Weather

We Now Turn Our Attention to Autumn Harvest Season

Source: Jim Noel

The cooler than normal blob of water in the eastern Pacific Ocean near the equator tends to push the first autumn freeze later than normal in our region. Therefore, there is no indication of an early freeze in September this year. It appears the first freeze for Ohio will not come until October either on schedule or a bit later than normal.

September looks to have the first half start cooler than normal followed by a return to normal temperatures for second half of the month.  Precipitation will be normal or sightly above normal for September. Normal rainfall is currently 1-1.5 inches per two weeks dropping to about an inch per two weeks for the second half of September. Even though we expect rainfall at or slightly above normal in September, there is a great deal of uncertainty due to the tropics and where those systems will travel. So you will want to pay attention to later outlooks at: https://www.cpc.ncep.noaa.gov

Rainfall for the first half of September will average 0.50-2.00 inches. The heaviest rains will likely surround the state of Ohio in most directions.

October into part of November looks to resume the above normal temperatures which should create an extended autumn this year. Rainfall remains highly uncertain but it appears near normal is the most likely outcome for October and November as we have some climate models showing above normal and some below normal rainfall.

The early outlook for winter calls for above normal temperatures first half and below normal temperatures second half. Precipitation is likely to become above normal with potential influences from the tropical Pacific Ocean.

 

Potential for Nitrate Problems in Drought Stressed Corn

Source: Peter Thomison, Laura Lindsey, OSU

Have very dry soil conditions increase the potential for toxic levels of nitrates in corn harvested for silage? Nitrates absorbed from the soil by plant roots are normally incorporated into plant tissue as amino acids, proteins, and other nitrogenous compounds. Thus, the concentration of nitrate in the plant is usually low. The primary site for converting nitrates to these products is in the growing leaves. Under unfavorable growing conditions, especially drought, this conversion process is slowed, causing nitrate to accumulate in the stalks, stems, and other conductive tissue. The highest concentration of nitrates is in the lower part of the stalk or stem. For example, the bulk of the nitrate in a drought-stricken corn plant can be found in the bottom third of the stalk. If moisture conditions improve, the conversion process accelerates and within a few days, nitrate levels in the plant return to normal.

The highest levels of nitrate accumulate when drought occurs after a period of heavy nitrate uptake by the corn plant. Heavy nitrate uptake begins at the V6 growth stage and continues through the silking stage. Therefore, a drought during or immediately after pollination is often associated with the highest accumulation of nitrates. Extended drought prior to pollination is not necessarily a prelude to high accumulations of nitrate. The resumption of normal plant growth from heavy rainfall will reduce nitrate accumulation in corn plants, and harvest should be delayed for at least 1 to 2 weeks after the rainfall. Not all drought conditions cause high nitrate levels in plant. If the soil nitrate supply is low in the dry soil surface, plant roots will not absorb nitrates. Some soil moisture is necessary for absorption and accumulation of the nitrates.

If growers want to salvage part of their drought damaged corn crop as silage, it’s best to delay harvest to maximize grain filling, if ears have formed. Even though leaves may be dying, the stalk and ear often have enough extra water for good keep. Kernels will continue to fill and the increases in dry matter will more than compensate for leaf loss unless plants are actually dying or dead. Moreover, if nitrate levels are high or questionable, they will decrease as the plant gets older and nitrates are converted to proteins in the ear.

Iowa Farmers Face Harvest Challenge

Source: Todd Neeley, DTN

The derecho fizzled out before it reached us!  I remember the one several years ago, the damage can be amazing.  Iowa farmers were hit hard by a derecho this year.

 

OMAHA (DTN) — One thing has become clear as crop experts tour the damage left behind by the derecho that ripped through Iowa this week: Farmers will face a multitude of challenges come harvest.

Trevor Birchmier, a farmer and owner of Central Iowa Shortline of Maxwell, a farm store and equipment business, told DTN that about 2,400 acres of corn went down on his farm in addition to three 42-foot bins holding 40,000 bushels each.

In all, he lost a total of between 150,000 to 175,000 bushels storage.

Prior to the storm, his crop was doing well.

