Section 1     Subsoil Preparation

1.1 General

The specifications of Section 1 shall apply only to sites where topsoil is to be deposited over existing or disturbed subsoil in preparation for turfgrass seeding; seed shall not be placed in subsoil. All labor, equipment, and materials required for the completion of Section 1 shall be furnished by the seeding contractor, unless specified otherwise.

1.2 Subsoil Definition

Subsoil shall be defined as any or all of the natural soil layers of the seeding site, or any soil which meets the specifications of Section 1.2, or any soil of a composition and/or depth which may be otherwise specified and approved by all affected parties. Subsoil shall contain a maximum volume of 25% of rock, stone, or other materials larger than 0.10 inches in diameter, and shall contain no rocks, stones, or other materials larger than 5.0 inches in diameter. The depth of the subsoil layer, i.e., the thickness of the layer of subsoil which lies upon rock or other material which does not itself constitute subsoil, shall be a minimum of 6.0 inches deep. When the subsoil layer is less than 6.0 inches deep, either topsoil or subsoil shall be moved to the seeding site and deposited in a layer over the subsoil of the seeding site so that the base upon which the final topsoil layer is deposited (see Section 2) is at least 6.0 inches deep. Subsoil shall not contain any chemicals or other materials in concentrations which may be toxic to the growth of turfgrass or other seedlings.

1.3 Subsoil Testing and Physical Properties

1.3a Subsoil Testing Requirements

Subsoil shall be tested by The University of Maryland Soil Testing Laboratory, or another accredited soil test lab for soil acidity (pH), soluble salts concentration, phosphorus (P or P2O5), and potassium (K or K2O). If, because of contractual obligations or other compelling reasons, there is insufficient time to conduct and evaluate subsoil test results before topsoil is deposited and spread, a subsoil sample shall be collected before topsoil is deposited, and subsoil tests shall be conducted and evaluated as soon as possible thereafter. All parties which may be affected by subsoil conditions that may adversely influence the success of turfgrass seedings shall be promptly notified by the seeding contractor of the results of such soil tests.

1.3b Subsoil Acidity (pH)

Subsoil shall be tested for soil acidity (pH). The pH of the subsoil, to a depth of 4.0 inches, shall be suitable for the addition of topsoil when the subsoil pH lies in the range of pH 5.5 to pH 7.5. Subsoil with pH 6.5 is ideal. When subsoil pH is not within pH 5.5 to pH 7.5, modifications to correct subsoil pH shall be made according to the recommendations of the soil test lab, or of the Maryland Cooperative Extension Service, or by using Table A or B, below, as follows: When subsoil pH is below pH 5.5, see Table A, and add the amount of limestone recommended to raise subsoil pH to pH 5.5 to pH 7.5. When subsoil pH is above pH 7.5, see Table B, and add the amount of elemental sulfur recommended to lower the subsoil pH to pH 5.5 to pH 7.5. Except as allowed in Section 1.2a for contractual obligations or other compelling reasons, topsoil shall not be deposited or spread over subsoil with a pH below pH 5.5 or above pH 7.5. See Section 4 for information about limestone and elemental sulfur.

Table A
Pounds of Limestone to Add per 1000 ft2
To Raise Soil pH to 6.5

Soil Texture Class

Original pH  Sand  Loam Clay
4.8 85 140 200
5.0 75  125 175
5.2 65 110 150
5.4 55 95 125
5.6 45 80 100
5.8 35 65 80
6.0 25 50 60
6.2 15 35 40
6.4 5 15 20


Note: Table A shall be used only for limestone which meets the specifications Section 4.3

 

Table B
Pounds of Elemental Sulfur to Add per 1000 ft2
To Reduce Soil pH to 6.5

Soil Texture

Original pH Sandy Soil  Clay Soil
7.5 10-15 20-25
8.0 25-35 35-50
8.5 35-50 40-50


Note: Table B shall be used only for elemental sulfur which meets the specifications of Section 4.4

 

1.3c Subsoil Soluble Salts

Subsoil shall be tested for soluble salts concentration. Soluble salts present in the subsoil shall not exceed 500 parts per million (ppm) by weight or 4.0 millisiemens per centimeter (ms/cm) when evaluated by the electrical conductivity method. Modifications to reduce subsoil soluble salts concentrations shall be made according to the recommendations of the soil test lab, or of the Maryland Cooperative Extension Service, or by using Table C, below, as follows: When subsoil soluble salts exceed 500 ppm or 4.0 ms/cm, add the amount of gypsum recommended in Table C to reduce subsoil soluble salts concentrations below 500 ppm or 4.0 ms/cm. Except as allowed in Section 1.3a for contractual obligations or other compelling reasons, topsoil shall not be deposited or spread over subsoil with soluble salts concentration above 500 ppm or 4.0 ms/cm.

