Most often the result of heavy rainfall, soil crusting presents itself in the form of hardened soil with a smooth and compacted appearance. Heavy rains following planting along with high heat and winds can cause finely tilled soils with limited residue cover to form a very dense crust. In addition, planting in wet soils and the use of heavy tilling are primary causes of soil crusting. Fine soils and soils with little organic matter are also more susceptible to the condition.  

Soil Crusting Implications  

Hardened soil presents implications for water infiltration while also interfering with crop emergence. The coleoptile of a corn plant acts to protect leaves from emerging before the shoot penetrates the soil. When soil crusting occurs, this can cause leaves to emerge prematurely through the coleoptile below the soil instead of above ground – also known as “leafing out”. When the coleoptile ruptures before penetrating the soil, it becomes much more difficult for leafing out to occur above ground.  

The hypocotyl of the soybean plant may enlarge as it pushes against the crust and can eventually snap and kill the plant. If you notice a swollen hypocotyl, that soybean plant is trying harder than normal to break through the soil.  

A study from Iowa State University found that when 17% of corn plants on a plot exhibited delayed emergence, overall yield was decreased by 4-8%. For soybeans, research from North Carolina State University concludes that delayed emergence reduced overall yield by an average of 14 bushels per acre.   

Leafing Out Identification 

Leafing out is often seen in the form of a “shepherd’s crook” when the coleoptile ruptures prematurely and prevents leafing out above ground. The decreased vigor resulting in premature leafing out can lead to uneven emergence and ultimately reduce yield.  

Adapting Solutions 

No-till or minimum-till can reduce the amount of soil movement in times of heavy rainfall, preventing the onset of crusting. In addition, improving surface soil structure can be done by adding organic matter using cover crops or manure. 

Using a rotary hoe at the depth of the crust can break up the soil, allowing seedlings to emerge. This practice can also act as a means for weed control prior to their emergence. By using a combination of approaches, soil crusting can be eliminated to avoid leafing out below ground. 

Should your plan include the use of a cover crop, here are some considerations to include in that planning process.

Before ordering, take inventory:

1. Did you already apply a herbicide?
2. If yes, what herbicide and does any residual affect which cover crops you can select?
3. To review common watch-outs for herbicide residual, this guide from Penn State University is helpful
4. What is your overall goal?
   • Weed suppression, Erosion Control or Nutrient Fixation for row crop;
   • Or Forage for Livestock

FORAGE OPTIONS

If the main goal is forage for livestock or grazing, timing matters. To receive full prevent plant payment the cover crop must not be harvested before November 1. If the main goal is tonnage, some crop options yield higher quality forage if harvested prior to November 1. Here are some crop options to consider:

Goal: Forage Harvesting After November 1 (for full Prevent Plant Payment)

Cereal Rye, also Winter Triticale, Winter Wheat

These cereal grain options provide fast establishment in dry or wet conditions and good weed suppression. In terms of forage quality, fields planted early to Mid-August will provide best growth, but will start to lose biomass and quality by November 1. All cereals planted earlier than the August time-frame will struggle to overwinter if planted early summer.

Ryegrass and Berseem Clover Mix

When seeded at about 15 lbs/a this cover crop mix can provide the benefit of fast establishment with excellent forage quality. It can tolerate close grazing and has good hay potential. Great weed suppression and a strong fiberous root system help break up layers of compaction. Berseem clovers adds 50-100lbs/A nitrogen to the mix for corn next season. Great before corn.

Goal: Forage Harvesting Prior To November 1 (for maximum forage tonnage and quality)

Oats

Oats are a great option for quick establishment, fast growth and a good palatable feed. We recommend them in a mix with a legume for added livestock benefit. If mixing, consider Oats with Sorghum-Sudangrass and/or turnips for early summer plantings and for late summer Oats with Berseem Clover.

Italian Ryegrass

Italian Ryegrass is another option for fast establishment while providing excellent forage quality. This crop tolerates close grazing and would have good hay potential with its higher tonnage as well.

Sorghum Sudangrass and Pearl Millet

These warm season options can be grazed within 4-5 weeks with medium to high palatability for livestock. These options would also provide high biomass for haying or chopping for silage.

Teff Grass

Teff grass is fast-growing and can be harvested in 60 days. It’s fine-stemmed with medium palatability for livestock feed.

GROUND COVER OPTIONS

Cereal Rye (Overwinters)

As mentioned before cereal rye provides fast establishment in dry or wet conditions and provides great cover for erosion control, weed suppression and organic matter to build soil health.

Ryegrass and Berseem Clover Mix (Winterkills)

When seeded at about 15 lbs/a this cover crop mix can provide the benefit of fast establishment with excellent forage quality. It can tolerate close grazing and has good hay potential. Great weed suppression and a strong fiberous root system help break up layers of compaction. Berseem clovers adds 50-100lbs/A nitrogen to the mix for corn next season. Great before corn.

Oats and Radish (Winterkills)

Oats and radish is another mix that can provide the cover needed for weed suppression when planted anytime from June to August. Fast growth and large amounts of aboveground biomass are perfect for holding onto nutrients from manure applications or fertilizer applied. Great before soybeans.

Berseem Clover: (Winterkills)

Berseem Clover is a quick growing summer annual clover with the main benefit being that it can produce 50-100 lbs/A of nitrogen for the following corn crop.

Disclaimer: There are several options available for prevent plant acres, please contact us at 1-877-GO-LATHAM to inquire about the benefits of different mixes. Be sure to communicate with your crop insurance company to understand the rules and regulations for planting a cover or forage crop before or after your “final plant date” and/or “Late Plant Date” in your state.

