Rootless Corn, Soybeans in June  06/07/17 4:14:11 PM

NEXT TUESDAY--Mynard Plot Tour  We have the tours RAIN OR SHINE—If raining--we will gather in our seed building—If the sun is shining--at our plot on the West side of Mynard Nebraska—1 mile South of our plant—1/4 west on Mynard Road OR 1-1/4 mile West of HWY 75 on Mynard Road—South Side of the Road.   The tours will last no longer than 1.5 hours and address any current agronomic issues as well as allow the attendees to monitor developmental progress of Asgrow and DeKalb genetics throughout the growing season.  View the current genetic lineup as well as population trials, planting speed trials, fungicide and insecticide seed treatment comparisons, biological seed treatments, the affects of starter fertilizers and more!   

2017 WBI Summer Dates

Date                            Location                      Time                            Guest Speakers/Topic

Tuesday June 13th       Mynard Plot                9-10:30 a.m.                Brady Kappler—BASF Tech Rep, Mark Thornburg—Monsanto          

                                                                                                            Post-emergence Soybean Weed Control Options—RR2Xtend

                                                                                                            Recommendations, Tank Mixes, Etc.

            So, as we approach the post-emergence soybean herbicide applications, a topic that has been developing for the past 10 years or so is the RR2Xtend Soybeans.  A fair amount of them have been planted and it seems timely that a review of the products available for application and their subsequent label requirements/changes seems appropriate.  We will also talk about tank mixes for RR2 Soybeans, recipes for problem weeds etc. 

 

Tuesday June 27th       Mynard Plot                9-10:30 a.m.               

Tuesday July 11th        Mynard Plot                9-10:30 a.m.

Tuesday July 25th        Mynard Plot                9-10:30 a.m.

August 2nd-6th              Springfield                                                      Sarpy Co. Fair

Tuesday August 8th     Mynard Plot                9-10:30 a.m.

August 9th-12th            Cass Co. Fairgrounds                                      Cass Co. Fair

Tuesday August 22nd  Mynard Plot                9-10:30 a.m.                Corn Breeder/Corn Lineup

                                                                                                            Soybean Breeder/Soybean Lineup

Tuesday August 29th   Cass Co. Fairgrounds                                      Late Summer Clinic

 

BRING A FRIEND AND WE WILL SEE YOU NEXT TUESDAY!!

 

Observations from the field this week—Here are a few things I have noticed with an explanation of why these have occurred—maybe you have seen this as well.

Purple Corn--When scouting your corn fields this spring, as always, it is important to correctly identify problem areas whether it be nutritional, chemical, environmental, etc.  SOME areas of SE Nebraska have/are experiencing corn plants with purple leaves.  The warm weather this week is starting to bring the plants out of this condition.   Genetic and environmental factors, as well as a deficiency in phosphorous, can cause the corn plant to turn purple.  Residue distribution from last year’s record harvest may also be a factor here due to seed/soil contact and fertility tie-up.

 

Corn plants often develop a purple tint in their leaves because of stress and limited root development. More specifically, plants respond to stress by producing large amounts of anthocyanin  which causes the leaf to turn purple.  (When chlorophyll disappears from a leaf, the remaining carotene causes the leaf to appear yellow. A third pigment, or class of pigments, that occur in leaves are the anthocyanins. Anthocyanins absorb blue, blue-green, and green light. causing the corn leaves to turn a shade of purple)

 

Causes of Purple Corn--A variety of conditions are known to cause corn plants to develop a purple tint in their leaves:

 

¨ Phosphorous deficiencies

¨ Cold temperatures

¨ Wet soils

¨ Compaction

¨ Root injury.

 

Have we had all of these conditions this spring?  YES!!

 

Some corn genetics will naturally express more purpling than others.  It is s talking point of how purple the corn is upon emergence, but, normally does not impact the yield of the hybrid much in the end, unless aggravated by additional factors throughout the season.

Environmental stresses that restrict the plant’s sugar production can cause a purple tint in the leaves. Also, plants suffering from phosphorous deficiencies grow slowly, stalks are thin and shortened, maturity is usually delayed, and lower leaf tips have a purple appearance.

 

Does this mean anything?  Normally, NO.  If the purple coloring on the leaves is caused by root restrictions from cool temperatures, is usually only temporary,and the plant should recover. If the root system recovers from injury, the plant should turn green again now that warmer temperatures have returned. Yields should not be impacted from this condition. You should dig up a few plants to ensure that cooler temperatures and wet soils of the spring are the problem. You may discover the root injury is from insects, diseases, or soil compaction.  This might impact your yields if dry conditions develop this summer.   If your soil is has Phosphorus deficiencies, which can limit root development, this may restrict vegetative growth and grain development.