Table C
Pounds of Gypsum to Add per 1000 ft2
To Reduce Soluble Salts to Recommended Levels

Original Salts Level

 Pounds Gypsum

millisiemens  parts per million (ppm)  per 1000 ft2
8 2500 320
7 1800 230
6 1250 160
5 700 80
4.5

550

40


Note: Table C shall only be used for finely ground gypsum which meets the Specifications of Section 4.5

 

1.3d Subsoil Phosphorus and Potassium

Subsoil shall be tested for phosphorus (P or P205) and potassium (K or K20). Fertility recommendations for the site based on turfgrass requirements for phosphorus and potassium shall be obtained from the soil test lab or the Maryland Cooperative Extension Service. Subsoil levels of phosphorus and potassium shall be adjusted with fertilizer to conform with the recommendations of the soil test lab or the Maryland Cooperative Extension Service. Except as allowed in Section 1.2a for contractual obligations or other compelling reasons, topsoil shall not be deposited or spread over subsoil which is deficient in phosphorus or potassium.

1.4 Subsoil Grading

Subsoil areas which are intended to receive topsoil shall be maintained on a true and even grade, in compliance with architectural drawings and/or other applicable specifications pertaining to the site, with no significant depressions or elevations. Topsoil shall not be deposited or spread over the subsoil until rough grading has been completed and all areas within the subgrade are within 2/10 of 1.0 foot (equal to 2.5 inches per foot) from the final subgrade. If the graded area develops weed or other plant growth, the plants shall be eliminated before topsoil is deposited and spread over the subsoil.

1.5 Subsoil Tilling

After the subsoil has been graded, according to the specifications of Section 1.4, the surface of the subsoil shall be loosened by disking, tilling, or scarifying with rototillers, disk harrows, chisel plows, rippers, or other suitable soil preparation equipment. Where the slope of the seeding site is shallower than 3:1 slope, the surface of the subsoil shall be loosened to a minimum average depth of 2.0 inches. In sites where the slope is 3:1 or steeper, the subsoil shall be loosened to a depth of 0.5 to 1.0 inches. The surface of the subsoil shall be loosened immediately before topsoil is deposited and spread over site.

1.6 Site Protection and Damage Repair

1.6a Site Protection

It shall be the responsibility of the seeding contractor to install signs, flagging, etc. at the perimeter of the subsoil preparation site immediately after the completion of preparation operations, which shall serve to notify foot and vehicular traffic that a sensitive area may be damaged by their entry. The seeding contractor shall not be financially or otherwise held liable to repair a subsoil preparation site that is damaged by the entrance of such traffic when the site has been appropriately designated with signs, flagging, etc. at its perimeter (see Disclaimer, Section 1.9).

1.6b Erosion Protection and Damage Repair

.1. General. It shall be the responsibility of the seeding contractor to ensure that soil and other materials applied according to the specifications of Section 1 are not blown, washed, or otherwise removed from the subsoil preparation site, and so that nearby streams and other areas shall be protected from soil, fertilizer, compost, etc.

.2. Repairs to subsoil preparation sites. In the event of heavy rain, wind, or other natural event that causes damage to the subsoil preparation site which is of a kind or type that may have been anticipated or prevented by the seeding contractor, then the seeding contractor shall be obliged to make repairs limited to the damaged areas within the site, so that it is restored to a condition acceptable under the specifications of Section 1, and which may readily receive topsoil deposition according to the specifications of Section 2.

.3. Repairs to nearby areas. In the event of heavy rain, etc. that causes damage to the subsoil preparation site, as described in Section 1.6b.2., above, and which also causes damage to nearby areas, as may be evidenced by soil deposition on the surfaces of the nearby areas, etc., then the seeding contractor shall be obliged to make repairs to the damaged nearby areas, so that the nearby areas shall be restored to a condition substantially similar to their condition before the damaging event.

.4. Special limitations. The seeding contractor shall not be obliged, financially or otherwise, to regrade or make any other repairs to the subsoil preparation site, or to any nearby areas, when there is evidence that the damage caused to the site was substantially due to water, soil, or other materials which passed into the subsoil preparation site from an area which was not stabilized or under the control or supervision of the seeding contractor. Examples of situations which shall void the responsibility of the seeding contractor to repair the subsoil preparation site and nearby areas shall include the failure of responsible parties to provide effective groundcover, spillways, drainage diversions, water settlements, silt fence, etc. for areas which drain into the site, which would have prevented significant damage to the subsoil preparation site and nearby areas.

