Volume 12, Issue 4 - May 2022

David Moseley, Price, III, Paul P, Padgett, Guy B., Foster, Matthew, Parvej, Md Rasel, Morlin Carneiro, Franciele, Lopes de Brito Filho, Armando, Deliberto, Michael, Dodla, Syam, Shiratsuchi, Luciano

Assessing Changes in Breakeven Corn Yields from Replanting and Input Price Volatility in 2022

Michael Deliberto, LSU AgCenter Economist

Article Highlights:

• Calculate the breakeven yield required to cover the increase in replanting costs across alternative corn price levels.
• The additional breakeven yield required to offset replanting costs and absorb a 25% increase in the cost of production.

In any ‘normal’ crop year, replanting costs play a substantial role in estimating the additional production cost per unit (bushel). However, inflationary pressures and input price volatility observed since the fall of 2021 have cut into expected profit margins for 2022. The following economic analysis employs a general farm management approach to calculate (1) the breakeven (BE) yield required to cover the increase in replanting costs across alternative corn price levels and (2) the additional BE yield required to offset replanting costs and absorb a 25% increase in the cost of production for corn.

If the farm’s corn yield is expected to be 190 bushels per acre, estimated total variable production costs for corn under irrigation are \$638.11 per acre. The BE yield under these imposed conditions is calculated to be 106.35 bushels per acre, assuming a \$6.00 per bushel price. The BE price is calculated to be \$3.36 per bushel. This can be interpreted to the extent that a producer would need to receive a market price in excess of \$3.36 per bushel to cover the total variable production costs per acre.

Corn planting costs are estimated at \$122.74 per acre. If a producer determines that a field must be replanted, the total variable costs for the growing season will increase from \$638.11 to \$760.85 per acre. The new BE yield under these imposed conditions is calculated to be 126.81 bushels per acre, assuming a \$6.00 per bushel price. This in an increase of approximately 21 bushels per acre to offset the increase in production costs. The new BE price is calculated to be \$4.00 per bushel, an increase of \$0.65 per bushel.

When the market price is varied from \$6.70 to \$4.70 per bushel at a yield of 190 bushels per acre, it is observed from Figure 1 that as price declines, more production is required to cover the increase cost of replanting.

Figure 1. Breakeven (BE) yield comparison across multiple price levels for replanting corn.

By incorporating a 25% increase in the price of diesel fuel and fertilizer unit prices, corn production expenses were estimated to rise by \$72.34 per acre. Coupling production cost volatility and replanting costs, results in Figure 2 illustrate the overall increase in BE yields from replanting a 190 bushel per acre potential field across multiple price levels. As the corn market price declines the required increase in BE yield increases from 29.24 (at a \$6.70 price) to 41.68 bushels per acre (at a \$4.70 price).

Figure 2. Overall increase in BE yield needed to offset corn replanting and incurred input price volatility.

Assessing Changes in Breakeven Soybean Yields from Replanting and Input Price Volatility in 2022

Michael Deliberto, LSU AgCenter Economist

Article Highlights:

• Calculate the breakeven yield required to cover the increase in replanting costs across alternative soybean price levels.
• The additional breakeven yield required to offset replanting costs and absorb a 25% increase in the cost of production.

In any ‘normal’ crop year, replanting costs play a substantial role in estimating the additional production cost per unit (bushel). However, inflationary pressures and input price volatility observed since the fall of 2021 have cut into expected profit margins for 2022. The following economic analysis employs a general farm management approach to calculate (1) the breakeven (BE) yield required to cover the increase in replanting costs across alternative soybean price levels and (2) the additional BE yield required to offset replanting costs and absorb a 25% increase in the cost of production for soybeans.

Under the assumption that the farm’s soybean yield is expected to be 55 bushels per acre, estimated total variable production costs for soybeans under irrigation are \$463.13 per acre. The BE yield under these imposed conditions is calculated to be 37.05 bushels per acre, assuming a \$12.50 per bushel selling price. The BE price is calculated to be \$8.42 per bushel. This can be interpreted to the extent that a producer would need to receive a market price in excess of \$8.42 per bushel to cover the variable production costs per acre.

