Breaking Hard Pan Soil: Techniques For Success

Hardpan is a layer of soil so dense that air, water, and roots can barely pass through it. It is usually found 2 to 4 feet under the surface, although it can be located anywhere from 4 to 40 inches below. Hardpan can be caused by human activity, such as repeated plowing or heavy traffic, or it can form naturally due to deposits of silica, iron oxides, salt, or calcium carbonate fusing and binding soil particles. This layer of soil can cause issues in farming and gardening by impeding drainage and restricting root growth, leading to reduced crop yields. To address hardpan, mechanical methods such as digging, plowing, or subsoiling can be employed to break up the dense layer. Alternatively, soil amendments can be used to alter the soil structure and promote the dissolution of the hardpan over time.

Using mechanical means like digging or plowing

Breaking up hardpan mechanically can be done through digging or plowing. This can be done manually or with the help of heavy equipment.

A broadfork is a manual tool that can be used to break up hardpan. A digging fork or a spade can also be used for this purpose. For larger jobs, a chisel plow can be used to rip through the hardpan layer. This can be done with the help of a tractor. Chisel plows penetrate and pull the compacted layer of soil upwards, shattering it into pieces.

In areas where a chisel plow cannot be used, a backhoe can be used instead. Even a small backhoe can quickly break through hardpan by digging several holes to allow for drainage. Softer pans, such as plowpan or claypan, can be dug through with a shovel, perhaps with the help of a pick. Claypan should be broken up when it is wet.

Subsoiling is another method of breaking up hardpan. This involves deep tillage, extending about 12 to 18 inches below the soil surface to break up the compacted layer. Conventional tillage, which is only about 6 to 8 inches deep, is often too shallow to reach the layer of compacted hardpan soil. Subsoiling improves soil aeration and drainage, reducing standing water, flooding, runoff, and topsoil erosion.

However, it is important to note that excessive subsoiling can result in the soil becoming too soft and absorbing too much water, potentially leading to root rot. Additionally, plowing or using an aerator may not be the best approach, as aeration can damage root structures.

Using soil amendments to alter soil structure

Hardpan is a dense layer of soil that is largely impervious to water. It is usually found 2 to 4 feet under the surface, and it can be caused by soil composition or human activity. To get rid of hardpan, you can either break through it or leave it and garden on top of it.

Using soil amendments is one way to break up hardpan. Soil amendments are any materials added to the soil to improve its physical properties for plant growth, such as water retention, permeability, water infiltration, drainage, aeration, and structure.

• Add organic matter : Finished compost, well-rotted leaves, and other natural materials can be worked into the soil to improve the way soil particles fit together and increase the activity of beneficial microorganisms. Avoid using fresh wood products as they can tie up nitrogen in the soil and cause nitrogen deficiency in plants. Instead, use composted wood chips and bark, which can help aerate dense, compacted soil and create spaces for plant roots, water, and nutrients to move through more easily.
• Use inorganic amendments : Inorganic soil amendments are typically used for specialty growing and are tailored to the type of garden being designed. Rock and gravel, for example, can be added to garden beds to improve drainage. However, scientific papers provide mixed conclusions about this practice, as adding gravel can sometimes make drainage worse.
• Adjust the soil pH : Acidic soils are most often affected by hardpan due to the propensity of certain mineral salts, such as iron and calcium, to form hard complexes with soil particles under acidic conditions. Adjusting the soil pH with lime can help to break up hardpan.
• Add gypsum : Gypsum can help modify the soil structure without significantly changing the soil pH. It increases water penetration, loosens compacted clay soils, and promotes easier root penetration.
• Add coconut coir : Coconut coir is a popular and inexpensive soil amendment that can improve the soil's ability to retain water and nutrients. It is also a renewable alternative to sphagnum moss and peat moss.
• Add vermiculite : Vermiculite is a finely crushed mineral that helps the soil retain water and nutrients. It also promotes root growth and facilitates the anchoring of young roots.
• Add pea gravel : Working a 2-inch layer of pea gravel into clay soil can help to open up spaces for plant roots, water, and nutrients. Pea gravel can also help stabilize soft, slippery soils that are prone to erosion.

It's important to note that breaking up hardpan through the use of amendments may require action over the course of years, and success is not guaranteed. Before adding any amendment to the soil, it is recommended to do a soil test to get accurate data and amendment recommendations.

Adjusting soil pH with lime

Lime is used to correct soil pH by reducing acidity and increasing alkalinity. Most plants grow best in soil with a pH between 5.5 and 6.5. If the pH is too high or too low, plants cannot absorb the necessary nutrients from the soil.

The amount of lime required depends on the initial pH and the type of soil. Sandy soils will need less lime than clay soils to achieve the same shift in pH. A soil test can be carried out to determine the pH level and the amount of lime needed. Home pH test kits are available, but for specific recommendations, a professional soil analysis is required.