“We were looking incredible,” Birchmier said. “Barely got rain, but when it came, it was at the right time. Such a good spring and early part of the growing season. It got a great start. Our corn looked tremendous. We were looking forward to a heck of a bumper crop, probably one of our best.”

So far, Birchmier has bagged between 100,000 and 150,000 bushels, with hopes his bins can be repaired before harvest.

“We called our contractor,” he said. “He assured us we will have bins by harvest on concrete pads that are there. It seems far-fetched, but I hope it happens.”

For his customers, Birchmier said he ordered an extra 750,000 bushels of storage bags to help area producers.

Preliminary estimates place total damaged acres at around 10 million, with a wide variety of damage from field to field across central and eastern parts of Iowa.

That’s on top of millions of bushels of commercial and on-farm storage lost in winds topping 100 miles per hour in some areas of the state.

YIELD LOSS POTENTIAL

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Climate and Hydrology Pattern to Relax in August

Source: Jim Noel

The overall drier pattern in many but not all places in Ohio this summer appears like it will relax closer to normal in August. The greatest uncertainty with the outlook will center around how the tropical moisture impacts the eastern United States.

The August outlook for temperatures indicates 1-2F above normal but a lot closer to normal than what we have seen this summer with the heat. The last time we have seen this much hot weather was 2015 and 2012. The good news is the worst of the heat for 2020 appears over. What this means is we should see a lot more maximum temperatures in the 80s with some 90s thrown in. Expected minimum temperatures mostly in the 60s to lower 70s.

The August outlook for rainfall indicates somewhat improving conditions. There is uncertainty here due to tropical moisture and where it flows. Normal rainfall is in the 3-4 inch range and rainfall is expected to average in the 2-4 inches range with a few higher totals. This will put us a lot closer to normal wetness. The 2 inch totals are more likely in northern Ohio and the 4 inches totals are more likely in southern Ohio.

It appears that the scattered drought conditions in Ohio are likely peaking and some improvement is possible over the next several months.

The outlook for September to November for the end of growing season into harvest season suggests warmer than normal weather will persist and low chances for an early freeze. Rainfall is shaping up to not be too far from normal.

Mid-Season Weed Management in Soybeans – Hot, Dry Edition

Source: Mark Loux, OSU

A few weed-related observations while we try to stay cool and hope for a day of rain or at least popup thunderstorms.

 

  • One of the frequent questions during extended dry weather is – do I wait for rain before applying POST herbicides, or just go ahead and apply before the weeds get any larger and tougher to control.  Our experience has been that it’s best to go ahead and apply when weeds are still small, even if it’s dry, and herbicides will usually do what they are supposed to.  Letting them get larger without any sure forecast for rain can make for a tough situation that requires higher rates or a more injurious mix.  On the other hand, waiting to apply can be fine if there is a good chance of rain within the next few days.  It’s not always an easy decision.
  • The deadline for applying dicamba to Xtend soybeans was June 30.  Tavium can still be applied where the soybeans were planted less than 45 days ago and have not exceeded V4, an alternative to dicamba will have to be used.  We should point out that very hot days and warm nights are not appropriate conditions for applying dicamba anyway.
  • The replacement for dicamba on Xtend soybeans is usually going to be glyphosate or a mix of glyphosate with either fomesafen (Flexstar, etc), Cobra/Phoenix, or Ultra Blazer.  Will they cause soybean injury?  Yes.  Will the injury be worse under hot conditions?  Probably.  Do you want weed control?  We assume yes.  Using a less aggressive adjuvant approach can reduce the injury.  Example – applying fomesafen with MSO + AMS will be less injurious than COC + UAN.  Be sure to use adjuvants appropriate for the weed species and size though.
  • Applying POST herbicides early or late in the day may have some potential to reduce injury.  Keep in mind however that the activity of most POST herbicides on weeds is reduced during overnight hours.  In previous OSU research where we applied herbicides at 3-hour intervals from 6 am to 9 pm, activity was substantially reduced from 9 pm through 6 am.  So activity was decreasing after 6 pm and ramping back up after 6 am.  Our studies included fomesafen, glyphosate, Firstrate, 2,4-D, and glufosinate.  Of these herbicides, 2,4-D was the only one not affected by time of day.   Giant ragweed was the only broadleaf weed in the 2,4-D study, which occurred in wheat stubble.

