- Author: Ben A Faber
Microirrigation systems include microsprinklers for tree crops, drip emitters for trees, vines, and some row crops, and drip tape for row and field crops. Microirrigation systems apply water to the soil through emitters that are installed along drip lines and contain very small flow passages. Microirrigation systems can apply water and fertilizers more uniformly than other irrigation methods. This uniformity results in potentially higher yields, higher revenue, and reduced irrigation operating costs.
Uniformity, a performance characteristic of irrigation systems, is a measure of the evenness of the applied water throughout the irrigation system. Distribution uniformity (DU), sometimes called emission uniformity (EU), is an index that describes how evenly or uniformly water is applied throughout the field. A uniformity of 100% means the same amount of water was applied everywhere. Unfortunately, all irrigation systems apply water at a uniformity of less than 100%, and thus some parts of a field receive more water than others. Field evaluations have shown that microirrigation systems have the potential for higher uniformity than other irrigation methods. However, clogging reduces the uniformity of applied water in microirrigation systems, thus increasing the relative differences in applied water throughout a field.
The small flow passages in the emitters and microsprinklers make microirrigation systems highly susceptible to clogging. Clogging reduces the uniformity of the applied water and decreases the amount of applied water. Clogging also decreases the amount of salt leaching around the lateral line in saline soils.
The objective of this web site is to provide information to irrigators about the causes of clogging and the methods for preventing or correcting clogging problems in microirrigation systems. Among the topics covered are the sources of clogging, chlorination, preventing chemical precipitation, filtration, flushing, and monitoring microirrigation systems.
This web site is divided into sections to allow the users to more quickly access the information they want. For example, if you already know you have a clogging problem and you want to solve it, go to the section Solutions to Existing Clogging Problems - "I have a problem and I want to solve it".
https://micromaintain.ucanr.edu/
![avocado irrigation 2 avocado irrigation 2](/blogs/blogcore/blogfiles/107783.jpg)
- Author: Lisa Nedlan UCCE Master Gardener
![A group of ollas A group of ollas](http://ucanr.edu/blogs/CoastalGardener/blogfiles/107595.png)
The effectiveness of olla irrigation lies in the interaction between soil moisture and the plant's roots. This dynamic creates a unique suction force, where the plant's roots 'pull' the water out of the olla if the soil is dry. Conversely, if the soil is wet from rainfall or surface watering, the water remains in the olla until the surrounding soil dries, ensuring a balanced and efficient watering system.
Implementing olla irrigation is not just about watering your plants; it's about fostering deep watering and dense root growth. This, in turn, enhances nutrient and water uptake, leading to healthier plants. Additionally, the controlled moisture levels prevent the extremes of wet and dry that can cause bitterness in greens and cracks in tomatoes and melons. As a bonus, the relatively dry soil surface acts as a natural deterrent to weeds and some unwanted insects, further enhancing the health of your garden.
Crops with fibrous root systems, such as tomatoes, squash, melons, and chiles, respond well to olla use. When using ollas with plants with shallow root systems, consider the shape and size of the olla and where the water will be in the soil. You can also use ollas with young perennial landscape plants (trees, vines, and shrubs.) Plants with woody roots might break an olla. If you notice that you are having to fill the pot more frequently, consider that a crack has formed in the olla.
Ollas are inefficient for densely planted annual crops due to the number of ollas necessary for even coverage.
Tips for using ollas
- Bury the olla, leaving 1 – 2 inches above the soil surface to keep dirt and mulch from getting inside. Gently pack the soil around the olla to prevent air pockets. Air pockets will prevent water from moving into the soil and keep roots from growing.
- To maximize impact, place ollas every 2 – 3 feet in the garden. Larger ollas, with a 2 or more-gallon capacity, can be placed up to 3 – 4 feet apart.
- If your soilis very deep, place a saucer or drainage tray under the olla at the bottom of the hole. This will promote water seepage outwards instead of downwards.
- Check the water level frequently and refill as necessary. Soil type, plant density, and weather can influence how often you need to refill. Refill times can vary from every seven days or more or as frequently as every other day.