 

Sources:

Elmore, R., and Abendroth, L. Why Are Corn Seedlings Turning Purple. Integrated Crop Management. Iowa State

University Extension. IC-496 (10).

Thomison, P. and Mullen, R. Purple Corn, What is Going On? C.O.R.N. Newsletter. Ohio State University Extension.

May 11-18, 2004.

 

THE ROOT OF THE PROBLEM

Causes of Rootless Corn Syndrome--Rootless corn syndrome occurs in young corn plants when there is limited or no nodal root development. One of the primary causes is furrow or sidewall compaction, especially in conventional tillage or heavy mucky soils.  This can be amplified if hot and dry soil conditions during early root development (V2 to V4), and by shallow planting depths, compacted soils, and loose or cloddy soil conditions. Additionally, it is seen when the seed furrow opens up after planting, generally in dry conditions.  Now where I have noticed this spring is in areas that have had heavy traffic (gateways) and/or parts of the fields that likely were too wet to be planted when planting occurred.  This was generally un-avoidable to some degree, in many situations this spring when there was no “perfect” day or conditions to plant much of anything. 

 

Under normal soil conditions, nodal roots begin developing at the growing point (crown) located where the top of the mesocotyl and base of the coleoptiles meet. If corn seed is planted at least 1½ to 2 inches deep, then the nodal (or crown) roots begin developing at

about ¾ inches below the soil surface. However, in rootless corn scenarios, the nodal roots may have stopped developing because upper soil conditions were too dry. Young roots that emerge from the crown area of the plant will die if their root tips dry out prior to successful root establishment in moist soil.

Symptoms of Rootless Corn Syndrome--Plants exhibiting rootless corn symptoms can occur around V6 to V8, or, once the plant achieves substantial vegetative growth—prior to tassel (VT) have either lodged and are laying on the ground. Before symptoms appear, corn plants may appear vigorous and healthy, but after strong winds or thunderstorms, plants can fall over due to limited or no root support. Affected plants lack all or most nodal roots; existing nodal roots may appear stubby, blunt, and not anchored to the soil.

 

Effect on Corn Plants The nodal roots are important in providing the majority of water and nutrients that the corn plant needs for normal growth and development. Therefore, due to a lack of root mass, the rootless plants may wilt or eventually pre-maturely die in extreme conditions (dry).  Now if timely rainfall occurs, you will not likely notice any long-term effects of any of this. Plants are

forced to rely on the seed root system or limited nodal root growth until more favorable temperatures and moisture conditions allow nodal root growth to resume. However, adequate rainfall will promote crown root development and many plants can recover after lodging. Recovery is severely hampered if conditions are dry.

 

Late Planting of Soybeans Due to the excessive rains this spring has some farmers are still planting soybeans.  It may be the first or second time.  But this is a timely reminder of a couple of considerations, if in fact you still have some soybeans to plant.   Late planting of soybeans requires a few more management considerations, such as soybean maturity, row spacing, planting rates, weed control, etc..

Soybean Maturity

Growers are now at the point where where soybean maturity should be changed in order to allow for complete maturity of the plant this fall. Switching to mid– to full-season adapted products are recommended. WHAT?  This is true, I fuller season been (within 0.5-1.0 of your normal maturity range) is preferred, because a soybean earlier maturity will not achieve adequate height for setting pods. Late-planted soybeans go through growth stages much faster than early planted soybeans. The reason is that in addition to temperature, soybean development is influenced by day length. Thus, soybeans planted later do not develop the same canopy biomass as soybeans of the same variety planted earlier.

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Row Spacing--Narrow rows or drilling (if not already done) should be used with late plantings to increase sunlight interception and increase biomass accumulation.

Planting Rates--Planting rates should increase 10 to 15%, due in part to smaller plants with later planting.  We want the plants to compete with each other to achieve a faster plant height to increase node count, flower count, and pod count.  A thicker stand can achieve just that.

Weed Control--Weed management is a priority for late-planted soybeans due to lack of canopy to compete with weeds. Row spacing should also be less than 30 inches to hasten canopy closure.

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In summary, late planting can have a significant effect on soybean yield potential. Previous research from Iowa State University and Purdue University indicates we can expect 60 to 80% of the maximum yield when planting is done around June 15 to 20.  As you approach June 30 without the soybean crop being planted, yield potential decreases to 45 to 70% of the maximum yield.

 

John W. McNamara

Agronomist

Wiles Bros. Inc.

606 Wiles Road

Plattsmouth NE. 68048

(402) 298-8550--Office

(402) 499-3870--Cell

(402) 298-7174--Fax

 
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