Soybean planting costs are estimated to be \$74.44 per acre. When a field is replanted, the total variable costs will increase from \$463.13 to \$537.57 per acre. The new BE yield is calculated to be 43.01 bushels per acre, assuming the \$12.50 per bushel price. This in an increase of approximately 6 bushels per acre to offset the increase in production costs. The new BE price is calculated to be \$9.77 per bushel, an increase of \$1.35 per bushel.

When the market price is varied from \$15.00 to \$11.00 per bushel, at a yield of 55 bushels per acre, it is observed from Figure 1 that as price declines, more production is required to cover the increase cost of replanting. As the soybean market price declines the required increase in BE yield increases from 4.96 (at a \$15.00 price) to 6.77 bushels per acre (at a \$11.00 price).

Figure 1. Breakeven (BE) yield comparison across multiple price levels for replanting soybeans.

This analysis incorporates a 25% increase in the diesel fuel and fertilizer unit prices in an attempt to capture the effect that input price volatility has on replanting costs and the required increased number of bushels to offset these incurred expenses. Incorporating price volatility into the enterprise budget, soybean production expenses were estimated to rise by \$28.97 per acre. Coupling production cost volatility and replanting costs, results in Figure 2 illustrate the overall increase in BE yields from replanting a 55 bushel per acre potential field across multiple price levels. As the soybean market price declines the required increase in BE yield increases from 6.95 (at a \$15.00 price) to 9.48 bushels per acre (at a \$11.00 price).

Figure 2. Overall increase in BE yield needed to offset soybean replanting and incurred input price volatility.

Corn Disease Update

Trey Price and Boyd Padgett, LSU AgCenter pathologist

Article Highlights:

• Corn disease identification
• Management considerations

Holcus spot/paraquat drift

Symptoms for Paraquat drift and Holcus spot are similar and are difficult to distinguish from each other. Symptoms appear as round to oval, light tan to white spots with or without yellow halos.Generally, if a drift pattern (gradient) is observed, if affected areas are large and more jagged than round, or if secondary fungi are within lesions, it is likely paraquat drift (Figure 1).If the distribution is random, the spots appear within 48 hours of a thunderstorm, and water-soaking is observed, it is likely holcus spot (Figure 2).Microscopic observation of holcus spot may reveal bacterial streaming, as the disease is caused by Pseudomonas syringae pv. syringae.Both issues are usually of minor concern.

Common rust

Common rust may be the first disease found in corn fields and usually occurs in the lower-to-mid-canopy. Pustules of common rust are brick red to dark orange, somewhat elongated, and will appear on both leaf surfaces (Figure 3).Common rust will progress during relatively cool, rainy, and cloudy weather; however, very rarely are fungicide applications warranted for common rust. Warmer temperatures will greatly slow common rust development.

Southern rust

Southern rust pustules are more orange than brick red, usually not as elongated, and usually appear on the upper surface of leaves (Figure 4). This disease develops in warmer temperatures than for common rust and can continue to develop throughout the growing season. Like common rust, the disease usually initiates in the lower-to-mid-canopy. The disease can reach the upper-canopy during conditions favorable for development. Fungicides may be justified but should be made on a field-by-field basis. The genetic resistance of the hybrid and growth stage (post tassel) and current environmental conditions are factors to consider prior to appling a fungicide.

Northern corn leaf blight

Northern corn leaf blight (NCLB) is a disease usually seen every year in susceptible hybrids (Figure 5).This disease will first appear in susceptible hybrids in fields following corn with reduced tillage.The disease will progress slowly during dry weather, and more quickly during regular rainy periods.Most of the time fungicide applications are not needed for NCLB. However, severe disease may occur in susceptible hybrids following corn in reduced tillage situations.These are the fields that need to be watched closely.