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Corn Growth in Hot and Dry Conditions

Source: Alexander Lindsey, Peter Thomison, OSU

In recent days we have been experiencing 90 degree F days with limited precipitation, and so we are starting to see some leaf rolling in corn. Some of this may be related to reductions in soil moisture, but may be related to restricted root systems as well. Depending on the stage of corn at the time of these conditions, different effects on yield may be expected. Corn ear development occurs throughout the growing season, and extreme temperature or moisture stress at different growth stages will decrease different aspects of grain yield. Below is a quick summary of the yield component most affected by environmental stress at different growth stages:

  • V5-7: Number of kernel rows. Corn plants are determining the number of kernel rows as early as V5 in some corn hybrids. By V7, the number of kernel rows in the primary ear has been determined for most hybrids.
  • V9-VT: Number of potential kernels per row (row length). Each potential kernel comes from one floret on the ear (female flower), and as conditions are more favorable for development the plant will initiate more florets. The number of potential kernels on the ear can be set through late vegetative stages (through V16).
  • VT/R1: Number of potential kernels that are fertilized. High temperatures and moisture stress can cause pollen release to occur before silk emergence resulting in poor pollination, and can decrease pollen grain viability. Ear elongation is occurring during R1, and if stress occurs total ear length could be decreased. Yield losses have been estimated up to 13% per day of stress.
  • R2-R3: Kernel number to be filled. Stress at the blister (R2) and milk (R3) stage can cause fertilized kernels to be aborted due to poor carbohydrate availability. Carbohydrate production will decrease as temperature and moisture stress increase because photosynthesis is reduced. The limited production of sugars will cause the plant to abort kernels, typically those that were the last to be pollinated (at the tip).
  • R4-R5: Kernel size. At the dough (R4) and dent (R5) stages, carbohydrate accumulation within the kernels will be reduced due to environmental stress. At the start of R5, only 45% of the dry matter in each kernel has been accumulated, leaving half of the starch to be added during R5. However, the kernel contains 90% of its dry matter halfway through the R5 growth stage (milkline halfway down the kernel).

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What a Difference a Year Makes in the Weather

By: Aaron Wilson, OSU

Things change quickly when it comes to weather and climate. Recall 2019, a record wet start to the year for many across Ohio, only to see 26% of the state enveloped in moderate drought conditions by October. Though not nearly as wet as last year, it has been wetter than average through the first five months of 2020.

Figure 1: Multi-sensor observed month-to-date precipitation ending on June 22, 2020. Figure from the Midwestern Regional Climate Center (https://mrcc.illinois.edu).

Things change quickly when it comes to weather and climate. Recall 2019, a record wet start to the year for many across Ohio, only to see 26% of the state enveloped in moderate drought conditions by October. Though not nearly as wet as last year, it has been wetter than average through the first five months of 2020.

Since our calendar flipped to the meteorological summer on June 1, however, precipitation has all but turned off across western and northwest Ohio (Figure 1). Most areas here have seen an inch or less of rainfall. Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) observers in Ada, Napoleon, and Lima have only recorded 0.18”, 0.29”, and 0.40” of rainfall so far for the month! With warm summer conditions, this has led to intense evaporation rates and rapidly drying soils. To submit a report of drought impacts for your area, consider the Drought Impact Reporter. For more information on recent climate conditions and impacts, check out the latest Hydro-Climate Assessment from the State Climate Office of Ohio.

Figure 2: Forecast precipitation for the next 7 days. Valid from 8 pm Monday June 23, 2020 through 8 pm Monday June 30, 2020. Figure from the Weather Prediction Center https://www.wpc.ncep.noaa.gov/).

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Summer Climate and Grain Market Outlook Webinar

State Climatology Field Specialist, Aaron Wilson and Ben Brown, Assistant Professor of Professional Practice in Agricultural Risk Management, both with The Ohio State University will give a summer weather and grain market update after the release of the 2020 Acreage and Grain Stocks Reports. Due to the Coronavirus, economic conditions for corn changed rapidly after the March Prospective Plantings Report, with likely changes in acreage for the Eastern Corn-Belt. Weather, as always, during July and August will play a major factor in final yields and production in 2020. Free Registration can be found at go.osu.edu/2020agoutlook