Posts Tagged: pH
Adjusting soil pH in California gardens
Soil acidity is an important factor for gardeners to consider when placing ornamental and edible plants in landscapes and vegetable gardens. It is possible to add amendments to the soil to adjust pH, but according to Dustin Blakey, UC Cooperative Extension advisor in Inyo and Mono counties, it's not always the best course of action.
“It is generally best to work with the soil you have, rather than try to attain the soil you wish for,” Blakey said.
Blakey wrote a six-page publication, “Adjusting Soil pH in California Gardens,” which is available for free download from the UC Agriculture and Natural Resources catalog.
In the new publication, Blakey describes how to quantify acidity, measure soil Ph, increase acidity and reduce acidity. Readers will also find typical desirable soil pH range for select garden plants, including fruit, nut and citrus trees, blueberries, avocados, azaleas, vegetables and lawns.
Download the full publication here: https://anrcatalog.ucanr.edu/Details.aspx?itemNo=8710.
Beets in Your Garden.
By Donna Woodward, UC Master Gardener of Napa County Few vegetables can boast the versatility of...
Beets. (healthline.com)
Beet variety. (johnnyseeds.com)
Beet tops vs Swiss chard--looks alike, and cooks alike. (thepersianfusion.com)
Boro beet, one of our test beets. (harrisseeds.com)
Lutz Green leaf beet. (oscseeds.com)
Detroit Dark red beet. (parkseed.com)
Thin seedlings and put thinnings in salad! (gardeners.com)
Protect young beets with row cover. (wimastergardener.org)
Bone meal may help beets grow better. Not recommending any particular vendor--just illustrating Bone meal. (missionhillsnursery.com)
Beets! (masterofhort.com)
Why Test Soils?
Because it is easier to correct a problem before you plant the trees than it is to diagnose and treat dying ones, which will probably be ripped out. A sad start to a tree is not a good ending.
In general, soil analysis is a measure of the physical, biological and chemical environment that a tree is going to be growing in. Is there going to be an impeding layer? Is it a waterlogged area prone to asphyxiation? A heavy soil that is going to need berming? Is it going to be too steep to harvest? These are physical properties that stand out and need to be considered.
Biological properties are harder to assess, but looking for old root channels and how healthy the previous crop grew are good indications of good biological health. How are those weeds growing?
The chemical side is often viewed from the nutritional and the toxicity angles. Trees are able to store nutrients in their various organs and have aids like mycorrhizae to help them take up some nutrients. So it's best to actually test the tree to see what their nutrient status is. Leaf analysis becomes the guide.
We do soil chemical analysis in trees primarily to identify potential toxicities. And for avocado trees, the main toxicities are high pH, salinity, sodium and chloride. Especially pH, which they like between 6 and 7. If it is corrected before the tree goes in the ground, it's relatively easy and inexpensive to correct. Once the tree is the ground, it takes a long time and energy and often it's hard to correct it without the tree dying. Like a waste of time and energy. But hey, I got the trees coming and it's time to be bold and act!! Let's plant.
And usually about a year after the tree is in the ground, the leaves start turning yellow and the canopy starts thinning. The tree was loaded up with iron in the nursery and after being in the high pH ground, it could not get enough iron and iron chlorosis set in. Well get ready to spend the next few years correcting the pH without killing the tree with sulfur or spending the rest of the tree's life messing with iron chelates. It would have been easy to apply a sufficient amount of sulfur in the planting area before planting, waiting for the sulfur to lower the pH, then planting.
Salinity, chloride and sodium are also important for testing prior to planting. Normally we think of these as chemicals that move with rainwater and irrigation. But in years when we have no rain, that doesn't happen. The light sprinklings we have can just move these salts a few inches into the ground and when trees are planted the salts migrate into the root zone. Even when berms are built and soil is scrapped into a hill, it's the surface soil that is being scrapped where all the salts are.
This situation can be compounded where there have been raspberry tunnels or flower tunnels previously and there has been no rain touch the ground the whole time the ground was covered. Or, where there was a crop with a high level of nutrients being applied and there could be levels high enough to affect the salt sensitive avocado. If you know salts are high, the soil can be leached before the trees are planted.
The effect of salt on the young trees can be almost immediate, within a week after planting. It can be dramatic and shocking.
Measuring sodium, chloride and salinity should be ongoing throughout the production years of an avocado. The status of the sodium, chloride and salinity are a reflection of how irrigation water is being managed. Is it getting enough, frequently enough? Was there enough rain to start the irrigation season without leaching?
Yeah, soil needs to be tested on a frequent basis. But the cheapest test and the easiest correction is done before planting. Do it.
Benefits of Composting with Coffee Grounds by Pam Snethen
Used coffee grounds are abundantly available for the asking at your local coffee shop. But just...
Controlling Soil pH with a Grass?
This is an intriguing article that popped up about how to improve blueberry production in alkaline soils. High pH soils are a major issues for many of our tree crops along the coast. pH is what controls the availability of most plant nutrients and what bacteria and fungi grow in the soil, creating the biosphere. So can growing a grass cover crop in our orchards improve lemon and avocado production?