Fungicide considerations

Fungicide application decisions should be carefully considered field by field based on:disease severity (Figure 6), crop stage (Table 1), hybrid susceptibility, fungicide efficacy, tillage regime, prevailing environmental conditions, previous experience, commodity price, and the probability of a return on the investment.If applications are warranted, apply at labeled rates using maximum (5 GPA by air, minimum) water volume is recommended.

Table 1.Percent yield loss (in blue) because of defoliation by crop stage.For example…30% defoliation at dent stage results in a 2% yield loss.

 Growth Stage 10% Defoliation 20% Defoliation 30% Defoliation 40% Defoliation 50% Defoliation 60% Defoliation 70% Defoliation 80% Defoliation 90% Defoliation 100% Defoliation Tassel 3 7 13 21 31 42 55 68 83 100 Silked 3 7 12 20 29 39 51 65 80 97 Silks Brown 2 6 11 18 27 36 47 60 74 90 Pre-Blister 2 5 10 16 24 32 43 54 66 81 Blister 2 5 10 16 22 30 39 50 60 73 Early Milk 2 4 8 14 20 28 36 45 55 66 Milk 1 3 7 12 18 24 32 41 49 59 Late Milk 1 3 6 10 15 21 28 35 42 50 Soft Dough 1 2 4 8 12 17 23 29 35 41 Early Dent 0 1 2 5 9 13 18 23 27 32 Dent 0 0 2 4 7 10 14 17 20 23 Late Dent 0 0 1 3 5 7 9 11 13 15 Nearly Mature 0 0 0 0 1 3 5 6 7 8

Figure 1. Paraquat drift on corn.

Figure 2. Holcus spot of corn.

Figure 3. Common rust.

Figure 4. Southern rust.

Figure 5. Northern corn leaf blight.

Figure 6. NCLB disease severity scale.

Franciele Morlin Carneiro, Post-Doctoral Researcher; Armando Lopes de Brito Filho, PhD student; David Moseley, Soybean Specialist, and Luciano Shiratsuchi, Associate Professor

Article Highlights

• Satellites can support precision agriculture with up-to-date images.
• Satellite images offer many benefits, such as management zones generation, quantification of land use over time, and plant vigor

Satellites are currently one of the leading platforms that support Precision Agriculture. Satellite images are helpful for the management of agricultural activities and generation of management zones. The advantage to using satellites such as MODIS or Sentinel 2 is the images can be captured for an exact date (MODIS) or within two days (Sentinel 2). Another advantage to Sentinel 2 is better resolution (10x10m pixel).

First step: Install the Semi-Automatic Classification Plugin

Figure 1. Installation of the Semi-Automatic Classification Plugin.

Second step – Import the boundary of your area of interest.

Figure 2. Selection and location of your area of interest.

Figure 3. Open the Semi-Automatic Classification Plugin.

Press the “Download options” tab. Pick which satellite and bands you would like to download. At the bottom of this screen on Figure 4 there is a “Download” tab; select “Preprocess images” and “Load bands in QGIS” (Figure 4).

Press the “Login data” tab. If you do not have access to this satellite platform, you can select “Use alternative search for Sentinel-2 (no authentication required)”. If you have accessed this platform, just fill out your username and password and click “remember” for future use (Figure 5).

Sixth Step – Search Sentinel-2 images

Press the “Search” tab and select your area of interest on top of your boundary. Right click starts the selection process and left click ends in the opposite direction. After that, you can see your geographic coordinates enclosing the area of interest. In “Products,” select which satellite to use. Set the start and end date to download images in “Data from” and set your threshold cloud cover “Maximum cloud cover (%)” you want (Figure 6).

Seventh Step – Preview and Import Sentinel-2 images to your laptop

Select the images to download from the preview at the bottom on the right by “Display preview of highlighted images in map.” Double check for too many clouds.

Figure 7.Preview and Import Sentinel-2 imagery to your computer.

Eighth Step – Import Satellite imagery to your computer

This plugin will display images into reflectance, so you can calculate NDVI or other indices.

There are many benefits this tool has to offer, such as management zones generation, quantification of land use over time, and plant vigor. You can contact us if you have any questions.

