By Darryl Warncke... Recently, I have talked with a number of people that have observed plant growth problems in corn. Fortunately, some of these had taken both soil and plant tissue samples from the problem area and the good area. In each of these cases, the soil in the poor growth area was quite acidic, pH in the 5.0 to 5.4 range. Available soil nutrient levels were generally adequate.

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By Darryl Warncke... Soil nitrogen test results so far this year have indicated that less available N is present in the soil than expected, especially in fields where manure has been applied. This may be partially the result of the heavy rains and the cool soil temperatures.

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By Darryl Warncke -- With the continued high price of potash many farmers are considering cutting back on the amount that is applied. In making decisions about how much potassium to apply or how much one can cut back, it is very helpful to have soil test information indicating the available potassium (K) status of the various fields being farmed.

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By Christina DiFonzo... Avipel seed treatment (formerly Avitec) is available again in 2009 to repel sandhill cranes in field and sweet corn planted in Michigan, as well as Wisconsin and Minnesota. The active ingredient in Avipel is 9-10 anthraquinone, a natural plant compound that birds find distasteful. The birds detect the treated seed and avoid feeding on the corn.

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By Darryl Warncke... The “maximum return to nitrogen” (MRTN) approach for recommending nitrogen for field corn is based on numerous nitrogen response studies across the corn producing areas of Michigan. The MRTN recommendation suggests a nitrogen rate that will most often provide the best economic return for the investment in nitrogen fertilizer.

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By Darryl Warncke... A new growing season brings lots of opportunities for farmers to purchase products with many exciting claims. Michigan’s fertilizer law requires that when the nutrient content of a material is stated on the label, the company is guaranteeing that is the minimum amount of the nutrient mentioned.

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By Darryl Warncke... Having current information about the soil pH and available soil nutrient levels is the passport to effective and economical use of nutrient inputs. With the cost of phosphorus and especially potassium remaining high relative to the value of the corn, soybeans and other fields, it is important to understand the response of crops to nutrient additions in relation to what is available in the soil.

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By Fred Springborn... The high cost of fertilizer this year has everyone looking for ways to use it more efficiently and to use no more than necessary. One way to be sure that you are getting the most for your fertilizer dollar is to apply fertilizer as uniformly as possible.

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Pull out your soil tests and use the following information to assess phosphorus and potassium levels along with your 2009 crop plan to determine where fertilizer will benefit, and where you can save money on nutrients without sacrificing yield. The following charts will help to assess your current soil test levels, showing you where your test values are within the ranges, and help you decide how risky reducing fertilizer will be.

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Hopefully you have experienced a year when corn yields exceeded the nitrogen applied. Soil N can provide as much as half of the total N available to the crop. (Camberato et al., 2008.) Rain and sunlight are often the two most sought after resources for high yields, and when these two resources are abundant and timely, plants seem to find the additional nutrients to exceed yield expectations.

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The economic risk of applying too much nitrogen (N) on corn is just as dramatic as applying too little. In 2004, university agronomists from the North Central region began a project to determine maximum agronomic production of corn at the most efficient economic level.

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A word to the wise: question everything these days. Our reasoning powers that worked in the past are strained today. Farmers used to watch the Chicago Board of Trade for commodity prices; today they watch the price of gas at their local fuel station to gain some sort of rationale for how much fertilizer will cost and what the price of grain will be in the coming year.  While change may be risky, not changing may be even more risky.

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Kurt Thelen...Manganese (Mn) deficiency is the most common crop micronutrient problem in Michigan, particularly in soybeans and wheat. The availability of manganese to the plant generally decreases as soil pH levels increase. Consequently, soybeans grown in the calcareous soils of Michigan’s Thumb area and in the lake-bed soils in Michigan’s southeast Lower Peninsula historically have been found to be deficient in manganese. When possible, producers in these areas prefer to tank-mix manganese micronutrient solutions with foliar applied herbicides to eliminate an extra trip across the field.

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Carrie Laboski...Many soils are saturated and some fields have had or still have standing water in all or part of the field. The million dollar question is: How much nitrogen loss should I expect from denitrification or leaching and what should I do about it? I’ll discuss how to evaluate the potential for nitrogen loss and corrective measures that may be taken.

