A subsurface system is flexible and can provide frequent light irrigations. This is especially suitable for arid, semi-arid, hot, and windy areas with limited water supply, especially on sandy type soils.
Favorable conditions for the most effective operation of subirrigation are an impermeable subsoil at a depth of about 4– 6 ft, a highly permeable loam, sand, or sandy loam sur- face soil, and a relatively uniform field slope.
Subsurface drip irrigation is mainstream method in California. Subsurface drip irrigation is principal method for irrigation of tomatoes. Subsurface drip irrigation is alternative irrigation method for some tree crops.
Many growers report more uniform plant growth and less foliar disease with subirrigation. The increase in plant uniformity may be the result of more even and complete moistening of the growth medium and better distribution of nutrients absorbed by capillary flow.
Similarly, there are circumstances and situations that present disadvantages to selection of an SDI system. These disadvantages also may be subdivided along the lines of water and soil issues, cropping and cultural practices, and system infrastructure issues.
Subsurface irrigation is a method of delivering water directly to the root zone of crops by placing a dripline below the soil surface. This technique is becoming increasingly popular due to its high efficiency in water and nutrient management, which ultimately leads to improved crop yields and quality.
Irrigation helps to grow crops, maintain landscapes, and revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation is also employed to protect crops from frost, suppress weed growth in grain fields, and prevent soil consolidation.
Issues associated with surface irrigation
Waterlogging - Can cause the plant to shut down delaying further growth until sufficient water drains from the rootzone. Waterlogging may be counteracted by drainage, tile drainage or watertable control by another form of subsurface drainage.
There fore, an SDI system can deliver water with an efficiency of 95 percent or higher. This means that for every inch of water that is pumped, 0.95 inch or more stays in the crop root zone, where it is needed.
Water Efficiency: Drip irrigation systems excel at water conservation, as they deliver water directly to the root zones with minimal waste due to evaporation or runoff. Studies have shown that drip irrigation systems can save up to 70% more water compared to traditional sprinklers.
Subsurface drip irrigation systems deliver low flow rates of water very uniformly. A properly designed and maintained system should last more than 20 years. A maintenance program includes cleaning the filters, flushing the lines, adding chlo- rine, and injecting acids.
Subirrigation is used in growing field crops such as tomatoes, peppers, and sugar cane in areas with high water tables such as Florida and in commercial greenhouse operations.
Each surface system has unique advantages and disadvantages depending on such factors as were listed earlier like: (1) initial cost; (2) size and shape of fields; (3) soil characteristics; (4) nature and availability of the water supply; (5) climate; (6) cropping patterns; (7) social preferences and structures; (8) ...
Drip irrigation is the most water-efficient way to irrigate many different plantings. It is an ideal way to water in clay soils because the water is applied slowly, allowing the soil to absorb the water and avoid runoff.
Irrigated areas are further divided into irrigated wet season when rainfall is supplemental with irrigation water and irrigated dry season when rainfall is very low and irrigation is the primary source of water supply.
However, soak pits ar covered pit like structures that helps drain runoff water into ground. They are not used to irrigate farmlands.
(1) Permanent subsurface drip installation requires less yearly labor than surface drip installation and increases the life expectancy of the system; (2) Cropping with a dry soil surface has the potential to reduce the occurrence of soil borne diseases and help control weed infestation; (3) Dry soil in the furrows ...
The burial is generally 10 – 30 cm (4 – 12”) with thicker drip line/tape (minimum 12 mil and up to 45 mil) used to ensure that the product will properly function for many years.
Disadvantages of Sub-Irrigation
Uniformity is key for successful sub-irrigation. Areas of a field that are sloped or have different types of soil will affect the permeability and capillary rising of water and may cause the water table to rise either too high or not high enough for effective sub-irrigation.
Subsurface drip irrigation is a low-pressure, high efficiency irrigation system that uses buried drip tubes or drip tape to meet crop water needs. Subsurface irrigation saves water and improves yields by eliminating surface water evaporation and reducing the incidence of weeds and disease.
In arid regions, the advantage is mainly to minimize the buildup of excess salinity in the crop root zone. A disadvantage of subsurface drainage is that its often more costly to implement per unit area compared to surface drainage, especially for fine textured soils.