- Author: Ben Faber
http://ucanr.edu/blogs/confluence/
Water woes are probably not going to go away, so readup on how to best manage water at this new blog.
- Author: Rachael Long
Guest post from Rachael Long, UC Cooperative Extension Farm Advisor, Yolo County
The Yolo County Flood Control and Water Conservation District (YCFC) is an agency that supplies water to farmers in northern California. The agency is at the forefront of innovative efforts aimed at banking groundwater by diverting flood waters into their unlined canals. This gives flood waters time to infiltrate soils and recharge groundwater.
Using a water right permit that they recently obtained from California's State Water Resources Control Board, flood waters from recent storms are being captured from Cache Creek as it enters the Sacramento Valley. YCFC recently opened their lateral gates, allowing the flood waters to...
- Author: Faith Kearns
Groundwater wells can fail in many ways. Sometimes the water table sinks below the level of the well. Sometimes minerals cause buildup in well systems. And, sometimes, wells get clogged with lots and lots of microbes.
Microbes can form large, jelly-like mats that lead to well failure from what is known as biofouling. Biofouled wells can be both expensive and technically challenging to repair. There are even times that repair is not possible and replacement is the only option. In Washington State, for example, researchers have encountered well pipes completely clogged by mats of bacteria....
- Author: Faith Kearns
California's Sacramento-San Joaquin River Delta region, commonly referred to simply as the Delta, is often described as a unique part of the world. Although it is located between two big urban centers – the greater Sacramento and San Francisco Bay areas – the Delta can feel like another world altogether.
This is something Michelle Leinfelder-Miles, a farm advisor with UC Agriculture and Natural Resources, knows well. She comes from a sixth-generation farming family in San Joaquin County and, after accepting her position several years ago, was happy to return “home”...
- Author: Faith Kearns
The California drought has shined a spotlight on stories of people and communities living without water. Unfortunately, lack of access to clean and affordable water is not a new issue. Water security has been an enduring challenge across the state in wet and dry years alike, particularly for disadvantaged communities. Trying to meet concerns about water availability and affordability with pragmatic action is where things get both complicated and interesting.
One approach that the state has invested a great deal in exploring is known as integrated regional water management. While it is a complex topic, the basic idea is that there are multiple needs for water throughout the...
- Author: Faith Kearns
Street-side stormwater facilities are turning runoff once seen as a nuisance into a resource. Also known as bioretention areas, rain gardens, and bioswales, these small stormwater facilities provide a decentralized approach to alleviating peak stormwater runoff and subsequent flood damages. These are particularly critical functions in cities like San Francisco where the storm and sanitary sewer systems are combined because they help managers to prevent dreaded “combined sewer overflow” events. As a bonus, stormwater facilities have also proved useful in promoting groundwater recharge and filtering pollutants as water percolates through soils.
While street-side facilities are effective in helping to manage...
- Author: Ben Faber
At a recent meeting in Modesto covering drought and how it is being dealt with around the world, there was an interesting presentation by some Israeli researchers. They looked at the use of recycled water from sewage treatment plants and the use of desalinated water from the Mediterranean. The recycled water had much of the original mineral nutrients, but had been treated for microorganisms. They wanted to know how much of the nutrients could be accounted in the fertilizer balance applied to apple, pear and nectarine orchards. Their conclusion that after one year, there was a significant contribution and that leaf analysis had not changed, not yields after applying the effluent. This was only for one year, but I could imagine that after many years there would be a significant impact.
They also looked at desal water, and found that the process removed most minerals except for boron. They actually found that plants irrigated with this water ended up with calcium and magnesium deficiencies and more boron toxicity. The reverse osmosis membranes used in this case were not very effective at removing boron. In the case of many waters north of Los Angeles there are often high levels of boron in the water, and using RO water might accentuate the problem.
RO water also is usually too pure and the lack of salt causes soil to deflocculate - lose structure. Yes, you need some salt to have a healthy soil.
Read more about this trial at:
http://media.wix.com/ugd/7df67b_0bd44a0fe135459eb345ba31b96f232b.pdf
Bitter Pit in Apple caused by low Calcium
- Author: Ben Faber
The calls are coming in and have been for the last several months. The trees are tired, worn out and look horrible. What's the problem? Well four years of drought, accumulated salts in the root zone and irrigation practices that aren't removing the salts from the root zone. It sets up a situation of tip burn, but much more extensive than tip burn is the water stress that results from salt accumulation. Salts compete with roots for water and they act to pull water away from the roots. It is as if less water is being applied. The water stress sets up the trees for a fungal infection called variously leaf blight, stem blight and in young trees, death. We used to call this Dothiorella blight, but since the work of Akif Eskalen at UC Riverside, it turns out it is one of many fungi that cause this problem, most of them Botryosphaerias.
