Fertility

Why are my soybeans yellow? Part 4

Soybeans throughout the county are beginning to look better.  Development has been slowed and many fields have areas (sometimes large areas) with a light green or yellowish tint to the beans.  What is causing this yellowing? One possibility is:

Nutrient Deficiencies

NITROGEN DEFICIENCY

Caused many fields to turn yellow in late June and July.  A dry spring delayed nodulation, then heavy rainfall saturated soils just as plants required large amount of N during the rapid growth phase. There is often a lag phase when nodulation and N fixation is insufficient to supply enough N for the plants demands early in the season.
The good news is that most fields will recover as soils dry out and biological nitrogen fixation catches up to demand.
Some farmers have asked if N fertilizer could be added to these fields to help them through this yellow phase.  Although applying N fertilizer does help green up the plants there is no economic benefit.  Numerous trials conducted in Ontario, Canada  show the average yield response to N fertilization is less than two bushels per acre.

Reposted from Tim Barnes, OSU Extension Marion County July 16,2023

POTASSIUM DEFICIENCY

Potassium (K) deficiency symptoms are frequently seen on soybean at early development stages (starting as early as V3) but can also develop on plants throughout the growing season. Potassium deficiency symptoms include yellowing of leaf tissue starting at the leaf tip and moving down the leaf margin (outer edge of leaf) (Figure 1). Severe K deficiency can lead to pre-mature leaf fall of the older leaves.

Potassium deficiency symptoms are often more severe in years where root growth is slowed or delayed (wet or dry years) and can be observed in fields with adequate soil test K levels.  A poorly developed root system can limit nutrient uptake causing what is likely a temporary nutrient deficiency.   These deficiency symptoms often decrease or disappear once adequate root development and soil conditions improve.

IRON DEFICIENCY CHLOROSIS

Iron deficiency chlorosis (IDC) is most common in poorly drained areas of the field. Plants with IDC tend to be stunted and yellowing occurs between the leaf veins while veins remain green (interveinal chlorosis). Leaves may also develop brown and necrotic spots in leaf margins. Iron is an immobile nutrient, so these symptoms most often occur first on newer, upper leaves.

IDC  symptoms are more common in years where root growth is slowed or delayed (wet or dry years).  A poorly developed root system can limit nutrient uptake causing what is likely a temporary deficiency symptomology.   These deficiency symptoms often decrease or disappear once adequate root development and soil conditions improve.

 

Why are my soybeans yellow? Part 3

Soybeans throughout the county are beginning to look better.  Development has been slowed and many fields have areas (sometimes large areas) with a light green or yellowish tint to the beans.  What is causing this yellowing? One possibility is:

Too much water/waterlogged roots

In some fields, the pale green to yellow leaves are the result of very wet soil conditions. Soybeans are a legume (like alfalfa) and do not like wet feet (roots)! This problem is commonly seen in low areas of the field or on poorly drained soils where water tends to stay for a prolonged period of time. When digging up plants in wet areas of the field you will find poorly developed or weaker root systems when compared to a healthy plant.

Soil water content is critical not only to supply the water needs of the plant, but to also dissolve nutrients and make them available to the plant. A poorly developed root system can limit nutrient uptake causing what is likely a temporary nutrient deficiency.

Temporary nutrient deficiencies can be observed when excess water in the soil depletes oxygen and builds up carbon dioxide levels. Although oxygen is needed by roots to grow and take up nutrients, high carbon dioxide levels are toxic and limit root growth and activity.

With better weather conditions plants will usually (sometimes slowly) grow through this phase.

Soybean nutrient deficiencies will be discussed in a different post.

Consideration for Corn N Management under Dry Soil Conditions

Source: C.O.R.N. Newsletter

Sidedress applications of nitrogen have begun and many more fields will receive applications in the upcoming week.  The information below from the C.O.R.N. Newsletter maybe of some interest.

When considering adjusting your corn nitrogen program for dry weather conditions, consider how N gets to the root system for uptake. Mass flow is the primary mechanism for nitrogen (also sulfur, magnesium, and calcium). Mass flow is where nutrients in soil solution move toward the root as the plant takes up and transpires water through the crop canopy. Also, consider how dry weather affects the plant root system. Root growth will slow in dry soils, the situation we are now experiencing in the upper soil depths. Fortunately, root growth will re-establish, and the mass flow of nitrogen will quickly improve with rainfall. Here are a few considerations for managing N applications.

