Tag Archives: soil fertility

2020 Five County Agricultural Conference – King William, VA

The 2020 Five County Agricultural Conference will be held Wednesday, Jan. 15 at the King William Ruritan Club Building, 156 Ruritan Lane, King William, Virginia 23086. This year’s conference will include pesticide certification training, updates from FSA, NRCS, and SWCD, several Specialists and Agents from Virginia Cooperative Extension that will cover a wide variety of topics, and precision agriculture round-table discussion. In addition, you will be able to get your dicamba herbicide certification with training being offered by Don Cline of BASF. We look forward to seeing your there for a great day of learning and interaction with the experts. Lunch will be provided. Agenda detail are below.

Full Attendance to the conference has been approved for Private Pesticide Applicator Recertification in Category 90 and Commercial Categories 1A, 10, and 60.  The conference has also been approved for 1.5 Virginia Nutrient Management CEU, 2.5 Integrated Pest Management and 1.5 Crop Management CCA-CEU credits.

7:45 a.m.             Registration

8:15 a.m.             Grain Market Update, Robert Harper, Manager, Virginia Farm Bureau Grain Division

8:45 a.m.             Corn Update and Hybrid Selection – Dr. Wade Thomason

9:15 a.m.             Break

9:30 am.              Soybean basics and Soybean Variety Selection- Dr. David Holshouser, Extension Soybean Agronomist

10:00 a.m.           Crop Fertility and Fertilizers – Dr. Hunter Frame

10:30 a.m.           Precision Ag Discussion

11:45 a.m.            Cooperating Agencies (FSA, NRCS, and SWCD)

12:30 p.m.          Sponsored Lunch (Participants not seeking pesticide applicator recertification or Dicamba Certification are welcome

 to adjourn following lunch)

1:15 p.m.             Dicamba Certification – Don Cline, BASF Crop Protection

1:45 p.m.             Legal Update – Robert Christian, VDACS Pesticide Investigator

2:15 p.m.             Spill Response Activity – Robbie Longest/Mike Broaddus, Extension Agents, ANR, Essex and Caroline

3:00 p.m.             Wrap up paperwork and adjourn

Manganese Deficiencies in Soybean

Manganese (Mn) deficiencies are starting to appear.  Such a deficiency is common in Virginia soybean, but these deficiencies are not necessarily due to low Mn levels in the soil.  Instead, like many micronutrients (nutrients that are needed by the plant in small amounts), Mn availability to the soybean crop is directly related to soil pH.

When pH levels reach 6.5 or above, Mn deficiencies will likely appear, especially on sandy soils.  However, some soils with a pH of 6.2 and lower can show deficiencies if soil Mn is low.  Generally, Mn deficiencies are more common on our sandier soils as pH changes more rapidly and sandy soils typically have a lower Mn concentration.

The deficiency will appear interveinal clorosis, usually on the younger leaves first since Mn is not a mobile nutrient.  MnDeficiency0721101059This may distinguish Mn deficiency from magnesium (Mg) deficiency.  Magnesium deficiency symptoms will usually appear on the lower leaves while the upper leaves remain green.  Still, I’ve seen Mn deficiency on the lower to middle leaves.  This usually happens when the field has not been checked in a while and the observer missed the symptoms when they were on the younger leaves.Cyst nematode on roots

Other problems can cause look-alike symptoms similar to Mn deficiencies.  In particular, inter-veinal yellowing is a common symptom of soybean cyst or other nematode damage.  Therefore, it may be prudent to further investigate the problem, especially the root system.

 

Use the following guidelines for Mn applications:

Scout your fields.  Mn deficiencies may or may not materialize.  The only sure way to determine a deficiency is to observe the deficiency symptoms through visual observation or tissue tests.  The characteristic visual symptom is yellowing between the veins on the new leaves.  Mn is an immobile nutrient.  Therefore, it will not move out of older leaves to the new leaves.  Symptoms will appear when the plant can no longer extract sufficient amounts of the nutrient from the soil.

Take a tissue sample.  If Mn deficiencies are suspected due to high pH and/or a field history of Mn deficiencies, but no symptoms have yet appeared, you should consider taking a tissue sample.  Tissue samples can reveal deficiencies before symptoms appear (hidden hunger).  We suggest a tissue test if lime, lime stabilized biosolids, or an ash product was recently applied.

Manganese application.  To overcome a deficiency, apply ¾ lb. chelated Mn (elemental basis) or 1 lb. inorganic Mn (elemental basis) per acre to foliage upon appearance of symptoms and prior to flowering.  More than one application may be required to correct a severe deficiency.

Don’t use low rates to correct a deficiency.  Note that many Mn products recommend applying lower rates of Mn.  However, the label usually states that these are maintenance rates.  Once a deficiency occurs, these lower rates will not correct the deficiency and the rates stated above will be needed.

Split Mn application on deficiency-prone soils.  An alternate method of application can be used before a deficiency is evident on soils that commonly show a deficiency, especially on soils that have a high pH (above 6.8 or so).  A lower rate (~ ½ of that listed above) can be combined with another scheduled application, such as a postemergence herbicide or insecticide.  This may be a sufficient rate to prevent a deficiency from occurring.  But, continue to scout the field and take future corrective measures if visual deficiencies appear.  If a visual symptom appears, you need to use the full rate.  I will remind you that this is a preventative treatment.  A deficiency may not occur.  Furthermore, these are only maintenance rates and another application will likely be needed if the field is truly deficient.

Use EDTA chelated Mn formulations when mixing with glyphosate.  Be reminded that some Mn formulations in combination with glyphosate herbicide (Roundup, Touchdown, many generics, etc.) will result in reduced weed control of certain weeds.  Other herbicides have not shown to interact.  If including Mn with glyphosate, use the EDTA chelated formulation as it has shown not to interact.

Don’t spray if you don’t need it.  Mn can be toxic to soybean.  Spraying greater than recommended rates or spraying as a preventative spray when soil pH is relatively low (5.7-5.9) could lead to toxicity problems