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Darryl Warncke...Nitrate testing of soil is an excellent and inexpensive way of evaluating the available nitrogen (N) status of your soil. Nitrogen available in the soil is nitrogen that does not need to be purchased. Michigan State University research and demonstration studies have shown that many farmers could reduce their N fertilizer application rate on corn without risk of reducing yields if they used the nitrate soil test. Nitrate testing also helps to prevent over-use of N fertilizers.

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Darryl Warncke...Increasing worldwide demand for nitrogen, phosphorus and potassium has brought about significant increases in the costs of these materials for the 2008 growing season, especially potash. The supply of potassium may also be limited. Faced with this situation, farmers may have to make decisions on how to get the best return from the fertilizer they are able to purchase. Following are some suggestions:

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Darryl Warncke...The price for potash will be considerably higher this year than last year and supplies will be tight. Potash may be allocated based on past use. This is the result of an increasing worldwide demand for potash. Faced with this situation, farmers need to evaluate how they can best use the funds they have allocated for fertilizer inputs. Soil test results are an excellent guide for deciding how much lime, nitrogen, phosphorus and potassium to apply on each crop in each field. Collect soil samples and test as soon as conditions permit or work from recent soil test information, within the last 2 to 3 years.

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Christina DiFonzo...With the high cost of fertilizer this season, many producers are making decisions about how much to purchase, how much to apply, and which fields to treat. As you make these decisions, consider that insects as well as plants are affected by fertilization.

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Darryl Warncke...The change from recommending nitrogen (N) based on expected yield to recommending N based on economic return is quite significant. To adapt to this change will take time and some on-farm N rate evaluation by farmers to become comfortable with these new recommendations. In making this change, farmers may want to use the higher recommended amount in the “Maximum Return to N (MRTN)” range in Table 1.

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Darryl Warncke...With the significant increases in costs of phosphate and potash fertilizers since last season and with tight supplies, some reflection on recommended rates is in order. MSU’s recommendations for phosphate (P2O5) and potash (K2O) are based on the buildup and maintenance approach. In this approach, the most important soil test value is the critical value (CV).

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Darryl Warncke...Nitrogen plays a significant role in the growth, development and yield of corn. From the mid-1900s until present time, supplemental inputs of nitrogen through various nitrogen sources, especially legumes and manufactured nitrogen fertilizers, have contributed greatly to improvement in corn yields in Michigan.

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Darryl Warncke...Increasing global crop production, especially in China, India and Brazil, as well in the United States is increasing the demand for fertilizer nutrient inputs. The following are a few observations based on a presentation by Dr. Mike Rahm (Vice President for Marketing with Mosaic Co.) at the Canadian Fertilizer Conference in August. Demand for nitrogen will continue to increase, but the supply situation is expected to be improved.

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Sieg Snapp and Lowell Gentry...Drought and hail storms have inflicted low and variable corn yields on farmers throughout Michigan. This brings up the perennial question, what happens to nitrogen after corn is harvested? Significant amounts of nitrogen may remain behind in a low production situation. Understanding the fate of nitrogen from fertilizer, manure, crop residues and from the soil is challenging. The complexity of the nitrogen cycle is an active area of research where new lessons are being learned all the time and added to proven knowledge.

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Kurt Thelen...The dry conditions of the 2007 growing season to date have many wondering if they have enough soil moisture to finish out their corn and soybean crops. A few simple calculations can give us a pretty good idea whether or not we have a chance of making it to the finish line. For starters, we know that a 150 to 200 bushel corn crop or 50 to 60 bushel soybean crop require approximately 20 to 24 inches of water.

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Mike Staton...Nitrogen fertilizers are expensive and may become unavailable to your crop. Because of this, corn producers will need to manage nitrogen fertilizer carefully to remain profitable in 2007. Here are some strategies for getting the most from your investment in nitrogen fertilizer.

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Darryl Warncke...Placement of fertilizer in the seed furrow (pop-up) or 2 inches below and 2 inches (2x2) to the side of the seed can enhance early plant growth, especially in cool soil situations. Soils tend to warm more slowly under no-till and reduce tillage systems where there is more plant residue. At a 2x2 placement, there is minimal risk of any plant injury. Placement of fertilizer directly below the seed increases the injury, especially with limited soil moisture or with some fertilizers that may release volatile ammonia, such as ammonium thiosulfate.

