Agrii Tramlines Podcast | Season 3, Episode 21

How do farmers approach their soils this spring to maximise crop performance in this very challenging season?

Below is a summarised report from our recent Tramlines Podcast episode about Managing Wet Winter-Worn Soils this spring.

The UK experienced an exceptionally wet winter in 2022, leading to widespread flooding and severely impacted farmland. Many fields remain waterlogged, with soils saturated far beyond field capacity.

This has major implications for spring planting, as overly wet soils are easily compacted by heavy machinery. Compaction destroys soil structure and reduces yield potential. Farmers face difficult decisions this spring about how to plant crops without causing lasting damage to their soils.

With fields in such a fragile state, standard practices like deep tillage are off the table. Farmers need creative solutions to establish spring crops in a way that protects and nurtures the soil.

Careful assessment of each field is required, along with strategic use of lighter equipment and low-disturbance techniques. Patience will also be key, as fields may not be ready for planting on the usual timeline.

This is a challenging situation, but also an opportunity to demonstrate environmental stewardship. With proper soil management, farmers can plant successful crops while safeguarding the soil's long-term productivity. The decisions made this spring will impact soil health and farm sustainability for years to come.

Assessing Soil Conditions

When it comes to assessing soil conditions this spring, the first priority should be checking where water is draining from each field. Ensure drainage ditches and tile drainage outlets are free of debris so water can flow off the field. With the extreme wetness many fields have experienced, soil structure and friability need careful evaluation before travelling on the field with heavy machinery.

A simple but effective assessment is to dig holes throughout the field and analyse the soil structure at different depths. Check for any compacted or smeared layers near the surface. Take samples of the soil and roll between your hands to check for friability. If the soil easily forms a worm-like shape that then crumbles, it is likely dry enough to work. However, if it sticks together in a solid mass, the field may need more time to dry out. You can also use a soil penetrometer to check for compaction deeper in the soil profile.

The time of day will impact assessments, as soil often dries out by afternoon after a morning of sunlight and wind. It's advisable to travel fields later in the day if possible. Careful analysis of soil moisture and structure will ensure fields are not damaged by early traffic when soils are still waterlogged. Preventing compaction now will pay dividends during the rest of the cropping cycle.

Understanding Soil Fragility

Soil fragility refers to the delicate state of soil after prolonged wet or flooded conditions. When soils become saturated for extended periods of time, especially during the winter, it can alter the soil structure and stability. As described by the experts, fragile soil tends to have:

• A surface crust or compacted layer from heavy rains pounding down. This can be 3-4 inches of compacted silt or soil.
• Weakened soil structure and air pockets replaced by water deeper in the profile, if deep cultivations were done.
• A failed crop residue present, along with residual herbicides, etc. from the previous growing season.

Fragile soil has a massive impact on newly planted crops and their ability to establish. The weakened soil structure cannot properly support crop roots as they try to develop and take hold. Any crusting or compaction also inhibits seedlings from emerging evenly.

As soil dries from its saturated state, fragile soils are prone to cracking or clodding up. This can expose seeds or damage young roots. The lack of stability and structure prevents roots from accessing nutrients efficiently or maintaining consistent contact with moisture and oxygen.

Overall, fragile soils create very poor growing conditions for crops. Trying to force crop establishment before soils have reconstituted themselves leads to patchy germination, stunted plants, and opens the door for weeds and disease. Taking the time to properly prepare fragile soils pays dividends in achieving optimal crop performance.

Soil Differences by Type

Soil types behave differently when wet. Clay soils tend to get very sticky and clod easily when wet. Clay particles are tiny and pack tightly together when wet, creating a dense, impermeable layer.

Other soil types like sandy loam and silt loam have more space between particles so water can infiltrate more easily. They tend to be more friable than clay soils. Friable means the soil crumbles easily when handled.

With clay soils, a farmer may roll a sample in their hands and it stays in a solid lump rather than breaking apart. This indicates the soil is too wet for field work. Clay soils are easily compacted when worked on wet, leading to poor drainage and stunted crop growth when soils dry and crack.

Fields with lighter soil types like sandy loam may be drier sooner after rain events. The farmer can assess each field by soil type, along with drainage and prior tillage, to determine which are ready for spring planting first. Fields with poor drainage or compacted clay soils may need more time to dry adequately. Careful assessment ensures the best soil conditions for planting.

Field Prioritisation

Assessing soil conditions is critical for deciding which fields should be prioritized for operations this spring. With many fields still holding excess moisture, farmers need to determine where drainage can be improved and water movement accelerated.

Drainage ditches and tile outlets should be inspected first and any debris blocking water flow should be removed. Functioning drainage systems are key to helping saturated fields start to dry out. Fields with poor drainage that are slow to shed water will need extra time to dry before field work can begin.

Once drainage is optimised, focus should shift to fields that are showing signs of improved conditions. Digging test holes and examining soil structure by hand can provide a good indication of which fields are approaching proper friability. Rolling wet soil into a worm shape can demonstrate if a field is still too wet and at risk of compaction, versus one where the soil starts breaking down more readily.