Is it time? Tune in to hear Phil Long discuss the question of the season. Is it time to switch corn maturities? #AskTheAgronomist

For corn and soybean plants before and after emergence, flooding and saturated soils can jeopardize yield. Germinating seeds require oxygen to survive. After the first 48 hours following a heavy rain or flooding event, oxygen levels in the soil will become entirely depleted and prevent seeds from germinating and continuing to grow.  

Yield loss for corn and soybeans depends on the duration of the flooding event and at what growth stage it occurs. The longer a plant is submerged or growing in saturated soil, the less likely it is to survive. Generally, smaller seedlings with lower stamina are less likely to survive following a heavy rainfall event compared to larger seedlings. 

Warmer temperatures are associated with higher growth rates, and as a result, a higher amount of oxygen is used. When temperatures exceed the mid-70° range, survival may not exceed 24 hours following the heavy rainfall event. 

Effects on Corn Plants 

Before V6, the growing point is below ground and damage from flooding is more likely to impact yield or kill the plant.  After V6, corn plants fair better in saturated conditions if some of the plant is out of the water. However, the higher temperatures can speed up respiration and oxygen requirements, leading to more plant damage compared to cooler temperatures during a flood event.  

Nitrogen loss is another way flooding impacts corn yields. Corn consumes two-thirds of its nitrogen by the start of the reproductive stage and relies on a functional root system. If a flooding event compromises plant roots, yield can be reduced significantly. Research from Iowa State University found that a 30-inch corn plant that had been flooded for 48 hours with minimal nitrogen uptake experienced a 20% reduction in yield. Flooding can also promote seed decay, crazy top that exhibits proliferated tassels, stunted ears or completely barren plants 

Impacts on Soybeans 

For soybean plants at stages V2 or V3, survival is possible. However, nitrogen fixation can be restricted and reduced yield is still likely. For soybeans submerged for less than 48 hours, yield loss is rarely observed. 

Once the first bloom appears at stage R1 the number of pods per node will be greatly decreased if sitting in saturated conditions. Wilting, stunting and yellow-leaves will be expressed in damaged or dying soybean plants. Further, research has found that greater yield reduction has been observed in soybean plants grown in heavy clay soils as opposed to silt loam soils.  

Assessing Outcomes 

Flooding and prolonged saturated soils pose the greatest threat to young plants that have yet to emerge above ground. As water recedes, any remaining residual mud on corn and soybean plants can reduce photosynthesis. For plants that survive a flooding event, they will be more vulnerable to diseases and stresses over the course of the growing season.  

The survival outlook for saturated seeds and germinating plants will not exceed four days. Plants that survive after water levels recede will continue to grow within three to five days.  

About 60% to 70% of farmland in northwest North Dakota and parts of northeast South Dakota never got planted last year between wet pockets and flooding, says Gary Geske, Latham Hi‑Tech Hybrids’ corn product specialist for the north region.  In the February issue of Midwest Producer, Geske said cropland that was flooded in the previous season needs special considerations during the upcoming growing season.

All crops need N, P and K, but Geske says flood-damaged fields have even more need for fertilizer.  Micronutrients are like vitamins for the crop to keep it healthy in these types of soils.

Another way to help rebuild soils and to help flooded fields recover is by seeding cover crops this spring.  According to an article posted yesterday by Integrated Crop Management NEWS, cover crops can also benefit flood-damage soils in several ways:

• Residue from the cover crop will help reduce soil erosion and crusting.
• The upright cover crop residue will keep wind and sun off the soil surface, reducing wind erosion, sandblasting, and soil water evaporation.
• Growing roots of the cover crop will help feed the soil biological life.

For more information about crop selection, seeding rates and methods, click here.

Iowa State University’s Mahdi Al-Kaisi, in the November 7^th issue of Integrated Crop Management News, offers management considerations for farmers whose soils were affected by the Floods of 2011.

“Farmland in western Iowa and eastern Nebraska affected by flooding early this year and not planted to any crop has potential economic and soil environmental consequences if the soils are left unattended,” writes Dr. Al-Kaisi.  “Long-term damage to soil in areas of significant flooding need to be considered when planning for next season’s crop.”

Al-Kaisi says these aspects should particularly be managed for previously flooded soil:

• Land Leveling and Sand Cleaning
• Soil Testing
• Cover Crop

For more information about each of these management aspects, click here to download Al-Kaisi’s entire article on “Management Considerations for Post Flooding Soils.”

The article stated Iowa’s 2010 corn crop has fallen from 72% in the good-to-excellent category to 66% due mainly to flooding and excessive rainfall this past week. Similarly, the state’s soybean crop has dropped from 66% in the good-to-excellent category to 64%, according to the government’s weekly weather and crop conditions report released July 6.

The article adds that approximately 8% of Iowa corn crop is tasseled and silking and 27% of Iowa’s soybean crop has bloomed, proving to be good news for soaked Iowa farmers.

Northeast and North Central Iowa areas had a moderate spring but were soaked when they received large amounts of rain this week — the Waterloo area receiving 7 inches in two days.

John Holmes, an Extension field agronomist for Iowa State University, says that in northern Iowa, “We have anything from really nice looking corn that is now tasseling and silking to corn that is probably just over knee-high and is pale yellow and really looks marginal. Not very pretty at all.”

Holmes added, “It’s easy to drive down the road and see the problem fields—and get a distorted picture of the whole county. Keep in mind we do have areas in Iowa, even here in the soggy parts of north central and central Iowa, that are going to produce some tremendous amounts of corn this fall. Some of these fields this summer are indeed looking very nice. However, in other areas of the state—such as in southeast and south central Iowa—they’ve have had one problem after another this year, mainly due to the very heavy amounts of rainfall they received throughout June and into July.”

Click here to read the full article.