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Ron Gehl...The escalating prices of N fertilizers and concerns regarding N fertilizer supplies have many producers questioning the potential benefits of N fertilizer additives, particularly nitrification and urease inhibitors.  Extensive research on these types of products has been conducted throughout the North Central region for many years, with results generally indicating that effectiveness is reliant on many factors, including N source, timing, soil type and tillage.

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Darryl Warncke...Good news, the price for corn, soybeans and wheat went up significantly since 2006. This is a result of the high demand for corn to produce ethanol and many other products. Corn acreage for 2007 is predicted to increase greatly, which increases the demand for fertilizer nutrients. Hence, the bad news, fertilizer prices have increased greatly, especially nitrogen. In a separate article, Dr. Gehl is addressing nitrogen fertilization of corn.

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High fertilizer prices got you down? A newly reformatted worksheet from Michigan State University Extension (MSUE) may help.

The Manure Haul Spreadsheet, introduced in the early 1990s, has been updated to help producers figure the cost of hauling manure to fields farther down the road, a practice that may take the sting out of high nitrogen prices.

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Darryl Warncke...As corn grain has or soon will reach black layer, corn growers should consider using the stalk nitrate test to evaluate their nitrogen management program. Even though the stalk nitrate test is post-mortem (end-of-season) it can be useful for long-term adjustment of N management practices. The nitrate N concentration in the lower portion of the corn stalk at the time grain black layer is formed is a good indicator of the nitrogen status the crop experienced throughout the growing season.

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Kurt Thelen and Mark Bernards...Manganese (Mn) deficiency is the most common crop micronutrient problem in Michigan, particularly in soybeans and wheat. The availability of manganese to the plant generally decreases as soil pH levels increase. Consequently, soybeans grown in the calcareous soils of Michigan’s Thumb area and in the lake-bed soils in Michigan’s Southeast Lower Peninsula historically have been found to be deficient in Mn.

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Darryl Warncke and Jon Dahl...Results for the PSNT (Presidedress Soil Nitrate Test) show significant nitrogen credit can be taken to reduce the amount of nitrogen to apply in about one-third of the samples tested by the MSU Soil & Plant Nutrient Lab. There is a moderate credit for another one-third and for the other one-third the credit is rather low.

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Darryl Warncke...After the rains of this past week many are concerned about the availability of applied nitrogen. Answering this concern is a bit challenging. The good news was that the soils were actually quite dry prior to the rains, so they were able to absorb much of the initial water. However, many areas of Michigan have received more than 3 inches of rain in a few days. Sandy soils are only able to hold 1.0 to 1.75 inches of water per foot of soil whereas loam soils hold 2.5 to 3.0 inches per foot and clay loam soils hold nearly 3.75 inches per foot of soil.

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Darryl Warncke...Are supplemental micronutrients needed in field crop production? In Michigan boron (B), manganese (Mn), and zinc (Zn) are the ones of most importance. There is good information about micronutrient needs for Michigan in MSU Extension bulletins E-486 and E-2904. There are a number of ways to determine whether or not certain of the micronutrients are needed. Knowing the responsiveness of the crop being grown to these micronutrients and the soil conditions where a deficiency is likely to occur can be helpful.

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Darryl Warncke...The presidedress soil nitrate test (PSNT) provides information about the mount of nitrogen available in the soil. Guidelines for N credits associated with the PSNT in Michigan are based in soil samples taken to 12 inches deep. Since nitrogen release (mineralization) from soil organic matter and plant residues in on ongoing process, collecting PSNT soil sample as close to sidedress time as possible gives the best information about the appropriate N credit.

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Mike Staton...Nitrogen fertilizers are expensive and may become unavailable to your crop. Because of this, corn producers will need to manage nitrogen fertilizer carefully to remain profitable in 2006. Listed below are some strategies for getting the most from your investment in nitrogen fertilizer.

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Kurt Thelen and Terry Shulz...Nitrogen fixation is a result of the symbiotic relationship of Rhizobia bacteria and soybean plants. These bacteria fix atmospheric N 2 into the NH 4 form, which is useful to the plant. In return, the plant provides the bacteria with carbon photosynthesis products (dicarboxylic acids), which the bacteria use as food. Establishing rhizobia or inoculation in a field that has never grown soybean is needed to ensure nitrogen fixation.

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