Leaf tissue testing for determining pre-tassel nitrogen need in corn

Rasel Parvej and Syam Dodla, LSU AgCenter Scientist

Article Highlights:

• Leaf tissue sampling is one of the best indicators of determining N losses after sidedress and pre-tassel N need for maximizing corn yield.
• Leaf tissue sampling should be done from V10 (10 collar leaf stage) to pre-tassel stage.
• The sufficient leaf-N concentration from V10 to R1 (silking) stage should be over 3.1%.

Corn tissue testing is one of the important tools that guides whether pre-tassel nitrogen (N) is required. To evaluate N losses due to excessive rainfall after sidedress, wait until the V10 stage (10 collar leaf stage) and take tissue samples at or after V10 stage. Tissue sampling can be done anywhere from V10 to R1 (silking stage) stages but earlier (V10) would be better if the fields experienced water-logged conditions for several days. For tissue testing, the uppermost fully developed leaf with visible collar below the whorl from 10-15 plants should be collected and sent immediately to the lab for total N concentration. For a large field, several composite tissue samples from the different parts of the field should be collected to better understand corn N status and follow up management. The critical (normal) corn leaf N concentration from V10 to R1 stage is 2.9 to 3.1% (Figure 1). Leaf N concentration below 2.9% would be considered deficient (additional N is needed for maximizing yield) and above 3.1% would be sufficient (no additional N required). Take caution when collecting leaf tissue samples and interpreting N concentration because leaf N concentration can be high due to insufficient plant growth (low dilution) associated with drought, diseases, and pest infestation.

If applying pre-tassel N, the rate should be 15 to 25% of the total N applied i.e., roughly 40 to 60 lb N/acre. Producers can choose either dry (Urea, 46-0-0) or liquid (UAN, 32-0-0, 30-0-0-2S, or 28-0-0-5S) N source. Urea can easily be flown by airplane. UAN should be applied as surface application because high rates of UAN (without water dilution) as foliar application will result in severe foliage burn. However, producers can apply UAN through their pivot irrigation system, if available, as fertigation. Regardless of N sources, it would be better to place N fertilizer close to plant base, if possible, with a high clearance applicator using “Y-drop” to facilitate rapid uptake, minimize N losses, and avoid foliage damage. Application before an expected rain (about 0.25-inch) or pivot irrigation is recommended to incorporate applied N that will minimize volatilization loss. Further, use N-stabilizers (urease inhibitor) to reduce volatilization loss. Experiments conducted at the LSU AgCenter showed that when urea was surface applied at late growth stages, use of N-stabilizer decreased ammonia volatilization losses by 74% and increased corn grain yield by 12 to 25% compared to uncoated urea. Overall, a producer should consider rainfall amount following sidedress N application, field conditions, crop growth, yield potential, and tissue-testing to evaluate N losses and pre-tassel N application.

Figure 1. Critical leaf nitrogen concentration from V10 to R1 stages of corn. (Source: Dr. Trent Roberts, University of Arkansas)

Managing Low Final Soybean Stands

David Moseley, LSU AgCenter Soybean Specialist

Article Highlights:

• Get an accurate final stand count before making replant decisions.
• A final stand count of 100,000 to 135,000 soybean plants is optimum, but a soybean crop can compensate for a lower final stand.
• If the final stand count is between 50,000 to 75,000 plants per acre, inter-planting into the existing stand can be more effective than starting over.

Several factors can lead to a low final soybean stand. If the final population appears to be low, it is good to get an accurate estimate of the final stand count before making replant decisions. To estimate the final stand, random plants from at least ten areas of the field should be counted. For different row spacings, plants from a specific length of row should be counted. To get the average final plant stand, the number of plants counted within a specific length of row should be multiplied by 1,000. (Table 1).

Table 1. To determine final stand, count plants in the length of row corresponding with each row spacing.

