3.1 Soil Removed, Stockpiled, and Spread

▶ Condition to be modified: Existing soil that is suitable for reuse as Planting Soil (see Soil Definitions) but is in the wrong place of elevation, or cannot be adequately protected during construction. Soil is to be harvested, stockpiled and re-spread with or without further modifications as indicated.

▶ How to modify this condition: Excavate existing soil from the areas designated for planting or other construction on the drawings, and stockpile them (See 1.1 Storage and Handling). Excavate soil using equipment and methods that preserve the clumps and peds (see Soil Definitions) in the soil. Generally this means using the largest piece of equipment that is practical for the project size and scope. Respread soil as outlined in 0.0 - XXXX.

 

3.2 Tilling

▶ Condition to be modified: Surface soil compaction to a maximum of 6 inches deep from traffic or light grading. The original ‘A’ horizon (top layer of soil - topsoil) may have been previously removed or graded but deeper soil horizons have remained intact with acceptable compaction levels and limited grading. The soil’s organic matter, pH, and chemistry in the A horizon may not be suitable for the proposed plants and may need to be modified as required.

▶ How to modify this condition: Till the top 6 inches or deeper of the soil surface with a roto tiller, spade tiller, ripper or agricultural plow. Spread 2 - 3 inches of Compost (See Soil Definitions and Section 2.4) on the surface of the tilled soil and make any chemical adjustment as recommended by a soil test.  Till or disk the compost into the loosened soil. Smooth out grades with a drag rake or drag slip.

 

3.3 Radial Trenching

▶ Condition to be modified: Surface soil compaction to a maximum of 24 inches deep from traffic or light grading. The original A horizon (top layer of soil - topsoil) may have been previously removed or graded, but lower profiles below 24 inches have remained intact with acceptable compaction levels and limited grading. The soil’s organic matter, pH, and chemistry in the A horizon may not be suitable for the proposed plants and may need to be modified as required.

▶ How to modify this condition: Using a trenching machine, dig trenches to the extent and depth shown in the detail. Backfill the trench with the soil removed from the trench. Add additional site soil if needed to fill the trench to be flush to the existing grade after the soil settles.

 

3.4 Ripping and Fracturing

▶ Condition to be modified: Deep soil compaction the result of previous grading, filling, and dynamic or static compaction forces. The original A horizon (top layer of soil - topsoil) is likely removed or buried. The soil organic matter, pH, and chemistry in the A horizon is likely not suitable for the proposed plants and should be modified as required. These methods require large equipment.

▶ How to modify this condition (Ripping): After grading and removing all plants and debris from the surface, using a tracked dozer or similar large grading equipment, loosen the soil by dragging a ripping shank or chisel thru the soil to depths of 24 inches with ripping shanks spaced 18 inches or less apart in two directions. The number of shanks per pull is dependent on the degree of soil compaction and the size of the dozer. Spread 3-4 inches of Compost over the ripped area and till into the top 6 inches of the soil surface.  Do not start planting into the ripped soil until the soil has been settled.

▶ How to modify this condition (Fracturing): After grading and removing all plants and debris from the surface, spread 2 – 3 inches of Compost over the surface of the soil. Loosen the soil to depth of 18 - 24 inches, using a backhoe to dig into the soil through the Compost. Lift and then drop the loosened soil immediately back into the hole. The bucket then moves to the adjacent soil and repeats the process until the entire area indicated has been loosened. Spread 3-4 inches of Compost over the ripped area and till into the top 6 inches of the soil surface. Do not start planting into the fractured soil until the soil has been settled.

▶ How to modify this condition (Trenching): After grading and removing all plants and debris from the surface using a chain trenching machine, dig 24-inch deep trenches, 24 inches apart, across the entire area. Maintain an 18-inch standoff from the edges of all curbs, paving and structures. Backfill the trenches with Compost.

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3.5 Low Organic Matter 

▶ Condition to be modified: Soil with low organic matter and/or a missing A horizon (top layer of soil - topsoil). The soil is not compacted except for some minor surface compaction. The soil organic matter, pH, and/or chemistry are likely not suitable for the proposed plants and should be modified as required.

▶ How to modify this condition: Spread 3 - 4 inches of Compost over the surface of the soil and make any chemical adjustment as recommended by a soil test, then till Compost into the top 6 inches of the soil (see 3.2).

 

3.6 Soil in the Root Zone of Established Trees

▶ Condition to be modified: Surface compaction near or above root limited levels in the upper soil horizon the result of traffic or other mechanical compaction.

▶ How to modify this condition: Remove the tops of all plants to be removed from the root zone. Remove sod with a walk behind sod cutter. Do not grub out the roots of the plants to be removed. Loosen the top 9–12 inches of the soil and mix in Compost. Surface roots may move and separate from the soil during this process, but the bark on roots should not be broken.