Saturday, January 31, 2009

Turf and Landscape - Compaction

Soil compaction is one of the major problems affecting plant growth in turf and landscape areas. Soils are compacted by equipment traffic during construction, equipment and vehicle traffic over top of areas in existing landscapes, foot traffic, soil movement, tilling soils when they are too wet, and mishandling soils. The following are some of the consequences of compaction.

•Compaction destroys soil structure; increases soil bulk density; increases small pore space, decreases large pore space. This will reduce plant rooting because fine roots cannot grow into compacted soils.
•Compaction contributes to lower air porosity, lack of soil aeration; increases carbon dioxide in soil; and decreases oxygen diffusion. Again, this reduces plant rooting by reducing the ability of plant roots to respire and therefore grow.
•Compaction contributes to reduced water infiltration and percolation; increases surface water runoff; increases water evaporative losses; decreases drought hardiness; and increases need for irrigation. Compaction will reduce water entering in soils and reduce rooting of plants thus causing more water stress.
•Compaction causes greater soil temperature extremes; Increases heat conductivity and canopy temperatures of turf.
•Compaction decreases nutrient uptake; decreases nitrogen use efficiency; and increases need for fertilization. By limiting rooting, plants have reduced soil area to extract mineral nutrients from.
•Compaction decreases soil applied pesticide effectiveness; increases weed pressure by compaction tolerant weeds, increases need for herbicides, and increases the need for fungicides to control soil borne diseases.
•Compaction limits rooting, decreases plants’ stored food reserves, and increases plant susceptibility to wilt and disease.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

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