Nitrogen placement is one area to consider changes within the limitation of equipment available. The nodal root system originating from the lowermost nodes will take up nearly all N. Normally we discourage surface applications of nitrogen due to potential volatilization losses of N in urea form found in UAN or urea. Under dry weather conditions, we have limited opportunities for rainfall to move N into position for uptake. The goal should be to have nitrogen close to the root system and close to roots actively taking up water. So, moving UAN placement closer to the row and a little deeper will improve plant access. Anhydrous application is already deep enough and moving closer to the row increases root injury potential, so no adjustment is needed.

Nitrogen rate is another consideration. Looking at our N yield response data from 1998-2022 does not show that lower yields usually require less fertilizer N than higher yields. We think that’s because the causes of lower yields, which are typically stress from having less available water at critical times, often affect root growth, and so may make it harder for plants to take up the N that is in the soil. If your plan was to apply a rate based on the Corn Nitrogen Rate Calculator (https://www.cornnratecalc.org) which is for corn after soybean and a N:Corn Price between 0.1 and 0.15, the rate is 160 to 181 pounds of N per acre then stay with that amount. If the plan was to apply more than that, then cutting back would be reasonable.

A final consideration is timing. Application systems that make late-season applications possible have become more common. Putting down a reasonable side-dress rate and then basing a later application on rainfall could be a reasonable strategy.

Cover crops would also be something to start looking at now. We know if the yield falls short of normal, we will have excess soil nitrogen left after the growing season. The edge of field studies conducted by USDA-ARS has shown we can recover a substantial amount of this residual N through a cover crop. Exploring available cost-share programs with NRCS and SWCD would be a reasonable way to retain that valuable N on your field for a future crop.

When and How Much Nitrogen to Apply to Wheat

Wheat has already reached green-up across the state so spring N may be applied anytime fields are fit. Keep in mind that research has shown no yield benefit to early N applications as long as the application was made by Feekes – 6 (one visible node).  If you need a reminder on how to assess if wheat is at Feekes GS 6, see this video: https://www.youtube.com/watch?v=D_f3VrqzV5c.  Nitrogen applied early has the potential to be lost since wheat will use little N until after jointing. Urea-ammonium nitrate (UAN) or 28% has the greatest potential for loss and ammonium sulfate the least. Urea will have little potential for loss as long as it does not volatize. No stabilizer will protect the nitrate component of UAN, which is roughly 25% of the total N in UAN at application time.

Ohio State University recommends the Tri-State Fertilizer Recommendation Bulletin for N rates in wheat. This system relies on yield potential. As a producer, you can increase or reduce your N rate by changing the value for yield potential. Thus, a realistic yield potential is needed to determine the optimum N rate.  To select a realistic yield potential, look at wheat yield from the past five years.  Throw out the highest and lowest wheat yield, and average the remaining three wheat yields.  This three-year average should reflect the realistic yield potential.

Table 10 in the Tri-State Fertilizer Bulletin recommends 120 lb N for yield goals of 100 bu/A, 110 for 90 bu/A crop, 90 lb for 80 bu/A crop, and  80 lb for a 70 bu/A crops. These recommendations are for total N. If you prefer to be more specific, the following equation may be used for mineral soils, which have both 1 to 5% organic matter and adequate drainage:

N Rate = (1.33 x Yield potential) – 13.

No credit is given for previous soybean or cover crops, since it is not known if that organic N source will be released soon enough for the wheat crop. The Tri-State Fertilizers Bulletin recommends that you subtract from the total (spring N) any fall applied N. I would take no more than a 20 lb/A credit even if you applied a larger amount. Whether you deduct fall N depends how much risk you are willing to take and your anticipated return of investment from additional N. Based on the equation above and deducting 20 lb from a fall application, a spring application of 100 lb N per acre would be recommended for a yield potential of 100 bu, 90 for 90 bu potential; and 70 for a 80 bu potential.  Nitrogen rate studies at the Northwest Agricultural Research Station over the past 20 years have shown the optimum rate varies depending on the year. However, averaged over years, yield data from these studies correspond well with the recommendation equation given above. These studies have also shown apart from one year, yields did not increase above a spring rate of 120 lb N per acre.

Wheat generally does not benefit from a nitrification inhibitor since temperatures are relatively cool at application time and the application is made to a growing crop, this is especially true as the crop approaches Feekes – 6. However urea may benefit from a urease inhibitor (products containing NBPT) if conditions for volatilization exist for several days after application. These conditions would include an extended dry period with warm drying temperatures (risk increases with temperatures above 70°F) and evaporating winds. Urea applications need at least a half inch rain within 48 hours to minimize volatilization losses unless temperatures remain relatively cool. The urease inhibitor will prevent volatilization for 10 to 14 days with the anticipation of a significant rainfall event during this time.

