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<br />Appendix C. Soil Preparation Guidelines
<br />
<br />Although not a visible component of landscape in-
<br />stallation, soil preparation is the key to the long
<br />term success of an entire project, Soil preparation
<br />becomes even more important when trying to maxi-
<br />mize water conservation, Water that Is lost through
<br />run-off, evaporation from standing puddles, or
<br />can' be absorbed from water-logged oxygen-poor
<br />soil is of no benefit to the plant material. Soil prep-
<br />aration can insure long term plant survival and ac-
<br />celerate plant maturation, Increasing soil water ab-
<br />sorption capacity and creating an environment that
<br />encourages root growth provides a critical extra
<br />advantage tor any newly installed landscape,
<br />
<br />Unlike natural, undisturbed soils, the soils along
<br />the 1-25 corridor have been continuously compact-
<br />ed and altered through highway construction pro-
<br />jects, resulting in a combination of soil problems
<br />within any given area that require correction before
<br />plant material is installed, Some 01 the more com-
<br />mon soil problems might be; layering of different
<br />types of soils, top soil and subsoil compaction,
<br />construction debris used in the fill material, low nu-
<br />trient levels, contamination, etc,
<br />
<br />Guidelines:
<br />
<br />. All soil preparation must be completed before
<br />an irrigation system or plant material is in-
<br />stalled,
<br />. Remove all man made debris from the surface,
<br />including concrete and asphah,
<br />. A soil analysis is recommended for each project
<br />sile, with samples from several different loca-
<br />tions, to determine needed amendments. Soil
<br />amendments must be included in soil prepara-
<br />tion before planting. The heavy clay soil typical
<br />of this area has a low oxygen carrying capacity,
<br />making soil amendments to Improve soli struc-
<br />ture and oxygen capacity a must for long term
<br />plant survival,
<br />
<br />. Check for any buried utilities that might be en-
<br />countered and make provisions to protect
<br />them,
<br />. Rough grade to approximately four inches below
<br />linal desired grade,
<br />. Do not work soils when they are wet unless it is
<br />absolutely necessary, this includes the instal-
<br />lation of sprinkler systems and plant material.
<br />. In lieu of a soil sample, apply 40 Ibs, 01 triple su-
<br />perphosphate per 1,000 sq, It, or 10 Ibs. diam-
<br />monium phosphate and 30 Ibs of triple super-
<br />phosphate per 1,000 sq, It_ by proadcasting.
<br />Phosphates must be tilled Into the soil. Also
<br />apply a high quality, ground organic matter
<br />(75% or more organic maller, low in soluble
<br />salts) at the rate 01 3 cu, yds, per 1,000 sq, fl.
<br />. Uniformly apply 4 inches of screened topsoil
<br />( 113 01 which should be course sand) over the
<br />entire area.
<br />. Scarify all ot the project area wilh a single tooth
<br />ripper before planting and after heavy equip-
<br />ment has been on the sile. Rip the soif no less
<br />than 18 to 24 inches deep, 18 inches apart.
<br />Ripping should be done across the slope rather
<br />than down the slope to reduce the chances 01
<br />erosion, On relatively ffat ground ripping can
<br />be acomplished in both directions,
<br />. Remove all man made debris, and other objects
<br />that might hamper further soif preparation,
<br />planting, and maintenance,
<br />. Rototill to blend the amendments into the top
<br />four to six inches, Avoid excessive working of
<br />the soil, especially if a clay soil is involved,
<br />. Bring to a final grade before installation 01 irriga-
<br />tion and landscape material.
<br />
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<br />48.
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