The amount of water available to your vines throughout their growth period will largely contribute to how much yield you get and the quality of the fruit. Unfortunately, total dependence on rainfall doesn’t cut it, so growers and vineyard owners use different irrigation systems to supply more water to the vines.
However, no matter the irrigation system you use, you’ll have to ensure that there is good water distribution uniformity throughout the vineyard. Nevertheless, it will help you conserve water and avoid the possible scenario of under or overwatering some plants.
How to Improve Water Distribution Uniformity in a Drip System
Drip irrigation is best preferred among vineyard owners because of its ability to water the plants slowly and maintain moisture at an optimal range. It involves placing lines with emitters alongside the plants such that the emitters release water drops intermittently around the root zone.
When a drip irrigation system is new, the Distribution Uniformity (DU) percentage is above 90%, and the performance is excellent. Over time, the system’s DU begins to decline for reasons such as:
- Worn out emitters
- Maladjustment of the system’s pressure
- Deterioration of other physical components of the system
- Clogging of the tubing and emitters
A low DU percentage can lead to:
- Insufficient nutrient delivery to the vines.
- Poor crop quality.
- Overworked pumps.
- Increased labor expenses to replace emitters.
- Over and under irrigation.
- Poor yields.
Regular maintenance of the system will help keep the DU high. Here are some tips to improve the water distribution uniformity in your vineyard.
1. Use adjustable pressure regulators
Pressure regulators are installed at different points in the field and the pump stations to help regulate the pressure as per the water demand. The initial pressure may vary depending on the farm’s land topography and water requirements.
However, using adjustable pressure regulators will allow for adjustments that match the requirements of the field. These regulators should undergo routine maintenance checks where they are serviced and cleaned.
2. Flush irrigation lines frequently
As water passes through the lines over time, they form clogs as a result of bacteria and chemical buildup. Therefore, leaving the lines unattended for a long time might slow down water distribution in some parts of the field and increase pressure in others.
Proper flushing of the drip irrigation system often will help keep the irrigation lines clean and push pollutants out of the system. If you are wondering how long you should flush a drip irrigation system, here’s a flushing time calculation to help you.
Flushing time (minutes) = (Length of pipe (meters) / Flow rate (m/sec)) X 60 Flow rate (m/sec)
You can choose to flush a few hoses at a time to increase the flow rate at the pump. An increased flow rate breaks down the sediments accumulated on the walls of the hose and forces them out. The recommended flushing flow rate for the main and sub-main lines is 1.5 m/sec, and that of drip lines is 0.5 m/sec.
At the beginning of your flushing exercise, the water may be colored due to the dirt coming out with it, but the water clears up after some time. Clearing the water indicates that the pipes are clean.
3. Invest in a smart irrigation system
A smart irrigation system can help you maintain a high DU percentage in a few ways.
For starters, it ensures that you get alerted to irregularities in your lines, such as leaks and clogs, to help you proactively perform any required maintenance like flushing lines, as mentioned above.
It also gives you the ability to easily irrigate with precision through automated scheduling of blocks, sub-blocks, or rows. This is something that wouldn’t be feasible with a traditional system, due to the high level of oversight that would be required by the grower to constantly adjust settings manually.
Perhaps most importantly, as smart irrigation systems help improve DU, they do so in a way that minimizes the amount of water needed throughout the entire vineyard, since only rows requiring water receive it, as opposed to watering an entire block..
4. Change the types of filters used
If the filters used at the pump station do not match the irrigation system you are using in your fields, you may end up wasting so much water, failing to achieve good water distribution uniformity. Therefore, the type of irrigation water you are using will also play a part in determining the type of filter you use.
For example, if you are using sandy or dirty irrigation water, a disc filter may not do the job. Such water calls for a media filter because it is designed to remove such organic material from the water. However, if you are using clean irrigation water, you can use a tubular screen filter that can automatically clean itself through a backflush.
Changing the type of filters you are using and checking them regularly for maintenance will help you improve the irrigation distribution uniformity in your vineyard.
5. Routine system maintenance
It’s important to start evaluating the performance of your irrigation system immediately after installation and record it. Perform regular tests on the pump, check emission flow rates, and adjust the pressure while observing the changes in its performance in the field.
As part of routine maintenance, ensure that you inspect the filters for possible corrosion, clogging, and other signs of degradation over time. In addition, check backflush systems, clean them, and regularly treat the water to clean micro-organisms that can cause bacteria buildup.
These practices allow you to improve irrigation efficiency as well as track maintenance costs. In addition, it will help you know when it’s time to modify the system, upgrade it, or replace it.
Bottom Line on Getting Better Water Distribution Uniformity
It’s expected for the Distribution Uniformity (DU) to degrade over time, but it’s up to you to ensure that it remains as high as possible through proper maintenance practices. An automated irrigation system can make this easier, as you’ll know when and where you need to perform maintenance, before the system breaks down.