- Author: Jane Callier
Sadly, the damage doesn't end there. These conditions change weather patterns and impact water supplies. It's no wonder bare soil is another element in global warming. I remember my first-grade teacher discussing an article the class had read in “My Weekly Reader” about farming and the notion of leaving a field fallow for a season or two to rebuild fertility. Such was the thinking in the 1950s, and I thought the notion sounded perfectly reasonable. Of course, nothing could be farther from the truth. Unplanted bare soil degenerates and the carbon cycle stops working.
Alternatively, the process of photosynthesis is a cooling, or endothermic activity as plants make their carbohydrates. There is a net water gain if land has a continuous population of plants. The conventional agriculture practice of tilling renders a net water loss. If the soil is planted with a cover crop, water can keep infiltrating the soil, and life beneath the surface keeps functioning and staying healthy. Legume cover crops like fava beans and clover are good choices because they return a significant amount of nitrogen to the soil. This is achieved when the plants are chopped down and left on the soil. Using fast-growing buckwheat for a cover crop will feed pollinators. Mustard and brassica will fumigate the soil for nematodes. Grass roots hold soil in place and help keep the ground cool. All of them attract beneficial organisms, pull down carbon from the atmosphere and help retain water.
Mulching is another good practice to keep the ground cool. Two inches of compost should first be laid down, then three inches of mulch. Straw is an excellent, organic cover for garden beds. Mother nature can help by using leaves to mulch if we can get past another unuseful habit (besides tilling the soil) of demanding our gardens be perfectly manicured. It's always a good idea to spread compost, but the reason we do it before we mulch is that some mulches, such as wood chips, can leach nitrogen out of the soil. If we apply compost first, the effect will be buffered.
If we follow these practices, we will improve the tilth of the soil, promote soil organic matter (SOM), retain moisture in the ground, prevent leaching of soil minerals, attract soil organisms, and improve the yield and nutritional value of our fruits and vegetables.
Our takeaways are these:
Bare, tilled soil contributes to global warming.
Cover the soil with living plants.
Use cover crops.
When this isn't practical, add compost and mulch.
*This is the fourth post in this series following concepts and information from UC Master Gardeners of Napa County presentation, “Soil is the Solution, healing the earth one yard at a time,” https://www.youtube.com/watch?v=JqA8DqBtRuo . The presentation describes practices we can learn and implement about soil to help slow and ultimately reverse the damage humankind has done and slow global warming. Previous posts were May 24, June 7 and June 28, 2021.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Pixabay
- Author: Jane Callier
Humans have been stripping mother earth of her verdant, life supporting cloak for a long time, but the damage has shot up to a critical stage during recent years. To extend the metaphor further, earth has been stripped so bare that ecological systems are out of balance. Global warming is a reality, extreme weather and climate situations are causing drought, wildfire, increased land/sea temperature differences, wet areas are wetter and dry areas are drier. We need to help mother earth regain her cloak and soil is the fabric of her cloak.
Following are excerpted concepts and information from UC Master Gardeners of Napa County presentation, “Soil is the Solution, healing the earth one yard at a time,” https://www.youtube.com/watch?v=JqA8DqBtRuo . The presentation describes practices we can learn and implement about soil to help slow and ultimately reverse the damage.
Natural processes have been doing this on their own for thousands of years. Increasing soil organic matter is the first practice from the presentation to make healthy soil. Elegantly simple, to increase life in earth's over-tilled and compacted soil we can add compost. Other ways to help add organic material to the soil are using mulching mowers, letting fallen leaves decompose, and implementing a chop and drop system as you groom your garden.
Soil management is key to maintaining healthy aggregated soil. Even one application of compost helps to decrease the carbon level in earth's atmosphere and it creates nutrient-rich humus that is a natural fertilizer. Compost greatly benefits plant growth and water is maintained in the soil longer helping to conserve it. It also adds microscopic organisms that work to aerate the soil, break down organic materials and fight off plant disease and insects. Another benefit is your compostable trash will be kept out the landfill, helping to reduce methane gas.
Regenerating the soil is a natural, inexpensive way to reduce greenhouses gases and is right under our feet. Next up: Use compost, not chemicals.
