Grapevine Water Management
Vineyard Irrigation Systems
Irrigation systems are a significant investment; systems should be carefully planned and designed. Factors such as soil type, soil depth, the effective rooting zone of the vines, vine density, water quality, land formation, and economic factors, including capital and operating costs, will all play a role in determining the irrigation system. Irrigation systems should encourage vine growth while minimizing soil erosion and water loss. Losses of water will occur due to evaporation, wind drift, runoff, and water (and nutrients) sinking deep below the root zone. Irrigation systems for grapevines can be categorized into several types. Overhead sprinkler systems spray water into the air above the vines in a broadcast pattern. Flood or furrow irrigation systems that use gravity to distribute surface water to precision-graded vineyards. Under-the-vine irrigation systems are with drip or micro sprinkler. No single irrigation system is the solution for all vineyard situations; otherwise, there would not be such a range of systems still available. An overview of irrigation system options for vineyards is provided below.
Overhead Sprinkler Irrigation
Overhead sprinkler irrigation is an irrigation system in which water is distributed throughout the vineyard by the aid of high-pressure overhead sprinklers mounted on high permanent standpipes that clear the tops of vines (Figure 11.3). The sprinklers are placed in a regular pattern over the vineyard. All of the sprinklers can be operated simultaneously, or the vines can be irrigated in zones (alternatively, irrigating groups of sprinklers connected by common laterals).
Microirrigation
Microirrigation is a method of providing water directly to the root zone of plants, minimizing water loss and improving efficiency. Microirrigation systems can apply water on a short-set, high-frequency basis, optimal for younger vines with a smaller root mass, or on a long-set, lower-frequency basis to provide a more consistent, optimal soil moisture environment for mature vines, depending on your particular vineyard and water supply situation. Microirrigation typically includes two main subcategories:
Drip Irrigation
Drip irrigation, also known as trickle irrigation, involves dripping water onto the soil at very low rates through a system of small-diameter plastic pipes fitted with outlets called emitters or drippers (Figure 11.4). Drip emitters come in two basic configurations: compensating and non-compensating. Compensating emitters provide nearly the same discharge rate over a wide range of operating pressures. Non-compensating emitters will have a change of discharge rate corresponding with a change of operating pressures. Where vineyards are relatively flat, a properly designed irrigation system will provide high water application uniformity using non-compensating emitters. While pressure-compensating emitters will also offer good uniformity on flat ground, their application is most advantageous in changing topography or with extended tubing lengths.
Micro-Sprinkler Irrigation
Micro-sprinkler irrigation systems are very similar to drip irrigation systems except that, rather than discharging water at discrete points, the water is sprayed out through a small sprinkler device (Figure 11.5). These micro-sprinklers are typically made of plastic and are available in a multitude of flow rates and spray patterns. Like drip irrigation systems, micro-sprinkler heads operate with low water pressure and use small-diameter pipes.
Furrow Irrigation
Finally, with furrow irrigation, water is diverted from a main ditch generally into a channel running on either side of each row, or sometimes into a single central channel (Figure 11.6). Furrow irrigation generally requires the lowest capital investment, but can require significant manual labor for effective management.
Click on the following topics for more information on grapevine water requirements.