Targeting fields as they approach ideal moisture levels will provide the best soil conditions for operations. With timely drainage improvements and visual soil assessments, farmers can prioritize their land and avoid causing unnecessary compaction damage this spring.

Machinery Setup

Proper machinery setup is critical for minimizing soil compaction when working wet fields in the spring. Two key factors to consider are power-to-weight ratio and tire pressure.

The power-to-weight ratio affects how much weight from the tractor transfers to the soil. For spring tillage and drilling operations, aim for a ratio around 45 kg per horsepower. Avoid going over 50 kg/hp as that puts too much weight on the soil.

To find the ideal weight, multiply the tractor horsepower by 45 (or 50) kg. Then set the tractor weight accordingly through ballasting. Make sure to distribute the weight properly with 60% over the rear axle and 40% over the front. The front axle causes the most compaction, so overload it.

Tire pressure also greatly impacts soil compaction. For spring field work, try to get axle weights below 6 tons and tire pressures below 10 psi. Lower pressures increase the tire footprint and reduce ground pressure. Radial tires and high-flexion tires allow even lower pressures.

Properly setting up machinery is time well spent. Calculating power-to-weight ratios, adjusting ballast, and lowering tire pressures prevent unnecessary soil compaction and pay dividends during crop growth. Work smart to minimize compaction and field damage this spring.

Avoiding Soil Compaction

When soils are wet and fragile, it's critical to avoid compaction that can damage soil structure. Compaction occurs when heavy machinery exerts excessive pressure, compressing the soil and reducing pore space. This can restrict root growth, limit oxygen and water infiltration, and reduce yields.

There are several steps farmers can take to minimise compaction:

• Carefully consider tractor and implement weights. Striking an optimal power-to-weight ratio prevents overloading axles. Ideally, aim for around 45kg per horsepower when drilling fragile soils.
• Distribute weight appropriately between axles, with 60% over the rear and 40% over the front. The front axle does the most compaction, so avoid overloading it.
• Reduce tire pressures, especially on the front axle. For spring drilling, try to get axle weights below 6 tonnes and tire pressures below 10psi. Flexible low-pressure tires significantly reduce compaction.
• Limit unnecessary field traffic and repeat trips. When possible, apply fertilizer or pesticides during initial field operations.
• Avoid wet fields altogether until they've dried sufficiently. Test soil conditions regularly by digging, using a penetrometer, or squeezing soil in your hands.
• Consider controlled traffic techniques to confine all machinery loads to permanent traffic lanes. This prevents compaction of the entire field.

With careful weight management and traffic control, farmers can drill successfully this spring while protecting fragile soil structure for the future. Minimizing compaction ensures healthy root development and reduces the need for deep tillage later.

Direct Drilling Considerations

It's important to reflect on learnings from past direct drilling trials when considering spring planting approaches. As one expert noted, they conducted trials on fields that traditionally used deeper tillage methods rather than direct drilling.

When they attempted to direct drill into wet soil conditions, drills that moved more soil and planted deeper performed better than those doing shallow slots or direct drilling. This indicates the soil conditions weren't suitable for direct drilling.

The takeaway is that if the soil structure and field conditions aren't right, it's better to prepare the field in the fall rather than force spring planting. There are ways to manage fields through cover crops and rotational grazing to reset the soils if direct drilling isn't viable.

Evaluate soil conditions, realistically assess which fields can support direct drilling, and utilize lighter drills or different implements as needed to protect fields for this year's crop and long-term soil health. With careful assessment and management, fields can be productively planted this spring while stewarding the land for future growing seasons.

Soil Management Tips after a Wet Winter

With soils in many areas above field capacity and in a fragile state, farmers need to take care in preparing fields for spring planting.

Some key points to consider:

• Assess each field individually - dig holes, feel the soil, check drainage. Prioritize fields that are drier and have better structure.
• Pay close attention to machinery setup to avoid compaction. Consider power to weight ratio, weight distribution, and tire pressures. Lighter equipment or controlled traffic may be preferable.
• Be realistic - some fields may not be suitable for planting this spring due to wetness. Consider alternative crops or leaving fallow.
• Improve drainage where possible - clear ditches, install tile drainage. Ensure water can move off fields rapidly when dry weather arrives.
• For direct drilling, ensure soil structure is resilient enough. A false seedbed approach may help dry and firm the top layers.
• Focus on minimizing soil disturbance this spring. Consider minimal or zero tillage and avoid deep cultivations where possible.
• Plant cover crops on marginal or fallow fields to protect and improve soils. Multi-species mixes can provide multiple benefits.
• Work in short windows when conditions are optimal - often the afternoons as moisture evaporates. Be prepared to stop if soils get damaged.
• Getting the basics right - soil assessment, drainage, machinery setup - will give crops the best possible start this spring despite challenging conditions. Careful soil management now protects long term productivity.