Master Gardeners are following recommended social distancing guidelines that keep everyone safe, Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: USDA NRCS (CC BY-SA 2.0)
by Rainer Hoenicke
If you could continually turn a lot of organic material into biochar, you could, over time, reverse the history of the last two hundred years…We can, literally, start sucking some of the carbon that our predecessors have poured into the atmosphere down through our weeds and stalks and stick it back in the ground. We can run the movie backward. We can unmine some of the coal, undrill some of the oil. We can take at least pieces of the Earth and – this is something we haven't done for quite a while – leave them Better Than We Found Them.
Bill McKibben, author, climate activist and founder of 350.org
Characteristics of Biochar
Biochar is essentially organic material that is heated at temperatures above 700 degrees F with limited oxygen supply - a process called pyrolysis. The carbon molecules in organic material are generally arranged in hydrocarbon chains, which are easily broken apart in the decomposition process. When burned in a low-oxygen environment, the material doesn't leave ash as a residue but turns into something very much akin to charcoal. The hydrocarbon chains in un-decomposed organic matter are transformed during this pyrolytic process into rings, which don't break down easily. Some call biochar “stabilized organic matter.” Carbon in biochar can persist in soils over long time scales. Beyond the carbon sequestered in the biochar itself, biochar incorporated in soils also offers numerous other potential benefits.
1) Soil Fertility and Biodiversity: Biochar can improve soil fertility, stimulating plant growth, which then consumes more CO2 in a positive feedback effect. Biochar can reduce the need for chemical fertilizers, resulting in reduced emissions of greenhouse gases from fertilizer manufacture. Biochar can increase soil microbial life, resulting in more carbon storage in soil. Soil carbon has been shown to double after six years of bioachar applications of 2-10 tons per acre. Biochar and compost complement each other. With as little as 8% by volume added to compost, biochar accelerates the decomposition process and greatly reduces losses of ammonia to the atmosphere by facilitating conversion of ammonia to nitrate.
2) Water conservation: Biochar can hold as much as five times its weight in water, most of which remains available to plants. It improves the percentage of water available both in sandy and heavy clay soils and improves infiltration and percolation rates. A one percent increase in organic carbon in the top seven inches of the soil profile can increase water holding capacity by roughly 26,000 gallons per acre. For an irrigated vineyard, for example, water consumption could be reduced by almost 25%.
3) Reduced N2O and CH4 emissions: Biochar can reduce emissions of nitrous oxide (N2O) and methane (CH4)—two potent greenhouse gases—from soils as well as from composting facilities and landfills.
4) Reduced emissions from organic material: Converting agricultural and forestry waste into biochar can avoid carbon dioxide and methane emissions otherwise generated by burning or the natural decomposition of the waste.
5) Funding source for vegetation management in fire-prone areas: Small, distributed biochar generation facilities using slash and timber burned in wildfires may become a net funding generator for critically needed vegetation management. Currently, biochar costs $250-300 per ton, including delivery.
6) Energy generation: The heat energy—and also the bio-oils and synthesis gases generated during biochar production can be used to displace carbon from fossil fuels.
Small or medium-sized biochar production may be considered not only for landowners living in or near the urban-wildland interface, commonly known as WUI, but also for those UC Master Gardeners that produce a lot of potential “feedstock” for biochar (i.e., raw biomass, such as branches and other plant trimmings, trees and shrubs killed by fire). Below are some weblinks with a lot of additional information and resources available to those interested in not only improving their garden soil health but at the same time achieving water conservation and carbon sequestration goals.
