5 Soil Types That Affect The Use Of A Subsurface Drip Irrigation System

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Drip irrigation is an efficient way to keep your lawn or landscape looking its best, despite summer heat and drought. Subsurface irrigation equipment is buried in the soil so that moisture stays below ground to slow down evaporation and keep weed seeds from sprouting. Discover how the soil type on your property could interfere with the usual functioning of a buried irrigation system so you can make sure the installers adjust their approach properly.

Hard Pan

A hard pan is a layer of tightly compressed soil which forms due to drought, heavy weight over the surface, mechanical action through plowing, or a combination of all three. Layers of compacted soil affect how water flows after it leaves the irrigation emitter. While placing the drip lines over a hard pan can help move the water laterally by blocking downward flow, vertical layers will interrupt that flow. Burying a drip line under a layer of hard pan leads to a waste of water because the moisture can't rise to meet the plant roots. If you do deep plowing regularly to combat hard pan development, you're also likely to damage your buried irrigation equipment in the process.

Gradual Compaction

Aside from the compression that leads to hard pan, soil naturally compacts under weight and due to the presence of moisture. Soils with a fine texture with few coarse particles are known as non-bridging because they tend to slump and collapse more easily than soil with larger particles mixed in. Non-bridging soils are prone to compacting, especially when large equipment runs over the ground. This results in rising soil pressures that can crush single-walled and thin drip irrigation lines. The installers will need to use thicker walled and double-walled pipes if the soil is at risk for crushing the equipment over time. You don't want to dig up and replace the lines every year or so when you can get a few years out of them without disturbing the soil.

Loose Sandy

Soils with a high sand volume drain quickly and tend to lose water downward due to the lack of pressure between soil particles. This affects the efficiency of a drip irrigation system by reducing the lateral spread of water from each emitter. You'll have to use more emitters and place them closer to the surface in a subsurface irrigation system when working with a sandy and quick-draining soil, especially when you need to use the irrigation system to establish seeds for a lawn or delicate transplants. You may also need to place individual lines closer together to provide better coverage for large areas.

Cracking Clay

Heavy clay soils with little loam or sand also change how water flows when disbursed through an irrigation system buried under the surface. These soils tend to dry out dramatically and crack, and the resulting cracks allow water to flow to the surface for evaporation or drain directly to the subsoil without lingering around the roots. You may need to supplement with surface watering or techniques like mulching to prevent cracking so that water spreads out before traveling upwards or downwards and out of the root zone.

Mixed Rocks

Finally, consider the difficulty of excavating a landscape or field that has a heavy rock concentration before planning an extensive buried irrigation system. Not only is it more difficult to dig in general with rocky soil, but a solid layer of rock also limits the depth at which you can install irrigation equipment. Rocks also change the flow of water through the soil in unexpected ways. Consider a surface irrigation system instead to save time and energy on preparing the soil and removing large rocks.

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7 July 2016