Cincinnati Soil Sessions

Once again I was fortunate enough to attend the International Meeting of the ASA, CSSA, and SSSA this time held October 21-24 in Cincinnati, OH. This year’s theme was ‘Visions for a Sustainable Planet’. I’d thought I would share a few of the ideas and research discoveries that I found particularly interesting or enlightening.

Our opening keynote speaker was Heather Hanson from the World Food Program USA who shared with us some thoughts on ‘The Real Dirt about Ending Global Hunger’. I bet you didn’t know that there are more hungry people in the world than the combined populations of the United States, Canada and the European Union – that’s more than 870 million people (1 out of 7). Or, that more than 2.5 million children die from malnutrition each year and those who do live are more likely to suffer from lifelong developmental and physical difficulties. Ms. Hanson laid the situation out well plus emphasized the need for attacking hunger on a global basis. Sooner or later it is going to impact all of us whether because of political unrest, economic instability, depletion of resources, pollution or climate change. 

Another prophetic speaker was Dr. Daniel Hillel, a renowned scientist and international authority on sustainable management of land and water resources. His timely topic was ‘Considering the Future of Agriculture and the Environment in a Changing World.’ Our world is changing quicker than most imagine because of population growth, consumer demand, climate change and the political unwillingness to base policies on science rather than on emotion. Our soils support all life on earth – including us. If we lose the ability to grow food, we die. Dr. Hillel highlighted the importance of wise soil management in lieu of changing climatic conditions and a society detached from the land.

Talks at the conference are typically15 minutes in length, just enough to whet your appetite and to make you want to find out more. An interesting talk by Dr. Donald Davis of the University of Texas gave some insight into why as the yields of many crops are increasing, their nutrition value is decreasing. Basically this is because breeders are selecting for plants with higher biomass which translates into more carbohydrates and possibly water but with the same amount of nutrients as the old variety. He and his research team looked at a number of crops – and found that as yields increased, the concentrations of minerals, vitamins and proteins in most vegetables, fruits and grains decreased. A most interesting point he brought up was that up until this research, many blamed the decrease in nutrients in produce on the depletion of nutrients in the soil over time. He showed that it is not the soil to blame for lower nutrients in many edible plant parts but instead it is caused by the plant (genetic dilution) itself! Backyard gardeners can grow older, more nutrient dense varieties.

Dr. Paul Ebner from Purdue University spoke on antimicrobial use in livestock production. I bet you didn’t know that the United States produces 15,000 TONS of antibiotics for livestock use each year! Not only that, but the antibiotics are not just used to make animals well but to improve growth efficiency. He noted that antibiotics are poorly absorbed by animals (maybe 10% or so) so the rest is just excreted and then where does the manure go? This is a major source of agricultural controversy that needs to be addressed because of the very real threat of creating antibiotic resistant bacteria that can make us humans ill. More research is needed and more precautions as well. Some studies have indicated effects of antibiotic-laden manure on important soil microbes.

Silicon is all around us. In fact, it is the second most abundant element in the earth’s crust, following oxygen. It is found in soils, rocks and dust particles in various forms of silicates or silica (silicon dioxide). Dr. Joseph Heckman from Rutgers University believes it has long been an overlooked yet essential plant nutrient and organized an afternoon-long symposium on this ubiquitous element. It has recently been designated by the Association of Plant Food Control Officials as a plant beneficial substance.

 Of particular interest was Dr. Lawrence Datnoff’s (Louisiana State University) presentation on silicon’s suppression of plant diseases, both root and foliage ones. Also silicon was shown to suppress diseases caused by fungi, bacteria, nematodes and viruses! It seems that the suppression of plant diseases improved as the silicon concentration increased in the plant. What is not clear yet is whether this effect is due to a mechanical effect or a cellular one so more research is needed. Also, it was noted that suppression occurred when the supply of silicon to the plant was continuous rather than interrupted. At any rate, I am going to try applying some potassium silicate to my cucumber plants in hopes of having less of a problem with powdery mildew next year.

Fountain Square

Yes, I did get out for a short bus tour of Cincinnati. Here’s a picture of Fountain Square where the opening shots for WKRP Cincinnati were taken and murals at the Cincinnati Museum Center. Best ice cream in Cincinnati – Graeters coconut!

