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Serving: IA
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FLOODED SOIL: Soil may experience “post-flood syndrome” similar to fallow syndrome, where land is left unplanted to any crop for an entire season.

Soil health is plant health: Restoring post-flood fields

Damage to soil in fields where flooding occurred needs to be considered when planning for next year’s crop.

Intense flooding last spring led to widespread field damage across much of the Midwest. Iowa had over 463,000 prevented planting acres in 2019, according to USDA. Growers should consider the effect those unplanted acres could have going into the 2020 season.

Fields left saturated will be low in nutrients as a result of not having a crop to keep soils productive. Often, the affected fields show classic symptoms of phosphorus deficiency, such as slow-stunted early growth, purple coloration and poorly developed roots. This condition is often called fallow syndrome. It can occur when fields get their next crop after sitting empty for a season and is especially problematic in corn. 

Reduction of soil biology

Many beneficial fungi may also disappear from the empty soils without a host, which can hinder crop and root growth for subsequent seasons. One of the beneficial fungi that can die off in the off-season is called mycorrhiza. Mycorrhiza are extremely useful to crops by supporting the soil and encouraging plant roots to develop.

Mycorrhizae help with many yield-boosting practices, including nutrient and water uptake and storage for proper growth throughout the season. Without these fungi, which build up in soils naturally over time, soil health, plant health and yield can be stunted. Once mycorrhizae colonies are destroyed, they can take a long time to rebuild since they require a living root to grow from.

Boost soil health before spring

Mike Riffle, product development manager for soil health brands at Valent, suggests growers take steps now to prevent fallow syndrome from occurring next year in damaged fields. Follow these tips if you left fields fallow in 2019, or for any soils needing a boost:

Soil test now. Know where you stand with nutrients in your fallow fields. Now is the time of year to test the soil and find out what your soils are lacking.

Take testing to the next level. Riffle suggests checking out the Cornell Comprehensive Soil Assessment on top of a traditional soil test. This test includes measurements of soil biology, whereas a traditional soil test focuses on physical and chemical properties. The soil health assessment test measures available water capacity, ACE soil protein index, respiration and active carbon, and lists any constraints in any of the areas.

Practice soil conservation in the off-season. “Doing things like conservation tillage or planting cover crops aid in preserving plant available nutrients like phosphorous and nitrogen to support healthy crop development” says Riffle. Always having roots growing in your fields will help keep beneficial fungi like mycorrhiza alive and well.

Consider a product to give soils a boost: MycoApply EndoPrime SC from Valent U.S.A. contains four species of mycorrhizal fungi that colonize with newly planted crops and expand root absorption area to help improve nutrient efficiency, drought tolerance and protect yield potential throughout the season.

In a 2017 Valent trial of three corn plots with low P levels (below 20 ppm), there was on average a 7.1-bushel-per-acre yield increase on plots treated with MycoApply EndoPrime SC as opposed to untreated sites.

For more information on MycoApply EndoPrime SC, talk to your local Valent rep or visit

Source: Valent, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.




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