 Row Spacing (in) Length of Row to Count Plants (1/1000th of an acre) 7.5 69' 8" 10 52' 3" 15 34' 10" 20 26' 2" 30 17' 5" 36 14' 6" 38 13' 9" 40 13' 1"

In "The Best Soybean Planting Date," data from a multistate collaboration by university Extension specialist suggest a final soybean stand count of approximately 100,000 to 135,000 plants per acre is optimum; where It is recommended to have a higher final stand of soybean in lower yield potential environments. However, soybean plants can compensate for lower than optimum populations.

Furthermore, data from the multistate collaboration suggest there is minimum downside yield risk with a final stand count from 50,000 to 75,000 plants per acre. The results from a population trial at the Dean Lee Research Station in 2020 supports this recommendation. In the 2020 population trial, there was a yield reduction for the May 6 and June 1 planting dates when the final plant stand fell below 61,000 and 67,500 plants per acre, respectively (Figures 1 and 2).

Figure 1. May 6, 2020 population trial at Dean Lee Research Station.

Figure 2. June 1, 2020 population trial at Dean Lee Research Station.

If a replant is considered when the final stand is between 50,000 to 75,000 plants per acre, the general recommendation from the multi-state collaborative research is to inter-plant a variety with a similar maturity group into the existing stand instead of starting over (Figures 3 and 4).

Figure 3. Inter-planting soybean into thin stands.

Figure 4. Mature soybean plants after inter-planting a variety of a similar maturity group into a low original stand.

If considering a replant with a marginal low final stand, caution should be taken since the yield benefits from a larger population may not compensate for the lower yield potential due to a later planting date.

When to Begin Irrigating Corn

Matt Foster, LSU AgCenter Corn Specialist

Article Highlights:

• Corn is very tolerant of water deficit at early vegetative growth stages.
• Soil moisture is the best indicator of when to begin irrigation.
• Irrigation should be scheduled more aggressively as corn approaches tasseling and early reproductive growth stages.

The heat is on! With high temperatures and dry conditions prevalent in most areas of the state during the last couple of weeks, I have received numerous calls concerning corn irrigation. This sudden environmental change to hot temperatures can be a shock for the corn crop and the plant takes time to acclimate. After driving throughout the state, I observed twisting/wilting corn (mainly in the afternoon hours) in many fields. In most cases, the soil moisture was not nearly as limiting as expected. Pulling the trigger on irrigation based on plant wilting is not recommended and premature/excessive irrigation can cause nitrogen loss.

Limiting soil moisture should be the main factor that growers should use to initiate corn irrigation. Rolling or wilting corn leaves are a normal occurrence with lack of rainfall and when temperatures suddenly shift to the upper 80’s and mid 90’s (even with adequate soil moisture). Research has shown that soil moisture is generally plentiful in the soil profile (6 inches and deeper) this time of the year. The Louisiana corn crop varies in age due to a wide range of planting dates, but some of the crop is in young vegetative growth stages. Allowing corn plants to scavenge for moisture in the soil profile will encourage good root development.

Corn growth stage plays a key role in irrigation timing. Corn is very tolerant of water deficit from emergence to V8 (Table 1). Research has shown that little to no yield loss should be expected from water deficiency during early vegetative stages, especially when there is adequate moisture in the soil profile, therefore growers should be more conservative with irrigation until shortly prior to tassel. As corn approaches tasseling and early reproductive stages, irrigation should be planned more aggressively to support increasing crop demands. In general, this transition between irrigation tactics should occur around the V10 growth stage.

Table 1. Average water use by growth stage for 113-day maturity corn. (Modified from Kranz, W.L. et al. 2008. Irrigation management for corn. NebGuide G1850. University of Nebraska-Lincoln Extension.)

 Growth Stage Avg. water use rate (in./day) Total water use during growth stage (in.) Emergence (VE) 0.08 0.8 4-leaf (V4) 0.10 1.8 8-leaf (V8) 0.18 2.9 12-leaf (V12) 0.26 1.8 Early Tassel 0.32 3.8 Silking 0.32 3.8 Blister kernel (R3) 0.32 1.9 Beginning dent (R4) 0.24 3.8 Full dent (R5) 0.20 3.8 Maturity (R6) 0.10 1.4

5/20/2022 7:12:06 PM