Apparatus for and method of irrigating soil

Abstract

In a apparatus for irrigating soil for cultivating plants, a water supply pipe is buried in soil, plural porous pipes being connected to in a conduit while disposed at proper positions of the conduit in the water supply pipe, fine pores being provided in a wall surface of the porous pipe, the fine pores being not provided in a wall surface of the conduit that is able to pass water; both ends of the water supply pipe are connected to a water tank at positions lower than the porous pipe; a water surface of the water tank is usually maintained at a level horizontally equal to or lower than the porous pipe; the water supply pipe is saturated with water from the water tank; water is intermittently supplied to the water tank; and a position of the water surface in the water tank is set slightly higher than positions of the porous pipes buried in the soil, and a water partial pressure of the water tank is set to a slightly positive pressure.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]Conventionally, there have been proposed many methods for irrigating soil in which plants are cultivated. One of the methods is a water-saving irrigation method proposed by B. E. Livingston in 1934. A principle of the water-saving irrigation method is a method for irrigating the soil by utilizing a water pressure difference. In the water-saving irrigation method, a porous pipe is buried in the soil in which the plants are to be cultivated, the porous pipe is saturated with water, the soil is irrigated when the soil has a low water partial pressure, and excess fluid is taken in (drawn into) the porous pipe when the soil has a high water partial pressure. One of the features of this water-saving irrigation method is that a small amount of water is used.[0003]2. Description of Related Art[0004]Japanese Laid-open (Kokai) Patent Applications Publications Nos. 9-9802 and 9-308396 propose techniques as examples of practical us...

AI Technical Summary

Benefits of technology

"The present invention solves the problem of being able to stably irrigate soil even when there are rapid changes in external environment such as temperature, humidity, and plant growth. The invention includes a water supply pipe with multiple porous pipes and a conduit, and a water tank connected to the pipe. The water tank is maintained at a level lower than the porous pipes, and water is intermittently supplied to the tank to maintain a positive pressure. The invention allows for stable and continuous irrigation of soil even when there are rapid changes in external environment. It is simple to operate and eliminates the risk of excess irrigation."

Problems solved by technology

According to the techniques proposed therein, gases such as air dissolved in water in a water supply system (or a water transporting system) including the porous pipe and a conduit may come out of solution as bubbles due to changes in environment such as changes in temperature, and occasionally, the bubbles adhere to an inner surface of the porous pipe and block fine pores, which results in a problem in that liquid cannot be supplied to the soil even if a pressure difference exists between the inside and the outside of the porous pipe.

Therefore, when the soil that is in contact with the surface of the porous pipe peels off from the surface of the porous pipe, the soil cannot be irrigated by utilizing the water pressure difference.

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