Types of Lime

There are three main types of lime used to adjust soil pH: garden lime, dolomite lime, and hydrated lime. Garden lime is the most common and is sourced from ground limestone, calcified seaweed, and ground chalk. Dolomite lime is also derived from ground limestone but is rich in magnesium carbonate, which adds magnesium to the soil. Hydrated lime, or calcium hydroxide, is a fine powder commonly used in construction. It is the fastest-acting type of lime but can be irritating to the skin, lungs, and eyes, and it kills earthworms. Dolomite lime and garden lime are safer options and can also add micronutrients to the soil.

How to Apply Lime

Lime should be applied in the early winter for annual crops, giving it time to take effect before spring planting. For perennial plants, lime can be added when planting, or periodically in small amounts. It is important to ensure maximum contact between the lime and the soil. Lime can be mixed into the soil using a broadfork or hand-tiller, or spread on the surface and watered into the soil.

It takes about four weeks to see a measurable difference in soil pH after adding lime, but it can take up to twelve months for the lime to fully dissolve and incorporate into the soil. The effects of lime can last for 2 to 3 years.

Adding gypsum to loosen clay particles

Hardpan, or soil pan, is a dense layer of soil that is largely impervious to water. It is usually found below the uppermost topsoil layer. Clay particles are some of the smallest particles commonly found in soils, and their structure creates small spaces between individual particles, which restrict the passage of water, reducing infiltration and drainage. Soils with a high clay content are also easily compacted and affected by man-made discharges.

Gypsum is a mineral that can be used to improve the physical structure of clay soil. It is a simple chemical called calcium sulfate (CaSO4) and is used to make drywall gypsum board. It contains calcium ions and sulfate ions, both of which are plant nutrients. Gypsum can be easily applied to the soil surface with a regular lawn spreader. It improves soil structure and relieves compaction in lawns and gardens.

When applied to alkaline soils, gypsum helps to break up the soil into smaller, crumblier pieces, improving drainage. This is particularly beneficial for heavy clay soils, which can become waterlogged, and where nutrients can become bound to the clay, making them unavailable to plants.

To use gypsum on your lawn, first aerate your lawn by poking holes all over the lawn area with a garden fork or lawn aerator. Alternatively, you can hire a rolling aerator for larger areas. Next, spread 1 to 2 kg of gypsum for every square metre of lawn. Rake in the gypsum and water well. Autumn or winter are the best times to do this, as it will give the gypsum time to work on the soil structure before the grass grows back in spring.

It is important to note that gypsum should be applied in the recommended quantities. If you add too much gypsum, it can result in the elimination of essential minerals such as iron, magnesium, and manganese.

Using products like MycorrPlus to activate carbon sequestration

Hardpan, or soil pan, is a dense layer of soil that impedes drainage and restricts the growth of plant roots. It is usually found below the uppermost topsoil layer and is largely impervious to water. Hardpan can be caused by deposits in the soil that fuse and bind soil particles, such as dissolved silica, iron oxides, and calcium carbonate, or it can be man-made, resulting from compaction due to repeated plowing, heavy traffic, or pollution.

One way to get rid of hardpan soil is by using products like MycorrPlus, which activate carbon sequestration and promote healthy soil and plant growth. MycorrPlus is a combination of Soil Balance and GroPal. Soil Balance helps to balance nutrients and energies in the soil, while GroPal, a sea mineral concentrate, provides macro and trace minerals beneficial to plants.

Breaking Down Compacted Soil

MycorrPlus introduces beneficial bacteria and mycorrhizal fungi to the soil, which help to break down compacted soil and improve soil structure. These microorganisms create an aerobic membrane that holds and balances nutrients, promoting the formation of aggregates that improve soil aeration and moisture retention.

Removing Salts

Hardpan can be caused by the presence of salts such as sodium ions in the soil. MycorrPlus contains salt-remediating microbes that help to flush out these salts, reducing their sterilizing effect on the soil.

Improving Drainage

By improving soil structure and promoting the formation of aggregates, MycorrPlus helps to enhance drainage. This reduces standing water, flooding, and soil erosion.

Increasing Nutrient Availability

MycorrPlus increases the availability of nutrients to plants, including nitrogen, phosphorus, sulfur, calcium, and trace minerals. This, in turn, promotes healthier plant growth and reduces the need for chemical fertilizers.

Adjusting Soil pH

MycorrPlus helps to adjust the soil pH to a near-neutral level, making nutrients such as sulfur more available to plants. This is especially important as lime, often used to increase soil pH, can reduce sulfur availability.

Promoting Root Growth

By improving soil structure and nutrient availability, MycorrPlus enhances root growth. This helps to break through hardpan and access deeper soil layers for water and nutrients.

Overall, MycorrPlus is a powerful tool for activating carbon sequestration and promoting healthy soil. By following the guidelines for application and giving it time to work, farmers can effectively get rid of hardpan soil and improve their crop yields.

Frequently asked questions