A lawn is better than fertilizer growing healthy blueberries
Intercropping with grasses is an effective and sustainable alternative to chemical treatments for maximizing blueberry yield and antioxidant content in limey soils.
Blueberries are prone to iron deficiency - and correcting it increases their health-enhancing antioxidant content, researchers have discovered.
Published in Frontiers in Plant Science, their study shows that growing grasses alongside blueberry plants corrects signs of iron deficiency, with associated improvements in berry quantity and quality. The effects are comparable to those seen following standard chemical treatment - providing a simpler, safer, cheaper and more sustainable strategy for blueberry farming on sub-optimal soils.
What do superfruits eat?
All soils are rich in iron, but nearly all of it is insoluble.
"Most plants get enough iron by secreting chemicals that make it more soluble," explains senior study author Dr José Covarrubias, Assistant Professor of Agriculture Sciences at the University of Chile. "These iron 'chelators' can be released directly from the roots, or from microbes that grow among them, and allow the iron to be absorbed."
"Blueberries, however, lack these adaptations because they evolved in uncommonly wet, acid conditions which dissolve the iron for them."
As a result, most of the world's relatively dry or alkaline ('limey') cropland is unsuitable for optimal blueberry growth.
"Iron is essential for the formation and function of plant molecules like chlorophyll that allow them to use energy," Covarrubias continues. "That's why iron deficiency shows up as yellowing leaves - and drastically reduces plant growth and yield.
"And in blueberries, iron-dependent enzymes also produce the 'superfruit' antioxidants responsible for their celebrated blue skin and health-enhancing effects."
Strong blueberries must pump iron - but at what cost?
There are two approaches to correcting iron deficiency in blueberries: acidify the soil, or add synthetic iron chelators. Each has its drawbacks, says Covarrubias.
"The commonest industrial approach is soil acidification using sulfur, which is gradually converted by soil bacteria into sulfuric acid. The effects are slow and difficult to adjust - and in waterlogged soils, hydrogen sulfide might accumulate and inhibit root growth.
"Acids can also be added directly via irrigation systems for more rapid acidification - but these are hazardous to farmers, kill beneficial soil microbes, and generate carbon dioxide emissions.
"A commoner strategy among growers is application of iron bound to synthetic chelators - often sold as 'ericaceous fertilizer' - but these are very expensive and leach potentially toxic chemicals into the water table."
A cheaper, safer alternative is needed for efficient large-scale blueberry production. Thankfully, one already exists.
"Grasses - which are well-adapted to poor soils - can provide a sustainable, natural source of iron chelators via their roots when grown alongside fruiting plants. Intercropping with grass species has been shown to improve plant growth and fruit yield in olives, grapes, citrus varieties - and most recently, in blueberries."
A grassroots approach to sustainable blueberry farming
Now, Covarrubias and colleagues have brought intercropping a step closer to the mainstream of blueberry cultivation.
For the first time, they measured the effects of different methods of iron chelation on antioxidant content and other fruit qualities in blueberries.
"In an orchard of 'Emerald' blueberry bushes cultivated in alkaline (pH 8) soil, we compared the effects of five different iron chelation treatments: a 'gold-standard' synthetic iron chelator (Fe-EDDHA), intercropping with grass (common meadow grass or red fescue), cow's blood (Fe-heme), or no treatment (control)."
"We found the association with grasses increased not only the total weight and number of blueberries per plant, but also the concentration of anthocyanins and other antioxidant compounds in their skins, compared to control. The effect sizes were comparable with the proven synthetic chelator Fe-EDDHA, whereas applications of Fe-heme from cow's blood - a fertilizer commonly used in home gardens - had no significant effect."
The beneficial effects paralleled improvement in the plants' iron status (leaf color), which was also comparable between the grass-associated and the Fe-EDDHA-treated plants. None of the treatments had a significant effect on average berry weight
Turf is ready to roll out for healthier blueberries
A potential limitation of intercropping observed in the study was a decrease in berry firmness, since firmer berries are favored by consumers.
"The association with grasses decreased berry firmness compared with control plants, whereas the berries collected from plants treated with Fe-EDDHA reached intermediate values.
"However chemical analysis showed a non-significant trend towards increased ripeness in the berries collected from the intercropped plants, which could account for this small difference."
Intercropped plants also required an additional water supply to maintain a similar soil moisture to other treatments, but plant management was otherwise straightforward and the same across groups. The grasses were kept cropped between 5 and 15cm - a typical range for an attractive mown lawn.
"Our findings validate intercropping with grasses as a simple, effective, sustainable alternative to standard iron correction strategies in blueberries," concludes Covarrubias. "Both commercial and private growers can put this strategy to use right away to boost their blueberry crop and antioxidant content."
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Please link to the original research article in your reporting: https://www.frontiersin.org/articles/10.3389/fpls.2019.00255/full
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