Vineyards has long since known the effects of the harsh summer on their vines. The question arises though, how did they make grapes grow with the harsh summers. During the summer month's temperature can reach as high as 105 degrees Fahrenheit, enough to boil the juices within the grapes. This high temperature combined with a lack of rain for several days at a time will dry out the soil thus leaving the vine to starve for nutrients. To combat the drought, please see our recommendation for drip irrigation systems, which will provide the vines with a constant watering and additional option of injecting fertilizer.
Drip Irrigation in grape vine
Drip irrigation installation in grape vine use a wire for support and a drip hose as a supply line that feeds the drip emitter. The drip emitter we recommend is a .5 or 1 GPH pressure compensating barbed dripper that lets a .5 or 1 GPH to flow in a range of pressure between 7 to 45 PSI. The water is drips out of the drip emitters, and provides a microclimate and a deep watering.
Many types of soils are used for growing grapes, but they are most successfully grown on sandy or fine sandy loams with average fertility and good drainage. On soils low in fertility, grapes grow slowly and produce low yields; on extremely fertile soils, vines usually grow excessively and the crop matures late. Fine, tight soils that contain much clay are not suitable for grape production. Regardless of soil type, the drainage must be good. Impervious layers of clay closer than 5 feet to the surface may cause poor drainage and salt accumulation.
Unless drip irrigation is to be used, the land for a vineyard should be leveled and disked before plants are set. Grapes vine used with drip system are planted 6 to 8 feet apart in the row and rows are separated 8 to 12 feet
The distance between rows depends on the trellis used. In commercial vineyards, adequate space must be provided for roads at the ends and sides of the vineyard and for driveways through the center of the planting to give ready access for harvesting and cultural operations. Twenty to 25 to 30' feet is generally adequate for driveways.
Set a post 2 x 2 inches or larger beside the vine. The post should be 30 to 36 inches above the ground. If the selected cane seems weak, cut it back to two buds in the second spring, if it is vigorous, do not cut it back. Tie the cane and the future shoot that is to form the trunk to the post. Remove all lateral shoots. When the shoot is within 6 inches of the top of the post, cut off the terminal to encourage laterals to form the head.
The amount of water and frequency of application necessary to meet the needs of grapevines grown in different soil types vary considerably. Available soil moisture must always be present in the root zone during the growing season, especially when the most rapid growth of the berries occurs. Young vines must be watered more frequently than older vines, particularly during the first year. Bearing vines grow rapidly in spring and early summer, putting on a succulent type of growth. Normally, a gradual slowing of shoot growth occurs as the berries enlarge. Growth rate continues to slow and almost stops as the fruit begins to ripen.
A shortage of available soil moisture greatly reduces the normal growth rate of a grapevine. A further reduction in moisture supply may be detected by the appearance of a soft, yellowish green color in the terminal leaves. Grapevines are quite tolerant to drought, but when heavily stressed, the soft-green color at the terminals turns to gray-green, and plant growth almost stops.
Grapes grown on medium to heavy soils normally require 20 to 30 inches (51-76 cm) of irrigation water per season. In lighter sandy soils, 3 to 4 feet (91-122 cm) of water may be needed to produce satisfactory crops and to provide for normal growth. Drip irrigation, used in vineyards, will help achieve efficient water use.
The grape is a deep-rooted plant; therefore, apply a heavy irrigation in winter and in early spring just before growth starts, to wet the soil to a depth of 6 to 8 feet (1.8-2.4 m). The young developing shoots, leaves, and fruit require little additional water during April and May. As the leaf area increases and the berries begin to enlarge, maintain available moisture throughout the root zone.
Drip Irrigation Must Apply Water Uniformly to be Efficient
In order to be efficient, a drip system must apply water uniformly throughout the vineyard. This is accomplished by having little variation in flow rate among drippers (high emission uniformity is available with a PC dripper). Dripper plugging and uneven pressure distribution are the major factors contributing to system inefficiencies. The emission uniformity of a drip system can easily be measured. It is used to evaluate system design and maintenance. Emission uniformity should be considered when scheduling irrigations. A stopwatch, measuring cup, pressure gauge with attachments, and a little time is all that is needed to evaluate a drip system. The flow rate from at least 20 drippers should be measured from various locations in the system. Check drippers at the beginning and end of hoses and select hoses from the high pressure and low-pressure end of the underground manifold. One minute is all the time needed to measure the flow from a dripper? Dripper flow rates can then be expressed as gallons per hour.
Pressure distribution is evaluated by measuring pressure at the first and last drip line inlets on several manifolds as well as the high and low pressure end of hoses. Also, note the pressure at the pump and pressure loss across the main filter.
To determine the emission uniformity of a drip system, divide the average discharge of emitters with the lowest 25% flow rates by the average flow rates of all emitters. For example, after measuring the flow of 20 drippers, it was found that the average flow rate of all drippers was 1 gallon per hour; whereas, the average flow from the five with the lowest discharge was 0.8 gallons per hour. The calculated emission uniformity in this example is 80% (0.8 divided by 1).
Grading of emission uniformity is given in the table. A system with an emission uniformity of 90% or greater is operating efficiently; therefore, if irrigations are scheduled properly, irrigation efficiency will be high. When emission uniformity drops, the ability to irrigate efficiently also drops. For example, an emission uniformity of 50% would require over irrigating (2X) satisfying water requirements of vines that have drippers with low discharge. This can reduce yields, wastewater, and energy. It is a no-win situation, and the only solution is to improve the emission uniformity of the drip system.
Drip systems should be evaluated once a year. An effective evaluation will detect poor performance and then pinpoint the problem. Remember to document operation pressure when measuring emitter flows; otherwise, valid comparisons with past and future evaluations will be difficult (dripper flow rates change with pressure). It is a good policy to evaluate a newly installed drip system to establish a baseline for future evaluations.
The majority of the systems we have tested were operating with an emission uniformity of 80% or greater. Systems with poor emission uniformity had drippers that were plugged or problems with pressure regulation.
When plugging is a problem, the variation in dripper flow rates tends to be randomly distributed throughout the vineyard. However, when pressure regulation is the culprit, drippers with low flow rates are located at the ends of hoses (excessive drip line length) or at the low-pressure end of the manifold (manifold pipe too small).
In our system evaluations, high emission uniformity was evident in systems that were maintained properly, which includes servicing filters, flushing drip hoses, and using appropriate chemical treatments. In a very few instances, poor system design was the culprit, requiring major changes in underground pipe or drip lines to improve emission uniformity.
Drip systems having well to excellent emission uniformity indicate that water and injected fertilizer are distributed evenly throughout the vineyard.
Emission Uniformity Rating
90 - 100% Excellent
80 - 90% Good
70 - 80% Fair
Less than 70% Poor
Question and answer
When is the best time to water?
Drip irrigation systems provide your plants with the slow, deep, uniform supply of water they need, encouraging the growth of roots and enabling the plant to seek out water at different levels in the soil. Water in the morning, when humidity is high and temperature is low. Allow the soil to dry slightly between watering. This enables air to mix with the soil particles and aid in plant growth. For the backyard grower we recommend watering three times a week for 8 - 10 hours at a time. If you have had a lot of rainfall, this would be decreased.
What are some tips on ensuring the most efficient water saving action?
Emitters keep getting clogged with dirt. What can I do?
If your emitters clog often, it may be a sign there is dirt in your water supply. In that case, you might want to consider adding a filter to keep out debris.
Design criteria for grape vines