1.7 Clean Up

Grading stakes, stones, trash, and other debris which may hinder the distribution of topsoil, fertilizer, compost, limestone, etc., during topsoil preparation (Section 2), shall be removed when subsoil preparation operations are completed. Soil, fertilizer, compost, limestone, elemental sulfur, and gypsum shall be removed from paved areas as soon as possible after subsoil loosening operations are completed. Clean up operations shall be completed before acceptance is given.

1.8 Acceptance

1.8a Acceptance of Materials

The seeding contractor shall inform all affected parties of the composition of the fertilizer, compost, limestone, elemental sulfur, and gypsum which are intended for application at the subsoil preparation site before any of these materials are applied; acknowledgment of acceptance of these materials shall be given by the owner, general contractor, landscape architect, or other person(s) authorized to make such a decision before spreading operations are begun. Labels and other material identification pertaining to the materials which are applied shall be retained by the seeding contractor for a minimum of 90 days after the completion of spreading operations.

1.8b Acceptance of Performance

Acknowledgment of acceptable performance shall be given by the owner, general contractor, landscape architect, or other person(s) authorized to inspect the subsoil preparation site upon the satisfactory completion of each Subsection of Section 1. The subsoil preparation site shall be inspected within 24 hours of the completion of each Subsection, as indicated by the seeding contractor, unless specified otherwise. The seeding contractor shall give notification when all Subsections of Section 1 have been completed; final acceptance and payment shall be made within 24 hours of such notification, or within the time period specified in the contract.

1.9 Disclaimer

1.9a Damage

The seeding contractor shall not be financially or otherwise held liable to repair damages incurred to the subsoil preparation site as a result of materials not applied under the supervision of the seeding contractor, nor by vandalism, nor by acts of God. The seeding contractor shall not be financially or otherwise held liable to repair or otherwise amend the subsoil preparation site as a result of the use of topsoil, fertilizer, compost, or soil amendments which are labeled in error or which are otherwise not in accordance with the label or description provided with them by the manufacturer or distributor of the products, when they are applied by the seeding contractor in good faith, in accordance with their label or description.

1.9b Hazards

It shall be recognized that the subsoil preparation site is a construction zone not under the ownership or legal control of the seeding contractor, and as such may present hazards to persons or property which enter the site. The seeding contractor specifically disclaims any and all responsibility for the safety and security of persons or property which may enter the site before the seeding contractor has begun work or when work is underway or at any time after work has been completed, and without regard to whether such entry is legal or otherwise. The seeding contractor shall assume no responsibility for personal injury or property damage, nor be subject to any claims of negligence, when the seeding contractor has performed work according to the specifications of MSA-GS-99, as mutually agreed, or has applied products or materials according to the recommendations of their manufacturer or distributor.

1.10 Guarantee

1.10a General Guarantee

The seeding contractor shall guarantee that all materials and methods which are selected and used to prepare the subsoil of the seeding site under the supervision of the seeding contractor shall be appropriate for the site and the intended use of the site, and shall be selected and used according to the specifications of Section 1, unless specified otherwise.

1.10b Special Guarantees

.1. Subsoil composition. The seeding contractor shall guarantee that a subsoil layer of thickness and composition required according to the specifications of Section 1.2 shall be prepared and made ready for the addition of a final topsoil layer (Section 2) before the site is seeded.

.2. Subsoil acidity (pH). The seeding contractor shall guarantee that testing for subsoil acidity (pH) shall be performed as required according to the specifications of Section 1.3c, and that measures taken to modify, adjust, or correct subsoil pH shall actually obtain a subsoil pH required according to the specifications of Section 1.3b

.3. Subsoil soluble salts. The seeding contractor shall guarantee that testing for subsoil soluble salts shall be performed as required according to the specifications of Section 1.3a, and that measures taken to modify, adjust, or correct subsoil soluble salts concentration shall actually obtain a subsoil soluble salts concentration required according to the specifications of Section 1.3c., before topsoil is deposited. (Section 2).

1.11 Payment

The seeding contractor shall give notification upon the completion of Section 1; the work site shall be inspected within 24 hours of such notification, and payment shall be made at that time, or as specified in the contract. When payment is not received within the specified time period, the seeding contractor may void any guarantees related to Section 1, and may seek appropriate legal remedies.