ESN or polymer coated urea will reduce the potential for N loss from leaching, denitrification, and volatilization. Since these conditions are unlikely to occur in most years, it may not be economical to use this product. Cool weather may prevent the timely release of N from ESN, so if ESN is applied, it should be mixed with urea or ammonium sulfate and be no more than 60% ESN.

A split application of N may be used to spread the risk of N loss and to improve N use efficiency. However, Ohio State University research has not shown a yield increase from this practice compared to a single application after green-up. In a split system, the first application should be applied no sooner than green-up. A smaller rate should be applied with the first application since little is needed by the crop at that time and the larger rate applied closer to Feekes – 6.

Wheat Growth Stages

OK, Mother Nature is not cooperating which means we can’t talk about corn and bean planting so let’s talk about the crop we do have growing – Wheat

Source: K-State University

Knowing what growth stage your wheat crop is at is essential for nitrogen, herbicide and possibly fungicide applications.  Most of the wheat I have seen in the county so far is between Feekes 5 and Feekes 6.

Feekes 5 is the time to be making your last nitrogen applications and applying herbicides as needed for weed control.  However at Feekes 6 you should cutoff for nitrogen applications to avoid leaf injury.  Additionally some growth regulator herbicides, like 2, 4-D and dicamba should not be applied.

REMINDER: Join Us for the 2nd Annual Virtual Corn College and Soybean School

By: Laura Lindsey

The AgCrops Team will host the 2nd annual virtual Corn College and Soybean School on February 15, 2022 from 9:00 AM – 4:00 PM featuring your OSU Extension state specialists, including the new corn agronomist, Dr. Osler Ortez, and new soybean pathologist, Dr. Horacio Lopez-Nicora. CCA CEUs will be available during the live presentations (2.0 CM, 5.0 IPM, and 1.0 NM).

To register, please go to: http://go.osu.edu/cornsoy There is a $10 registration fee for this event, which goes directly to support OSU AgCrops Team activities. Presentations will be recorded and uploaded to the AgCrops Team YouTube channel after the event (https://www.youtube.com/c/OSUAgronomicCrops).

MORNING SESSION 9:00-noon

9:00-9:40              Laura Lindsey

Soybean Management for 2022

9:50-10:30           Osler Ortez

Corn Management for 2022

10:40-11:20         Horacio Lopez-Nicora

Soybean Disease Management

11:20-noon         Pierce Paul

Corn Disease Management

AFTERNOON SESSION 1:00-4:00

1:00-1:40              Kelley Tilmon

Soybean Insect Management

1:50-2:30              Andy Michel

Corn Insect Management

2:40-3:20              Mark Loux

Weed Management for Corn and Soybean

3:20-4:00              Steve Culman

Meeting Nutrient Needs for Corn and Soybean

Yep … The Problem is Agriculture!!??

Source: OFBF (edited)

Yeah it’s easier, let’s just blame agriculture!

Why are they allowed to put ANY sewage in the river? 

Where have the regulators been for the last 20 years?

A fine of only $29,936.00 which equals about $.00001 per gallon

Given 30 years to fix the problem – WHAT????

Maybe now we have found the real problem! 

 

Unlike permitted livestock farms, such as CAFOs, that are not allowed to discharge an ounce of manure into Ohio’s waterways, municipalities have agreements with Ohio EPA to allow for a certain amount of sewage to be dumped directly into tributaries located in watersheds that flow into Lake Erie.

For Maumee, Ohio, that agreement is 25 million gallons per year. However, due to an outdated sewer infrastructure, the municipality has actually been adding as much as 150 million gallons of sewage into the Maumee River for each of the past 20 years.

City Law Director David Busick confirmed that Department of Public Service Sewer Division employees, who keep track of sewer discharge levels, did not comply with the law when they failed to self-report the incidences of annual sewer overflow in Maumee. The City Council has since approved an action plan that requires mandated maintenance upgrades and infrastructure replacement guidelines. The city has also been fined by Ohio EPA to the tune of $29,936. which can be applied to remediation steps.

“We have always said that water quality issues are complex, involving many sources of nutrients, changing weather patterns and lack of data,” said Adam Sharp, executive vice president of Ohio Farm Bureau. “We are certainly not absolving agriculture of its contribution to this challenge or responsibility in finding solutions, but what Maumee has been doing over the past two decades is disturbing and makes you wonder if other municipalities with equally run down sewer infrastructures are having similar issues.”

