Posts By: Midwest AgCenter

Below are the results for Dubuque and Madison, comparing last year for the same time period, and the norm based on the 30 year average.

GDU (Growing Degree Units)

Instead of the old saying “Knee high by the 4^th of July”, this year, we’ll be seeing tassels by the 4th of July!! Earlier planting in 2018 contributed more to this, than Growing Degree Days did.

With the corn crop being further ahead this year, be on the lookout for diseases forming in corn. A foliar application of fungicide at tassel may be justified. A fungicide application made between VT and R1 have shown on average 11-14 bu. increase per acre.

When enquiring whether a fungicide application is necessary, consider the following criteria:

1. Disease history: Low-lying fields or fields with a history of disease are more likely to respond to a fungicide.
2. High yield history: High yield fields are more likely to show an economic response.
3. Hybrid resistance: The lower the genetic resistance to gray leaf spot, northern corn leaf blight and anthracnose, the more potential for an economic response.
4. Crop rotation: Corn following corn tends to harbor more disease inoculum.
5. IPM (Integrated Pest Management) corn diseases are just starting to appear, especially in no-till corn on corn fields. Fields that already show 5-10% visible disease may have a higher risk of further development.
6. Fertility: Low K levels and compacted soils could exacerbate disease effects on lodging and yield. If the field has poor fertility the likelihood of disease invasion is higher.

If one or more of these criteria apply to your situation, then a fungicide application may provide an economic return. Give Tom, Dan, Andrew, Mark or Kevin a call to help with making the best decision for your farm.

-Kevin Knudtson

             In recent studies, foliar fungicides have been effective in managing many foliar diseases in soybeans and has proven to help increase yield. Over the course of 279 on-farm trials conducted between 2007 and 2014, the average yield increase to foliar fungicide application was 2.6 bu/acre. However fungicides are preventative. Even fungicides that are labeled as curative are unable to recover yield that has already been lost due to diseases damaging your crop. It is important to scout fields to catch any disease early on so we can help you decide the best fungicide application program that is specific to your field.

In warm humid conditions like we have had this year, white mold can be a common disease in our soybean fields. White mold is another disease that requires precise timing for fungicide control. Several foliar fungicides can be effective against white mold as well as other diseases when sufficient quantities of fungicides are applied to lower canopies. In white mold alone, research has shown a positive increase of up to 7 bu/acre when fungicides are applied in correct conditions.

While applying fungicides to soybeans is a new trend in the industry the benefits seem to make a positive impact in yields. Talk to any WS Ag Center consultant to further discuss a fungicide program that will work best for your soybean crop.

-Tom Arndt

I think most of us would agree that our crop is off to an excellent start so far!  The phrase, “Knee High by the Fourth of July” really doesn’t apply this year. With the potential for such a positive crop, I wanted to make a few comments on fungicide and plant health. There are four major benefits to plants from the application of a fungicide.

• The obvious one is broad spectrum disease control
• The remaining three include: preserves green leaf area, increased water use efficiency, and improved photosynthesis

Additional benefits include reduction of lodging due to healthier stalks and harvest ease, all leading to increased bushels in the bin.

Soybeans: We like to target R3 (beginning pod development) for key application timing in soybeans, which for our area occurs around mid-July. The    primary reason for this timing is to protect R4 pod fill which is the most critical time for soybean yield. Stress at this time cannot be recovered and results in more yield loss than at any other time.

Corn: Timing in corn starts at R1 (silking) to brown silk. WS provides application as we have again partnered with a professional aerial application service.  Now is a great time to place orders for fields to be covered as we are starting the planning/scheduling process for our aerial applicators.

A new product to consider in corn and soybean fungicide applications is Trivapro from Syngenta. “Tri” vapro is three fungicides in one, delivering the full six ounces of Quadris, the full four ounces of Tilt, and the full four ounces of Solotenol. These three different active ingredients providing up to 42 days of residual control. Trivapro is the longest lasting, hardest working fungicide on the market.

Please contact us at WS AG for further information on increasing yields with Trivapro.

-Marty Liegel

Syngenta

It seems that there are always debates or discussions about various topics in the world of soil fertility and fertilizer use. Some get resolved; others don’t. The comparative advantages and disadvantages of ortho- and poly-phosphate fertilizers has been an active topic for discussion since at least the early 1970s. It seems that the activity of this discussion has not diminished.  It appears that various marketing efforts have focused on the sale of either orthophosphates or polyphosphates. If we have some understanding of the chemistry of the soil and the manufacturing processes for these fertilizers, it will be possible to make informed choices about the use of these forms of phosphorus in crop production.

Manufacture of all inorganic phosphorus fertilizers begins with the mining of rock phosphate, a finite resource. This material is inert and the phosphorus present in the rock is insoluble, and thus, not available for use by plants. This rock is treated with sulfuric acid, and phosphoric acid is the important end product. Phosphoric acid is also produced by what is known as an electric arc process. This phosphoric acid is the start of the manufacturing of phosphate fertilizers.  Depending on the manufacturing process used, the phosphoric acid has phosphorus present in the form of orthophosphate or polyphosphate or a combination of both. In general, heat is added to orthophosphoric acid, water is removed, and acid with phosphorus present in the polyphosphate form is the end result. This acid is frequently referred to as “super acid”. Approximately 60% of the phosphorus is present as polyphosphate with the remaining 40% present as orthophosphate. To make 10-34-0, ammonia (NH3) is added to the “super acid” and most of the acid is neutralized. Thus, 60% of the phosphorus in 10-34-0 is in the polyphosphate form.

In another manufacturing process, urea (46-0-0) and potassium hydroxide (KOH) are added to the orthophosphoric acid to produce products like 9-18-9 or 6-24-6. The acid is neutralized by the addition of these two materials. The phosphorus in these and/or related products is present in the orthophosphate form. Because of the addition of 46-0-0 and KOH, these materials are usually more expensive. For the manufacture of dry phosphate fertilizers, NH3 is added to the orthophosphoric acid to produce either diammonium phosphate (18-46-0) or monoammonium phosphate (11-52-0). Different amounts of NH3 are used to produce the different products. Thus, phosphate in dry fertilizers is present in the orthophosphate form. Considering the differences in the manufacturing processes and properties of the end products produced, it’s reasonable to ask if there are any differences in the effectiveness of orthophosphate and polyphosphate fertilizers.

To answer this question, we can start by looking at some of the basic fundamentals. First, we know that phosphorus is aborbed or taken up by plants as either HPO4- in calcareous soils or  H2PO4- in acidic soils. These two ions can be thought of as phosphorus in the orthophosphate form. When water is removed to make the “super acid”, the orthophosphate ions combine. Any combination of two or more orthophosphate ions is called a polyphosphate. A polyphosphate is really a chain of various numbers of orthophosphate ions.

When added to soils, the polyphosphate unit combines with soil water, breaks down, and the orthophosphate units are the end result. This is a chemical reaction affected primarily by soil temperature and, in general, microorganisms are not involved. The speed of the conversion increases as soil temperature increases. Conversion is usually completed in 7 to 10 days-usually before corn germination and emergence. Based on our understanding of the chemistry of phosphorus in soils, we should expect no difference in the performance of orthophosphate and polyphosphate fertilizers.

-Dan Langkamp