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The Soil Health Exchange is a new online forum from CropWatch, designed to give producers and ag industry stakeholders the opportunity to speak directly to experts about their questions and concerns regarding soil health topics.

Below, our team of soil health specialists address a recent question from the public.

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Question:

"I handle a trust that has some unique soil; some of it is gumbo, and some is better black and sand. Most are under pivot. I need some help with how to deal with this to improve the soil and be able to keep it under pivot. We had it tiled a few years ago, but it did not work, and we’re unsure whether it was properly installed. I am open to ideas for improving the field. It was not good when they got two combines stuck there this fall.”

Current Status and Situation on Ground: The trust land encompasses diverse soil types, notably gumbo, black, and sandy soils, which pose distinct challenges in water management, especially under pivot irrigation. The attempt to improve soil drainage through tiling has been unsuccessful, leading to operational issues such as combines getting stuck due to waterlogging. This is particularly evident in the two low-lying areas, indicating these zones are most affected by excessive moisture retention.

Ground Situation Details and Potential Challenges

1. Crop Rotation Practices:

• Current practice involves a corn/soybean rotation without cover crops. This can lead to reduced soil organic matter and structure, contributing to waterlogging issues.

Residue Management:

• Corn residue is regularly harvested, which may diminish the soil's natural resilience against compaction and erosion, further exacerbating water retention problems.

Equipment and Harvest Challenges:

• Heavy machinery, such as combines, has gotten stuck multiple times due to wet and heavy soils, indicating significant waterlogging.
• Tillage is routinely performed to correct ruts from harvest equipment, which can disrupt soil structure and contribute to the formation of compaction layers.

Deep Tillage Interventions:

• In a previous dry year (2022), deep tillage by a bulldozer ripper in wetter areas prior to planting allowed for better drainage and successful planting and harvesting.
• However, in the current year, despite planting through wetter spots, the east spot could not be harvested, suggesting that deep tillage is not a sustainable or reliable solution for the waterlogging problem.

Drainage System Issues:

• Field tiling installed several years ago has never functioned properly, indicating possible incorrect installation or design for the specific soil and site conditions.

Soil and Management Details

1. Soil Type and Drainage Issues:

• Gumbo Soil: Dense, clay-rich soil that is prone to waterlogging due to its low permeability, which hinders water infiltration and drainage. When wet, it becomes very sticky, which can immobilize heavy farm equipment.
• Black Soil: Typically fertile with better water retention but may still present drainage issues if the structure is compromised.
• Sandy Soil: Drains well but can be nutrient-poor and may require different management to maintain soil moisture levels under pivot irrigation.

Pivot Irrigation Management:

• The pivot irrigation system, while efficient for water distribution, can exacerbate waterlogging in soils with poor drainage like gumbo. Adjustments to irrigation scheduling and amounts are necessary to prevent overwatering and saturation.

Previous Tiling Efforts:

• The installed tiling system did not function as intended, possibly due to incorrect installation or inadequate design for the specific soil types and conditions present on the land.

Equipment Challenges:

• The recent incident of two combines getting stuck indicates that the current field conditions are not suitable for standard heavy machinery operations, especially during wet periods.

Reasons for Exacerbated Wetness and Solutions

Soil Structure and Bulk Density:

Cause: Intensive tillage and the naturally high bulk density of the soils are leading to a poor soil structure. This can cause waterlogging as the soil becomes too compact to allow proper water infiltration and drainage.

Solution:

• Reduce tillage to improve soil structure. This can help increase pore size and enhance water infiltration.
• Consider crop rotation with deep-rooting plants, such as alfalfa, to naturally aerate the soil and improve porosity. As the roots decay, they leave channels that can enhance water and air movement.

Compaction Layer (Plow Pan):

Cause: Tillage, especially when repeated at the same depth, can create a compaction layer just below the tilled layer. This plow pan restricts water and air movement, exacerbating waterlogging.

Solution:

• Transition to less or no-tillage practices to avoid the formation of a plow pan.
• Implement subsoiling periodically where necessary, but with caution to avoid repeating the cycle of compaction.

Organic Matter Levels:

Cause: Regular residue removal and a narrow crop rotation have likely led to reduced levels of organic matter, contributing to higher bulk density and poorer soil structure.

Solution:

• Incorporate cover crops into the rotation. Even if there has been reluctance based on past experiences, certain cover crops can be chosen that dry out the soil enough for planting and improve soil structure over time.
• Apply manure to increase organic matter, which can help reduce bulk density and improve soil aggregation.

Innovative Farming Practices:

Cause: Traditional farming practices may not be addressing the unique challenges of the field.

Solution:

• Experiment with perennial cover crops like clover, which can be planted with cash crops.
• This can reduce input costs and provide grazing opportunities. Set up a trial area to test this approach without committing the entire field immediately.

Re-evaluating Tiling and Soil Movement:

Cause: Previous tiling was likely ineffective due to improper installation, and simply moving soil from higher to lower spots may not address underlying drainage issues.

Solution:

• Before redoing the tiling, consider other practices as mentioned above. If tiling is reconsidered, ensure it is properly designed and installed by a professional.
• Avoid moving soil as it could lead to the loss of topsoil quality and create new issues.

Additional Considerations:

Soil Testing:: Conduct comprehensive soil testing to understand the current organic matter levels, bulk density and water infiltration.

Yield Mapping: Review past yield maps to identify the size and impact of the problem areas.

On-farm Research: Utilize the field as an on-farm research site to test different solutions and document the results.

Detailed Action Plan and Timeline

1. Immediate Actions (0-3 months):

• Engage a soil specialist for an in-depth soil health assessment.
• Begin reduced tillage practices and plant cover crops immediately following the current harvest.
• Apply organic amendments like compost or manure to the most affected areas.

Short-term Actions (3-12 months):

• Analyze soil test results and create a tailored soil amendment program.
• Implement subsoiling, if necessary, based on specialist recommendations.
• Start a pilot program for perennial cover cropping in a section of the field.

Medium-term Actions (1-2 Years):

• Expand successful pilot practices to larger areas of the farm.
• Continue monitoring soil health and adjusting management practices accordingly.
• Reassess the need for re-tiling based on soil health improvements and drainage changes.

Long-term Actions (2-5 Years):

• Establish a sustainable crop rotation that includes a variety of deep-rooting crops and cover crops.
• Evaluate the long-term benefits of reduced tillage and the potential transition to no-till farming.
• If necessary, redesign and install a new tiling system with professional oversight.

Monitoring and Evaluation Strategies:

1. Soil Health Indicators:

• Monitor indicators such as bulk density, soil organic matter and water infiltration rates at regular intervals.

Crop Performance Metrics:

• Record yields and crop health data to correlate with changes in soil management practices.

Waterlogging Incidences:

• Document the frequency and severity of waterlogging and machinery challenges to evaluate the effectiveness of the implemented solutions.

See more Soil Health Exchange

Soil Health Exchange Team At A Glance

Experts for this week's forum:

Saurav Das
Research Assistant Professor
UNL Department of Agronomy and Horticulture

Leslie Johnson
Animal Manure Management Extension Educator
Nebraska Extension

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