The leaves show what would appear to be salt burn damage which increasingly causes leaf drop. In fact, there's often a pile of leaves under the canopy unless the wind has blown them away. The difference between this and salt burn is that there is not a regular pattern to it. It can start on the margins, or in the middle of the leaf, or wherever it darn well pleases. Whereas salt/tip burn always starts at the leaf tip and progressively moves back onto the main part of the leaf. Leaf blight (I don't like to use bigger words than that – Botryosphaeria. Try spelling it on the phone), on the other hand doesn't follow this regular pattern. It's a random pattern.
This a decomposing fungus. Wherever there is organic matter – leaves, twigs, branches, fruit, whatever is dead on the ground – there is a decomposing fungus. When the fungus finds a stressed plant, it invades the most susceptible part of the plant, usually the leaf. It starts growing through the tissue and down the leaf petiole. It then starts growing down the dead part of the plant. Most of a tree is dead. All that stuff under the bark and cambium is dead tissue, although it still carries water. In mature trees, there is a capacity to close off the decay and limit it. In young trees (younger than two or so), the capacity is lacking and the fungus can keep on growing down to the union and kill the tree.
As can be imagined, this fungus does not discriminate amongst the type of plants it feeds on. It will go to water-stressed, citrus, roses, apples, etc. It goes to every woody perennial that I am aware of. I've seen it on redwoods and eucalyptus. It especially goes after shallow-rooted species like avocado which are the most prone to water-stress. Like when a Santa Ana blows in and the irrigation schedule is slow to respond. Like when there is a heavy load of fruit. Fruit have stomata and the more environmental stress the more water they lose and pull on water from the tree.
Now imagine a tree loaded with fruit, in the later summer, with a Santa Ana and salt stress. Boom! Fruit drops and leaf blight shows up. And the damage doesn't go away, until it so severe that the leaf drops and new leaves come on in the spring.
Hopefully these rains will wash the salts from the root systems and refill the profile with high quality water. We are extremely reliant on winter rain to cover up the effects of the damage that irrigation water does to our soil and plants. And rain is the answer, as long as it's not too much.
Notice the even pattern of necrosis with tip burn
And the random pattern with leaf blight.
- Author: Ben Faber
It ain't over yet, and this last week we had a wonderful 2 day meeting with folks who have dealt with drought in many different ways. Here are presentations made by people from Israel, Australia and California. Soon the actual videos will be available, but now see the powerpoints.
http://www.droughtmgt.com/#!presentations-and-documents/niui7
The grower panels are wonderful, but are not uploaded at this point
DAY I: UNDERSTANDING IRRIGATION WATER MANAGEMENT
Session I: California Response to Drought
9:15am // Overview of California Drought Response
9:30am // El Nino Forecast for California and Possible Impacts on Irrigated Agriculture
Session II: Technology of Water Management
9:45am // Soil Water Sensing
10:15am // ETc Estimates - Weather Stations (CIMIS), surface renewal
11:00am // Salinity Measurement
11:30am // Consideration In Selecting Water Stress Indicators
12:00pm // Precision Water and Fertility Management During Deficit Irrigation
Session III: Alternative Water Supplies
1:30pm // Irrigation With Recycled and Desalinated Water
2:00pm // Effects of Irrigation With Poor Quality Water on the Soil - California Experience
2:30pm // Effects of Irrigation With Poor Quality Water on the Soil - Israeli Experience
3:00pm // The Challenge of Sustainable Irrigation with Water High in Salts: Lessons from Dates, Olives and Grapevines
Session IV: Water Management Strategies During Drought
3:45pm // Water Management Strategies during Drought - Australian Experience
4:45pm // Cultivation Under Protective Structures to Save Water
Day II: WATER MANAGEMENT FOR INDIVIDUAL CROPS & GROWER EXPERIENCES
Session V: Technology Demonstrations​
8:00am // Irrigation Scheduling - Australian Experience - IrriSAT Approach (IrriSAT Supporting Materials)
8:30am // Using the Pressure Chamber for Drought Mangagement Decisions
9:00am // Irrigation System Evaluation
9:30am // Salinity Mapping for Water Management
Session VI: Conncurrent Breakout Groups
10:30am // Citrus - Israeli Experience: Long Term Effects of Deficit Irrigation, Salinity, and Rootstocks on Orchard Productivity
10:30am // Grapes - Table and Wine Grape Irrigation Scheduling
10:30 // Deciduous Nut Crops - Irrigation and Crop Load Interactions
10:30// Almond Irrigation, the Israeli Experience
11:15am // Olives - Israeli Experience: Cultivation Under Limited Water Availability
11:15am // Grapes - Wine Grapes Irrigation - Coastal Vineyards
11:15am // Deciduous Nut Crops - Almond Irrigation - Israeli Experience
1:00pm // Avocado - Israeli Experience
1:00pm // Grapes - Wine Grapes Irrigation: San Joaqin Valley
1:00pm // Deciduous Nut Crops - California Experience
1:30pm // Deciduous Nut Crops - Pistachios Irrigation
1:45 // Subtropical Crops - California Experience
1:45 // Grapes - Irrigation, the San Joaquin Valley
2:00pm // Deciduous Nut Crops - Walnut Irrigation
2:30pm // Grower Panels
3:15pm // Concluding Remarks