicts a warm summer for the extreme southwest of Ontario, Eastern Ontario, and Quebec, with cool to normal temperatures in Atlantic Canada. Summer precipitation forecast for this region is mostly below normal.

Many factors affect availability of nitrogen (N) from the soil, from manures, and from previous crop residues. Mineralization rates, leaching and denitrification losses, and volatile losses of ammonia are all controlled by the weather. A soil nitrate test this month will be very helpful—but make sure the corn is at least six inches tall before taking it. Cornell University provides advice based on real-time weather data for interpreting this soil nitrate test. Taking account of the weather is an important component of N management. Ontario corn N recommendations take into account many factors – check out the N Calculator at www.gocorn.net

Upcoming Events:

InfoAg 2007, July 10-12, 2007 at the Crowne Plaza Convention Center in Springfield, Illinois. http://www.infoag.org/2007

When is Top-Dressing of Nitrogen a Profitable Investment?

It is usually more effective to apply the majority of nitrogen (N) fertilizer a crop requires before or at seeding, but application of additional N after a crop has emerged can at times improve crop yield and or crop quality. Below are three possible situations when this can be a profitable investment:

1. The potential crop yield increased due to better than expected growing conditions. This usually happens when moisture conditions are poor before or at planting and lower than normal fertilizer rates are applied. Subsequently, abundant additional moisture is received soon after planting. In order to achieve the increased potential crop yield more N is needed.
2. There is an excess of moisture received that can cause a loss of N from the soil. In sandy textured soils this can be due to leaching of fertilizer N below the rooting depth of the crop, or in heavier textured soils there may be losses of nitrate (NO3 -) due to denitrifcation and the associated emissions of nitrous oxide (N2O) or di-nitrogen (N2) to the atmosphere in poorly drained fields.
3. An N deficiency is observed in a portion of a field after the crop has emerged and grown for a short period of time. An application of N fertilizer can help correct the shortage of N.

Top-dressing can be done using a granular or liquid N source depending on availability and cost. Application of N to increase yield for a spring-seeded crop should occur at an early growth stage (e.g. before stem elongation in a small grain cereals). Later applications (e.g. after stem elongation) may not increase yield and may only have an effect on increasing the protein level of grain. The surface applied N needs to move into the soil to reach the roots of the crop with moisture from precipitation or an irrigation application. Liquid N applications of urea ammonium nitrate solution (UAN, 32% or 28% N) is best applied as a dribble surface band to minimize the extent of leaf burn. Consideration can be made to use a urease inhibitor for either granular urea (46-0-0) or UAN if warm conditions without a precipitation or irrigation event are not expected within a week of application.

Effective May 1, 2007, Dr. Tom Jensen is the Northern Great Plains Region Director for IPNI. He succeeds Dr. Adrian Johnston, who is now the IPNI Asia Group Coordinator. Both are located in Saskatoon. A news release announcing the appointment of Tom Jensen to this new responsibility can be found by linking to the News Archives at the home page of the IPNI website (www.ipni.net). Feel welcome to contact Dr. Jensen by e-mail at: tjensen@ipni.net.

There has been no shortage of rainfall across most of the region this spring. The latest Palmer Drought index shows none of the major production regions in drought, although, as one might expect, some parts of the western reaches (western Kansas and Nebraska, and eastern Colorado) are somewhat drier than the central and eastern part of the region. Overall, top- and subsoil moisture is far better than at this time last year. This sets the stage for at least a start on a good production year. The good moisture situation is not without its negative consequences, though. For example, delayed harvest in some cases is resulting in over-mature hay and reduced forage quality. Delays in planting of some crops such as corn may ultimately compromise yields. On the other hand, delays in planting of corn and cotton in some areas have resulted in increased planting of grain sorghum.

One consideration that comes with this year’s wet spring is the question of nitrogen (N) loss due to leaching, denitrification, or both. The ultimate question is whether additional N is needed to compensate for any such losses. This is a difficult question to answer with certainty, but there are a few things to keep in mind when making this decision. The following observations, derived from the June 6th KSU Agronomy e-Update, may be helpful in making determinations where corn is off-color and/or stunted