- Cover the olla opening with a lid, rock, or plate to minimize evaporation and prevent mosquito breeding.
- Ollas are best suited for coarse-textured and/or sandy soil. Soil with a high clay content does not dissipate water well.
- When planting seeds, plant a few inches away from the olla opening. Water the entire planting area. If your olla isn't keeping the top 2 inches of soil moist, you may need to surface water until the seeds germinate.
- Know where your ollas are buried. Mark them with rocks, a pin flag, or something else to prevent someone from stepping on the olla.
- If you live in an area with hard freezes, dig up your olla each winter to prevent cracking underground.
Several types of ollas are available for purchase at garden shops, online, or from your local potter. There are several methods for making your own from clay or terracotta pots. Consider your space, the cost, how many ollas you will need, and how often you are willing to refill them. If you would like to make an olla from terracotta flower pots, click here.
![Tomato plant with olla in place Tomato plant with olla in place](http://ucanr.edu/blogs/CoastalGardener/blogfiles/107596.jpg)
Resources
How to use olla irrigation
https://wateruseitwisely.com/blog/olla-irrigation/
Olla Irrigation
https://images.nativeseeds.org/pdfs/Ollairrigationhandout.pdf
University of Arizona, Irrigating with Ollas
https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1911-2021.pdf
- Author: Elinor Teague
We need to deep irrigate more frequently than the previously recommended once a month and deep irrigation must begin at least one day before temps are predicted to be above 95 to 100 degrees for several days.
Check soil moisture levels underneath large landscape trees and deep irrigate whenever the top 5 to 6 inches of soil is dry. That could be several times a month from June to October. Younger trees and bushes planted within the last three years also may need several soakings a month. Soaker hoses are the most efficient and effective means of delivering deep slow irrigation at the outer edges of the canopy where the feeder roots lie but small oscillating sprinklers will also work. Drip emitters are not as effective. It will take at least 3 to 4 hours of slow irrigation for water to penetrate and soak the root zone.
Insufficient water is the most common cause of poor crop set and premature fruit and nut drop. Fruit and nut trees need regular deep irrigation to maintain consistently moist soil from bloom until harvest time. Citrus trees need sufficient water in spring to set fruit and regular deep irrigation in summer through fall in order to hold and produce good-sized, juicy fruit.
During heat spikes, monitor soil moisture levels under citrus trees and deep irrigate whenever the top three to four inches of soil has dried. Plan on irrigating citrus every 3 to 4 days during heat spikes in July and August and once a week during the warm fall months.
Cool-climate redwood trees have been heavily planted in the hot and arid Central Valley to provide dense shade. Often in spaces too small for the mature tree. As a common practice, redwood trees are thinned and lower branches are removed. The heavy branch structure on redwoods creates a cooler microclimate in the interior of the canopy and thinning and removing branches on redwoods exposes the trunk and bark to the hot rays of the sun and high temperatures.
In July, the inner needles on redwood trees will turn brown and fall. It's a normal process referred to as redwood dieback. The fallen needles form a thick mulch that will help cool the soil for these shallow-rooted trees and also slow evaporation. Redwoods will benefit from increased deep slow irrigation in summer.
Branch tip dieback is the earliest and most visible sign of drought-stress. Even one long-lasting heat spike without sufficient irrigation can cause tip die back on any type tree. Gusty winds now often accompany heat spikes. Dead branches can become hazardous projectiles and should be trimmed off when noticed, but corrective pruning to reshape branch scaffolding should wait until deciduous trees are dormant in late fall and winter.
- Author: Ryan Daugherty
I recently helped one of our local student gardens install a drip irrigation system in some raised beds. During the installation, I had to explain why we were using ½” tubing for most of our system instead of ¼”. Some believed that using the smaller tubing would give us better pressure, like putting your thumb over the mouth of a garden hose. I explained why this would actually result in less pressure and worse water distribution throughout our system. This misconception is common, so I thought I'd discuss it here.
If you think there's no way I'm about to talk physics in a garden blog, prepare to be amazed!
First, a review. Friction is the force that opposes the sliding or rolling of one solid object over another. There are a few different types of friction, but the one most relevant to our irrigation lines is kinetic friction.