During the same period that Maumee was illegally dumping massive amounts of sewage, Ohio farmers have been using new equipment and technology to maximize the placement of nutrients used for crop production. They also are following strict state regulations and participating in voluntary water quality programs like H2Ohio find better management practices to minimize the amount of nutrient runoff from farm fields and into the watershed.

“Farmers have been heavily scrutinized for their impact on Lake Erie and have answered that criticism with unprecedented efforts to help solve the problem. It is time to hold municipal administrations and their wastewater facilities to the same standards,” Sharp said. “If a city’s wastewater infrastructure is failing, those issues should be addressed immediately with the same urgent action Ohio agriculture has taken to protect Ohio’s water quality.”

 

Nutrient Removal for Field Crops in Ohio

Source: Harold Watters, OSU Extension

An update for nutrient recommendations for Ohio’s major field crops (corn, soybean, wheat, and alfalfa) was published in 2020 as the Tri-State Fertilizer Recommendations for Corn, Soybean, Wheat, and Alfalfa. This fact sheet builds on that information, and expands it to include recommendations for other agronomic crops grown in Ohio.

*from one state value.
1 Tri-State Fertilizer Recommendations for Corn, Soybean, Wheat, and Alfalfa
2 Forages/hay is presented as 10% moisture content except where noted.

Click here to view the entire factsheet

 

Fine-tuning Fertilizer

Quantifying soil spatial variability doesn’t do a farmer any good unless they are able to respond to that variability. Dr. John Fulton, Professor in the Department of Food, Agricultural and Biological Engineering at The Ohio State University, joins the FarmBits Podcast to discuss variable rate application technology and effective input management methods for responding to spatial variability.

Is It Too Early to Apply Nitrogen to Wheat?—-Yes

Source: Laura Lindsey, Ed Lentz, OSU Extension

With melted snow and warmer weather in the forecast, is it time to apply nitrogen to wheat?

The short answer. Wait until green-up to apply N to wheat.

The long answer. Wheat does not require large amounts of N until stem elongation/jointing (Feekes Growth Stage 6), which is generally the middle or the end of April depending on the location in the state and spring temperature. Ohio research has shown no yield benefit from N applications made prior to this time. Soil organic matter and/or N applied at planting generally provide sufficient N for early growth until stem elongation.

Nitrogen applied prior to rapid uptake by the plant has the potential to be lost and unavailable for the crop. Nitrogen source will also affect the potential for loss. Urea-ammonium nitrate (28%) has the greatest potential for loss, ammonium sulfate the least, and urea would be somewhere between the two other sources.

Ohio research has shown that yield losses may occur from N applied prior to green-up regardless of the N source. The level of loss depends on the year (losses are smaller if the ground is not frozen or snow/ice covered). This same research did not observe a yield increase from applications made prior to green-up compared to green-up or Feekes Growth Stage 6 applications. Keep in mind that green-up is a descriptive, relative term and not a definable growth stage. Our definition of green-up is when the new growth of spring has covered the dead tissue from winter giving the field a solid green color- thus, growing plants.

There is a legitimate concern that wet weather may prevent application of N at early stem elongation. Ohio research has shown a yield decrease may occur when N application is delayed until Feekes Growth Stage 9 (flag leaf fully emerged). Thus, a practical comprise is to topdress N at any time fields are suitable for application after initial green-up to early stem elongation. There is still a potential for loss even at green-up applications. To lessen this risk a producer may want to use a N source that has a lower potential for loss such as urea or ammonium sulfate. ESN (polymer-coated urea) is another option but it needs to be blended with urea or ammonium sulfate to ensure enough N will be available for the crop between Feekes Growth Stage 6-9. The source of N becomes less important as the application date approaches stem elongation. The percentage of urea and/or ammonium sulfate would need to be increased with ESN for application times closer to Feekes Growth Stage 6. A producer may want to consider the use of a urease inhibitor with urea if conditions are favorable for volatilization losses: warming temperatures, drying winds and no rain in the forecast for 48 hours.

A split application of N may also be used to spread the risk of N loss and to improve N efficiency; however, Ohio State University research has not shown a yield increase from this practice compared to a single application after green-up. In a split system, the first application should be applied no sooner than green-up. A small rate should be applied with the first application since little is needed by the crop at that time and the larger rate applied closer to Feekes Growth Stage 6.

In summary, a producer may get away with applying N prior to green-up on wheat. However, university data has not shown a yield advantage for these early applications, but results have shown in certain years a major N loss and yield reduction from applications prior to green-up. Why take the risk? Just wait until green-up; the wheat does not need most of the N until April and May anyway.