Congrats to UC Davis Postdoc Olivia Winokur: Winner of AMCA's Hollandsworth Prize
Congratulations to UC Davis postdoctoral scholar and vector-borne disease specialist Olivia Winokur of the Chris Barker lab who won...
Congratulating Olivia Winokur (center), recipient of the Hollandsworth Prize for best student presentation at the American Mosquito Control Association (AMCA) annual conference are Casey Crockett (left), AMCA Student Competition coordinator, and Dennis Wallette, 2022-2023 AMCA president.
Time to Plant Bare Root Fruit Trees
Spring is springing! In a month it will be officially spring! The cherry, prunes, and pluots are all in agreement it's happening soon. In anticipation of spring, I planted 2 bare root trees, a dwarf peach and a persimmon. The best time to plant bare root fruit trees is the dormant season, late winter through early spring. You may still be able to plant a bare root tree.
I prefer bare root fruit trees for a number of reasons: they're less expensive; they're not as heavy or cumbersome: and, the roots haven't been circling in a pot. I paid for two trees for the price of one and a half. I was able to easily lift the trees and soil and put them in the trunk of my car. When I got ready to plant them, I just shook the dirt medium off and carefully combed the roots so they weren't crossing. Easy Peasy! Yeah!
Before you buy any tree, plan where you will plant it. Make sure there is well-drained soil. If the soil is not well-drained, you will have to amend it and perhaps plant the tree a little above the ground. Pick a location with plenty of sun 6 plus hours a day. Don't plant the tree too close to existing trees or shrubs. Envision a mature tree spreading its branches when picking a spot.
I have very hard clay and it were to plop down a tree into a hole with clay all around it would have a hard time establishing its roots. I chose to dig a large hole (wide but not deep). Make sure the soil is high enough so the root crown (root flare) would be slightly above the level ground. It's better to be slightly above the ground rather than burying the root crown. You can always add soil if you have too many exposed roots. The planting hole should be wide enough plus 6” to 12” for the existing roots to grow. Place the tree in the hole cover the roots with an inch or two of soil and soak the soil. Finish covering the roots to the surface and soak the soil again.
Dig the hole deep enough to plant the tap root fill surrounding area with potting soil mixture.
Don't leave the tags on the tree! The tree trunk will grow around them. Fill the hole with 1”-2” of soil dampen the soil and add more soil. Here I added potting soil the existing soil was clay.
New trees need water! Deep water twice a week. Slowly put water around the tree don't flood it, let the water soak in, repeat until the water stays on the surface and doesn't get absorbed into the ground. Mature trees need only be deep watered once a week. Water about 6” away from the tree trunk to encourage root growth. You should expect fruit in 2 in to 3 years.
Fruit trees take time to establish fruit so patience is a virtue.
Okay now you have the tree planted. It's time to take a pruning class. That's another blog!
Tips when planting bare root trees:
-Always buy from a reputable nursery
-Ask questions on how to care for your tree
-Check your growing zones for suitable tree species
-Keep the roots damp if you don't plant the tree immediately
-Don't put mulch directly up to the trunk leave 6” around the base
FOR FURTHER READING:
Harvest to table www.harvesttotable.com
Dave Wilson Nursery www.davewilson.com
Urban Tree Farm www.urbantreefarm.com
UC Master Gardener https://homeorcharducanr.edu/The_Big_Picture/Pruning_&_Training/
'Undescribed Species' Discovered at the Bohart Museum
"Spiders have been around for 400 million years and they are an incredibly diverse group with more than 50,000 species described with probably...
With UC Davis students (right) assisting at the Bohart Museum arts-and-crafts table, artists create arthropods and other critters, using modeling clay. (Photo by Kathy Keatley Garvey)
Siblings Camryn Baker, 9, Charlotte Baker, 6 and Thomas Baker, 8, all of Davis, finish their clay-modeling projects. (Photo by Kathy Keatley Garvey)
Aidan Laurel 3, and sister, Riley Laurel, 7 of Vacaville decide what to make. (Photo by Kathy Keatley Garvey)
How many legs? Charlotte Baker, 6, of Davis crafted this clay model at the Bohart Museum open house on "Many-Legged Wonders." (Photo by Kathy Keatley Garvey)
CA Climate-Smart Agriculture Survey for Ranchers
California Ranchers: We invite you to participate in a survey about California ranchers' and farmers' concerns, perceptions, information, and...
Study offers insights on reducing nitrate contamination from groundwater recharge
Light irrigation before flooding stimulates microbes to remove nitrates from soil
With California enduring record-breaking rain and snow and Gov. Gavin Newsom recently easing restrictions on groundwater recharge, interest in “managed aquifer recharge” has never been higher. This process – by which floodwater is routed to sites such as farm fields so that it percolates into the aquifer – holds great promise as a tool to replenish depleted groundwater stores across the state.
