System and method for irrigation

A method for subsurface irrigation of plants or seeds comprising the steps of;

• i. providing one or more porous uncoated tubes into which an aqueous irrigation fluid is supplied to one or more of the tubes, wherein the tubes are in fluid contact with each other and comprise materials having a hydrostatic pressure head (HH);
• ii. passing a sufficient quantity of aqueous irrigation liquid into the tubes at an applied pressure Pgermination during germination of the seeds;
• iii. allowing the germinated seeds to enter a growth phase;
• iv. passing an aqueous irrigation liquid into the tubes during said growth phase of the plants to be irrigated, at an applied pressure (Pinitial) for a time T1;
• and
• v. lowering the head pressure of said aqueous irrigation liquid in the tubes during said growth phase of the plants to be irrigated, to an applied pressure (Pgrowth) that is at or below HH;
• wherein applied pressure Pgermination is 10% or greater more than HH, and Pinitial is equal to or greater than Pgrowth and wherein the tubes are configured such that the aqueous irrigation fluid enters the tube configuration and is pressurized therein such that the minimum length of tubing between the irrigation fluid entry point and at least one of the plants to be watered is 61 meters and wherein the HH of at least a portion of the one or more tubes is at least 100 cmwc and wherein, once filled with fluid, the tubes will remain filled when the applied pressure is removed.

A system for use in subsurface irrigation of plants comprising;

• i. one or more porous tubes that are not coated with a hydrophilic material and that are arranged in a configuration, wherein the one or more tubes each have an enclosing wall and an interior space contained thereby such that the tubes' interior spaces are in fluid contact, and one or more of the enclosing walls comprise sections that have a hydrohead (HH) equal to or greater than 100 cmwc,
• ii. an exterior region that is a continuous space that is exterior to the tubes and contains a growth medium for plants,
• iii. aqueous irrigation fluid located in the interior space of the one or more of the tubes and held at an applied pressure (Pgrowth),
• iv. a plurality of plants that are in their growth phase and whose roots are located in the exterior region,
• v. an irrigation fluid entry point where aqueous irrigation fluid may enter the interior space of the tubes,
• wherein the tubes are located with at least a portion of the length of at least one tube in the proximity of a plurality of roots of plants to be irrigated, and the irrigation fluid entry point is located such that the minimum length of tubing between the irrigation fluid entry point and at least one of the plants to be watered is 61 meters and, wherein once filled with fluid, the tubes will remain filled when the applied pressure is removed.