Kinetic friction is the force that opposes the movement of two objects in contact while in motion. Think of it like using the brakes on a bicycle: when you pull on the brake lever, the brake pads contact the wheel, and the kinetic friction between the pads and the wheel opposes the wheel's forward motion, eventually stopping the bike. As water moves through our irrigation lines, it is in contact with the inside of the tubing. The kinetic friction between the water and the tubing surface opposes the water's forward motion, resulting in a loss of pressure. In irrigation lingo, we call this "pressure loss from friction" or just "friction loss."
If you could see a cross-section of your tubing while water was running through it, you wouldn't see a solid cylinder of water. Instead, it's more turbulent, with empty space, bubbles, and vortices. If the amount of water moving through the line remains constant and we decrease our tubing diameter, that empty space shrinks, and more water comes into contact with the sides of the tubing. More surface area of the water in contact with more surface area of the tubing generates more friction, resulting in more pressure loss.
Like tapping the brakes on a bicycle, there isn't much friction generated when it's just your thumb at the end of a garden hose. The real pressure loss comes from consistent friction over distance, like holding the brakes down until the bike stops. Multiply even a small amount of friction over any real distance, and you're looking at significant pressure loss.
In response to this, drip irrigation experts developed “rules” or guidelines for drip irrigation. For ¼” tubing, we call it the 30/30 rule: no more than 30 feet in any given run of ¼” line, drawing no more than 30 gallons per hour (GPH). More than 30 feet generates too much friction loss, and hydraulically only so much water can move through any given volume of tubing, hence 30 GPH. For ½” tubing, it's the 200/200 rule, for ¾” it's 480/480, and so on. As our system grows in length and demand, our tubing diameter has to increase accordingly.
If we don't match our system to the length and demand, we risk poor distribution uniformity. We might have to overwater or underwater one part of our garden to properly water another, leading to water waste and poor plant health. For most home landscapes, 1/2" tubing works well since we seldom run more than 200 feet on a single line.
These principles are simple but powerful, and by understanding them, you can make more thoughtful decisions in the design of your drip systems to get the most out of them.
- Author: Pamela S Kan-Rice
On May 7, scientists from University of California, Riverside, UC Agriculture and Natural Resources, Colorado State University Extension, Kansas State University, University of Arizona, Central Arizona Project, and USDA-Agricultural Research Service will gather with growers in Palm Desert to discuss how artificial intelligence can be used in agriculture.
“Artificial intelligence can be used by farmers to save water, improve fertilizer efficiency and increase productivity,” said Khaled Bali, UC Cooperative Extension irrigation water management specialist and organizer of the workshop. “At this workshop, growers will hear about the latest research on AI technology for agriculture and about the experiences of growers who are already testing it in their fields.”
Speakers and topics will include:
- Raj Khosla, Kansas State University - AI for precision nitrogen and water management in row crops
- Michael Cahn, UC Cooperative Extension - CropManage decision support tool for irrigation and nutrient management
- Daniele Zaccaria, UC Cooperative Extension - Citrus crop water use and open ET in the low desert of California
- Nan Li, UC Riverside - Estimating soil moisture using remote-sensing and land surface parameters in the Central Valley of California.
- Ali Montazar, UC Cooperative Extension - Promises and pitfalls of drip irrigation in desert cropping systems
- Khaled Bali, UC Cooperative Extension - Deficit irrigation strategies for alfalfa in California
- Philip Waisen, UC Cooperative Extension - Environmentally conscious practices for managing soilborne diseases in low desert vegetable production
- Peter Moller, Rubicon Water - On-farm water conservation projects: surface irrigation
- Ronnie Leimgruber, Imperial Valley grower - On-farm water conservation projects: linear move, basin and subsurface drip irrigation
- Rick Benson, Imperial Valley grower - Alternative cropping systems for the low desert region of California: olives and other crops
The workshop will be held at the UCR Palm Desert Center at 75080 Frank Sinatra Drive in Palm Desertfrom 8 a.m. to 3 p.m. on May 7. It costs $30 per person and includes lunch. Register at https://bit.ly/AImay7.