Chapters 5 and 6 in: https://apps.ecology.wa.gov/publications/documents/1907027.pdf
Fundamentals of Soil Health – workshop sponsored by the Resource Conservation District of Napa County – the biochar talk by Josiah Hunt starts about 38 minutes into the youtube video : https://www.youtube.com/watch?v=II8EyXuk5Ds&feature=youtu.be
https://biochar- us.org/welcome-new-biochar-learning-center
Master Gardeners are following recommended social distancing guidelines that keep everyone safe, Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Oregon Department of Forestry, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
By Rainer Hoenicke
Key factors related to the decline of Monarchs are overwintering habitat loss along the coast, breeding and migratory habitat loss, as well as direct and indirect pesticide impacts. Master Gardeners can certainly contribute to spreading the word about applicable practices that can reverse at least two of the key factors of butterfly declines. The information resources that NRCS offers via the agency's website are immense. Many of them are on platforms that are map-based and interactive, such as e-Veg Guide at www.calflora.org/nrcs. That guide can show the various plants and their blooming times that benefit Monarchs during their migration times. The NRCS also has easily accessible technical guides with information about the conservation of soil, water, air, and related plant and animal resources (https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/technical/cp/ncps/?cid=nrcs143_026849). Each conservation practice is listed alphabetically and by number. Jennifer provided a brief overview of each applicable practice, among them Wildlife Habitat Planting and Conservation Cover (#420 and #327, respectively), Hedgerow Planting (#422), and Restoration of Rare or Declining Natural Communities (#643). Certain trees and shrubs can provide year-round beneficial monarch habitat for nectar, shelter, shade, and roosting. Coyotebush, e.g., is an important nectar plant from late summer through winter. If concerned about seed spread, you can buy male plants only at nurseries.
She also discussed direct and indirect pesticide impacts on Monarchs. The current generation of extensively used insecticides, called neo-nicotineoids (or “neonics”), have been detected in plant tissues at concentrations that can impact feeding larvae and contribute to their already high mortality rates (https://www.frontiersin.org/articles/10.3389/fevo.2020.00162/full ).
Neonics degrade only slowly, with a half-life of up to 280 days in soil (https://www.researchgate.net/figure/Half-life-in-Soil-of-Neonicotinoids_tbl1_233795128).
An example of indirect pesticide application impacts is that of applying broad-spectrum weed killers that milkweed species are particularly sensitive to (e.g. Roundup).
Jennifer also listed the native California milkweed species and their bloom times. Asclepias californica and A. cordifolia are early-blooming species, unlike the more commercially available species of showy and narrow-leaf milkweeds that bloom mid- to late-season. Asclepias cordifolia and A. eriocarpa are extremely tolerant of dry, rocky terrain and can survive the dry season without irrigation just fine. The Xerces Society has a milkweed seed-finder on their website, in case you want to create your own milkweed patch in your back yard or get one established in your sidewalk strip, instead of that thirsty Dichondra lawn (https://www.xerces.org/milkweed/milkweed-seed-finder).
Master Gardeners are following recommended social distancing guidelines that keep everyone safe, Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: public domain
Natural Resources Conservation Service (NRCS) biologist, Jennifer Kubel, presented a webinar on August 26, 2020, on agricultural and horticultural practices that could benefit Monarch butterflies. As many of us know by now, the western population has declined drastically by more than 90% since the 1980s. What can landowners do to help? That was the key topic of the webinar. While the intended audience was mostly agricultural producers that operate on much larger scales than horticulturalists and hobby gardeners, many of the conservation practices are applicable even at small scales.
She also discussed direct and indirect pesticide impacts on Monarchs. The current generation of extensively used insecticides, called neo-nicotineoids (or “neonics”), have been detected in plant tissues at concentrations that can impact feeding larvae and contribute to their already high mortality rates (https://www.frontiersin.org/articles/10.3389/fevo.2020.00162/full ).
Neonics degrade only slowly, with a half-life of up to 280 days in soil (https://www.researchgate.net/figure/Half-life-in-Soil-of-Neonicotinoids_tbl1_233795128).
An example of indirect pesticide application impacts is that of applying broad-spectrum weed killers that milkweed species are particularly sensitive to (e.g. Roundup).
Jennifer also listed the native California milkweed species and their bloom times. Asclepias californica and A. cordifolia are early-blooming species, unlike the more commercially available species of showy and narrow-leaf milkweeds that bloom mid- to late-season. Asclepias cordifolia and A. eriocarpa are extremely tolerant of dry, rocky terrain and can survive the dry season without irrigation just fine. The Xerces Society has a milkweed seed-finder on their website, in case you want to create your own milkweed patch in your back yard or get one established in your sidewalk strip, instead of that thirsty Dichondra lawn (https://www.xerces.org/milkweed/milkweed-seed-finder).
Master Gardeners are following recommended social distancing guidelines that keep everyone safe, Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Courtesy of Idaho Dept. of Fish and Game