But one concern, in the agricultural context, is how recharge might push nitrates from fertilizer into the groundwater supply. Consumption of well water contaminated with nitrates has been linked to increased risk of cancers, birth defects and other health impacts.
“Many growers want to provide farmland to help recharge groundwater, but they don't want to contribute to nitrate contamination of the groundwater, and they need to know how on-farm recharge practices might affect their crops,” said Matthew Fidelibus, a University of California Cooperative Extension specialist in the UC Davis Department of Viticulture and Enology.
A recently published study by UC scientists sheds new light on how nitrates move through an agricultural recharge site and how growers might reduce potential leaching. Researchers analyzed data from two grapevine vineyards at Kearney Agricultural Research and Extension Center in Fresno County – one flooded for two weeks, and other for four.
Understanding initial nitrate levels crucial
A key factor in mitigating contamination is understanding how much nitrate is in the soil at the outset, said study author Helen Dahlke, a UC Davis hydrologist and leader of UC Agriculture and Natural Resources' strategic initiative on water. In areas with little precipitation and cropping systems that require greater amounts of synthetic fertilizer, the accumulation of residual nitrate – resulting from nitrogen in the fertilizer not taken up by the plants – can be quite high.
“The percentage of nitrates in some soils can really increase over the years, particularly if you have many dry years in a row where you don't have access to irrigation water or natural precipitation flushing some of those nitrates out of the soil,” Dahlke said.
While intense rains in recent weeks have helped dilute nitrate concentrations naturally, farmers looking to participate in recharge during the dry years ahead should consider flooding their fields with greater volumes of water.
“If you're doing this for the first time – on-farm recharge in the winter – check your residual soil nitrate levels because if they're very high, you should apply a lot of water in order to make sure that the residual nitrate is diluted down,” said Dahlke, who also added that growers should check their soil properties for suitability of recharge projects.
She recommended using, as a “good first approximation,” the online Soil Agricultural Groundwater Banking Index map, a project led by Toby O'Geen, a UC Cooperative Extension soil resource specialist.
Researchers looking at other ways to reduce nitrates
Even before flooding the fields for recharge, there are several practices that can lower initial nitrate levels and risk of leaching. Cover crops such as alfalfa and triticale, for example, can help take up residual nitrates that accumulate from fertilizing a main crop over time.
Dahlke and Fidelibus – a co-author of the San Joaquin Valley vineyard study – both pointed to pre-flooding irrigation that encourages denitrification, a process in which soil microbes transform nitrates into gaseous forms of nitrogen.
“Those denitrifying microbes need to be stimulated to do the work,” said Dahlke. “What we have found is that if you do a little bit of irrigation before you start the flooding, increasing the soil moisture can get those microbes started and they can take out more nitrate from the soil.”
The timing and quantity of fertilizer applications are also major factors in reducing leaching. Although more growers are following high-frequency, low-concentration practices to maximize uptake by crops, Dahlke said there needs to be more emphasis on incorporating nitrogen transformation processes – such as denitrification – in the nutrient management guidelines that farmers follow.
“Implementing thoughtful nutrient management plans will play a particularly important role in participating farms,” Fidelibus added.
A more holistic view of groundwater recharge
In short, choices made during the growing season can affect those in the winter recharge season – and vice versa. For example, applying compost or other organic amendments to soil can give microbes the “fuel” they need for sustained denitrification.
“What we have found is that our denitrifying bacteria often run out of steam because they don't have enough carbon to do the work,” Dahlke said. “Like us, microbes need energy to do the work, and for microbes this energy comes from soil carbon.”
Then, adding moisture via recharge to that field with high organic content can stimulate mineralization and nitrification, processes in which microbes transform the organic nitrogen into ammonium – and subsequently nitrates – that the plants can then take up. Those naturally occurring nitrates would thus reduce the need for the grower to apply synthetic fertilizer.
“The winter on-farm recharge experiments have shown that altering the moisture regime in the winter has consequences for the nitrogen budget in the summer growing season,” Dahlke explained. “Theoretically, what we need to be doing is better integrating both seasons by keeping an eye on the soil-nitrogen balance across the whole year so that we can ensure, at the end of the growing season, the residual nitrate in the soil is minimized.”
The study, published in the journal Science of The Total Environment, was part of the post-doctoral work of former UC Davis researcher Elad Levintal. In addition to Fidelibus and Dahlke, other authors are Laibin Huang, Cristina Prieto García, Adolfo Coyotl, William Horwath and Jorge Rodrigues, all in the Department of Land, Air and Water Resources at UC Davis./h3>/h3>/h3>/h3>