• The profile N soil test is not a reliable tool for assessing soil N supply at this time. Soil nitrate-N samples collected from growing crops will generally indicate less available N than expected. This is because some N has likely been incorporated into an easily mineralizable N pool (temporary immobilization, incorporation in root mass, etc.) that is not reflected in the soil nitrate-N test.
• While some N loss through denitrification may have occurred, not all of the N will have denitrified even though the corn may show N deficiency symptoms. As soils warm and dry, the root system will develop more extensively and will likely find available N on its own.
• Supplemental N needs for individual fields will vary, depending on how much N was previously applied to the crop and what the remaining yield potential is. If yield potential has been reduced, then total N requirements will also be reduced. Potential yield loss is difficult to estimate, but a good starting point might be about one bu/A for each day the crop development is delayed.
• If additional N is to be applied, it should be done as soon as possible. Also keep in mind that rainfall will be needed to move surface-applied N into the root zone. It is difficult to say how much, if any, additional N needs to be applied. If additional N is going to be applied, our (KSU) estimate would be about 30 to 50 lb N/A for most situations (in Kansas) this year.
• There are several application methods that can be utilized at this point in the season. For irrigated corn fertigation is the obvious choice. For other situations, subsurface application between the rows will provide the most consistent results. However, if knife application does not fit a particular situation (e.g., corn is too big) there are other options. Dribble (band) application of UAN to the soil surface between the rows is the next best option in terms of consistency. Application of UAN via drop nozzles below the crop canopy and broadcast urea are next. Broadcast UAN across the top of the crop canopy is the least preferable method since significant leaf burn is likely.

Finally, make sure that the cause of any stunting and off color corn is actually N and not potassium (K) deficiency, especially in reduced and no-till systems. Nitrogen deficiency symptoms show-up on the lower leaves first, with the leaves yellowing from the leaf tips back down the mid-rib in an inverted ‘V’ pattern. Potassium deficiency also develops on the lower, older leaves first, but causes the leaf tips and margins to “fire” and die. These (N and K) deficiencies often do not occur uniformly across the whole field, but rather in irregular patterns.

The major story in the Southeast this summer is the drought. As illustrated in the figure below, every state in the region has been affected by dry weather.

Missouri is in pretty good shape, while Arkansas, Louisiana, and most of North Carolina are abnormally dry. The remainder of the region is experiencing severe to extreme drought with northern Alabama being the worst. All of the dry weather, as well as the Easter freeze, have taken their toll on many of the crops in the region.

The weather has been especially unfortunate considering all of the additional acres of corn that were planted in the region this year. The condition of the crop tends to follow the moisture availability. Alabama is reporting 87% of the corn acres as poor to very poor, while Georgia rates about half of their crop in those categories. The remaining states are in the fair to good category with Arkansas and Louisiana reporting >15% of the corn as excellent. North Carolina State University Cropping Specialist, Dr. Ron Heiniger, indicates that “ Corn is hurting on sandy, drought-prone soils, but 90% of our acres are holding up okay. We need at least one good, general rain to take us over the top. If it doesn’t come in the next week, we could see reduced yields."

Cotton growth has followed the same trend as corn in the Southeast. Alabama and Georgia are experiencing poor to very poor crop conditions while 50 to 75% of the cotton in the other states is rated good to excellent.

A sad story with somewhat of a happy ending is the Georgia peach situation. What started out as a promising crop was punished by the Easter freeze leaving less than 50% of the crop that would make it to harvest. The good news for growers is that the early crop is bringing prices 30 to 40% higher than last year. The good news for consumers is that due to the drought, the fruit is less diluted by water, which increases the sweetness of the peach. Typical soluble solid content (the measure of sweetness) is around 10%. This year, Georgia peaches contain 15 to 17% soluble solids.

One final note for the update is that, as you might have noticed, Dr. Cliff Snyder’s picture no longer appears on this webpage. Press releases addressing Cliff’s appointmnet to Nitrogen Program Director and Dr. Steve Phillips’ appointment to Southeast Director can be found by linking to the News Archives from the homepage of the IPNI website. As a reader of the Southeast Region Update, feel free to send any comments or suggestions related to content you would find useful or would like to see posted on the website or in future updates to sphillips@ipni.net.

Good news for Western Agriculture: The USDA recently published a list of the best food sources for supplying antioxidants. Of their top-rated foods, many of them are grown in the Western Region. Beans, fruits, potatoes, and nuts topped the list of foods that are thought to fight cancer, heart disease, and Alzheimer’s disease.

The earlier hope for a good supply of irrigation water dried up during the past few months as a warm, dry spring rapidly melted the snowpack that is relied upon to provide moisture through the summer. The four key components of a good water year include the snowpack, soil moisture, stream flow, and reservoir storage. Much of the western U.S. is again experiencing various degrees of drought.

In California, where winter snowpack in the Sierra Nevada range was only 27% of normal this year, plentiful runoff from last year's snows filled many reservoirs, so shortages are partially off-set. But another dry winter would severely strain water supplies. Twelve extremely dry years have devastated Arizona's water supplies, as well as the native habitat and wildlife. A court-mandated cut off of irrigation water for over 16,000 acres in southern Idaho was caused by dry conditions.

The severe dryness experienced in California and Arizona has spread into several other Western states. On the Colorado River, which serves as the water supply for 30 million people in seven states and Mexico, the Lake Powell and Lake Mead reservoirs are only half full and unlikely to recover for years.

Responding to these water shortages continues to be a challenging proposition, prompting reexamination in crop selection, field management, irrigation methods, fertilization practices, and production decisions required to squeeze out the maximum benefit from every drop of water.