The present invention generally relates to devices and systems for distributing water for the irrigation of cultivated plants. More specifically, the present invention is directed to an efficient irrigation device that limits evaporation, directs water to the roots of the plants, and controls weeds.
There are many different systems in use today for distributing water for the irrigation of cultivated plants, some of the systems being more effective and efficient than others. As water conservation increasingly becomes more important due to drought conditions and resulting city water use restrictions, there is a need for new devices and methods meant to very efficiently irrigate plants by not wasting water, but at the same time effectively providing the plants with enough water to keep them healthy.
A common method of watering plants is by hand. Conventional garden hoses or watering buckets are used for watering trees, shrubs, flowers, garden plants, etc. While this method delivers water directly to the plants, preventing water from being wasted where it is not needed, it is very time consuming and also wasteful in other ways. Irrigating plants in this way delivers water at a rate that is often too high to allow the soil and plant roots time to effectively absorb the water. Consequently, the resulting standing water is prone to evaporation or runoff.
Another common method of watering plants is by using sprinklers to simulate rainfall. While this method is effective for watering a large area of plants with little effort, it is also wasteful. Because the water is sprayed across the air in small droplets, it is more susceptible to evaporation, especially in dry climates. Also, the water droplets are not directed toward the roots of the plants where the water is most needed and much of the water is blocked from the roots by the plants' foliage or lands in areas where it is not needed. Even in a slightest breeze, much of the water from sprinkler systems is blown off target and wasted. This is known as wind drift.
To help solve these problems drip irrigation systems have been developed and have been considered to be the most desirable form of irrigation. Drip irrigation systems are desirable because they have been shown to save water, reduce labor, and are not as prone to evaporation or other environmental effects as are other irrigation systems. Drip irrigation systems are categorized as either line source or point source dissipation systems.
Line source dissipation systems, often referred to as soaker hose or drip tape, dispense water uniformly across the entire length of the water lines. This system is often used to water plants that are planted in line and close together. The soaker hose efficiently waters the plants by dispensing water in small amounts to the roots of the plants. This allows for the soil and roots to soak up the water minimizing evaporation and runoff. However, this system presents a problem when plants are spaced further apart because water is dispensed in unwanted areas.
Point source dissipation systems are designed to dispense water for plants that are spaced further apart and in scattered patterns. Water impermeable tubes extend from a main tube to the base of a plant where they have a dripper attached. This dripper drips water at the base of a plant when the system is turned on. This effectively waters plants that are spaced further apart without wasting water; however, other problems are presented with this system. Oftentimes water is not evenly distributed to the roots resulting in the root system of the plants not developing uniformly. Also, a standard drip emitter still releases more water than the plants need and consequently the water is wasted through runoff or evaporation. Pulsed and “Ultra Low Drip Irrigation” systems have been developed to solve this problem, but they require a great deal of maintenance as the drippers are easily clogged. These are also prone to damage and vandalism.
In addition to watering systems, the present invention relates to weed control or to mulch. There are various forms of mulch used in the home landscaping industry with additional types produced for commercial agriculture applications. The benefits of mulching include less water evaporation, less weeds, soil warming, and heat retention leading to earlier and higher yields, erosion control, and a more uniform appearance. Types of mulch include organic, plastic film, and irrigated mats.
Organic mulch, such as hardwood bark and pine needles, tend to be the most aesthetically pleasing, but organic mulch does have drawbacks. For example, it tends to quickly degrade in the environment, to wash away with heavy rains, or even to blow away with heavy winds.
Plastic mulch includes agricultural film, rings, and geotextiles. These are effective weed barriers and are preferred in most commercial applications where they can be placed prior to planting. They are very effective at preventing soil erosion and provide weed control while minimizing surface water evaporation. The perforated or woven versions, which are air and water permeable, are proving to be less desirable as weeds take root through the pores and cannot be removed.
To solve the problems presented by the drip systems and to combine the benefits of mulch with drip irrigation, mat watering systems have been developed. These systems provide for very little water waste as the water delivered to the plant is controlled by the mat, preventing over-watering. Also, since the mat is covering the dispensed water and the ground, water evaporation is not a problem. Since the mat is a form of mulch, it also acts as a weed controlling device as it prevents weeds from growing on the ground it covers.
One such mat watering system is disclosed in U.S. Pat. No. 6,997,402 to Kruer et al., which teaches a unitized mat of at least two polymeric material layers which are sized and shaped to cover an area immediately around at least one plant. The layers have an aperture for the plant to grow through and also an overlapping seam allowing the mat to completely cover the soil around the base of the plant. Fluid-conveying passageways are molded into at least one of these polymeric layers, which are meant to dispense and meter fluid into a root zone of the plant.
This mat system, however, has a number of disadvantages. The polymeric material layers that make up the mat are impervious to liquids and gases, which is not conducive to the overall health of the plant. For a plant to thrive, it needs the soil around its roots to contain a range of oxygen, nitrogen, and other gases that support the microbe environment of the soil. When an air impermeable mat is placed over the soil that blocks the passage of air to and from the soil, there is a risk that the microbe environment of the soil around the root system of the plant will not be supported and consequently, the plant will not thrive. This mat system also has the water-conveying passages molded into the layers, requiring a more complicated manufacturing process. For example, there have to be a number of different molds designed depending on the type of plant that will be watered by the mat. There also have to be different molds for the top layer and bottom layer of each type of mat. Additionally, when bonding the top layer to the bottom layer, extra care must also be taken to ensure that all of the areas are bound except for the water passageways.
Accordingly, there is a need for a device that provides the benefits of a typical mat watering system, but also is permeable to air to be conducive to soil and air gas exchange. There is also a need for a mat watering device that is inexpensive and simple to manufacture. The present invention fulfills these needs and provides other related advantages.