Mural at the Center for Cincinnati Museums

Soil-fully yours!

Dawn

 

The Lowly Earthworm

Pile of earthworms. Urbanext.illinois.edu

The soils supporting our home lawns, vegetable and perennial gardens are improved by the presence and activity of earthworms. They are considered beneficial in the plant world. Earthworms move through the layers of soil creating tunnels for water and oxygen to reach the plant roots and channels for root growth. Their movement increases drainage and reduces compaction. Often called “nature’s rototillers”, earthworms feed on organic matter, bacteria, fungi and small soil particles in varying depths depositing their castings, or feces, in other horizons effectively turning the soil over. Castings are rich in nitrogen and nutrients easily absorbed by plants. Their feeding aids decomposition of organic matter, aerates soil, creates good soil structure and develops humus. The Rothamsted Experimental Station in England has done research finding as many as 250,000 earthworms per acre. That is a lot of subterranean work happening! Charles Darwin was one of the first scientists to recognize the benefits of earthworms. His last book written in 1882 is on the worm biology and behavior. His discoveries of earthworms are still being seen today.

Often after a rain, earthworms come to the soil surface then re-enter the ground head first. Some scientist think the worms come to surface for air if the ground is saturated. Others believe chemicals in the rain are inhospitable by changing pH and chemical amounts from acid rain. Still others think since the surface is moist, the worms come to the surface to mate. Earthworms are negatively affected by drying out by the sun therefore most surfacing happens at night. The action of tunneling back into the ground squeezes the worm leaving a pile of castings above ground. The casting look like tiny round balls piled up in a pyramid up to two inches depending on the size and type of the worm. Casting piles normally go unnoticed unless the turf is cut exceptionally short like that on golf course greens and tees. Home lawns should be cut to a height of at least three inches. Wet piles can stick to mowing equipment gumming up the blades and gears. The piles are easily dispersed once they dry.

Earthworms breathe through their skin. Oxygen is absorbed by mucous on the outside surface of the worm where it is transferred to the internal organs. This is called a gas exchange. The circulatory system of the earthworm contains five hearts or aortic arches. They pump fluids to blood vessels and capillary beds throughout the body circulating back to the hearts. The earthworm’s digestive system starts with its wide opening of a mouth that its throat or pharynx protrudes out of grabbing organic matter, soil particles and all that they contain. This food is swallowed down to a storage area called a crop. The food then moves to the gizzard where it is ground up by strong muscles and tiny stones and grit swallowed by the worm. Once the food is sufficiently ground, it moves to the intestines where digestive juices extract nutrients and some are absorbed by the worm. Excess digested food is then excreted as worm castings. It is these castings that are rich in nutrients readily available for plant roots to pick up. Earthworms don’t have eyes but are sensitive to light, vibration, touch and chemicals. They want to be in darkness and will move away from the light.

Chemicals added to lawn and garden can kill the earthworms. Preferred pH levels are neutral to 6.6. Adding lime in large doses can be too shocking of a change in their environment. Many earthworms will move to areas with better suited conditions or they may just die. Some insecticides and fungicides have lethal effects on earthworms. Researchers have also found earthworms within chemically treated soils to contain up to 20 times the toxin levels than the soil the worms inhabited. Stored toxins built up in the earthworms could then be passed up the food chain to animals using the earthworms as food.

Earthworms are classified as animal invertebrates. They are in the phylum group Annelida, meaning segmented worms.   Each segment contains four tiny setae or claw like bristles used to move through the soil.  Worms are hermaphroditic;  each worm has both male and female parts with the male pores located on the outside of the animal. Earthworms are not self fertile. They need another worm to mate and reproduce. Each worm is fertilized in the mating process called cross-fertilization.

The most common earthworms found in Connecticut are Lumbricus terrestris, called the Night Crawler, and Lumbricus rubellus called Red Worm. Night crawlers are known to venture deep into the soil in permanent vertical burrows. The will come to the surface to feed also. Red worms prefer to live in a manure pile or area with high organic matter. Both of these earthworms originated in Europe and were introduced to North America unknowingly on plant material, ship ballast, wheels and shoes of immigrants. Native earthworm finding are very rare. It is not known whether native types were wiped out by glaciers scraping the earth or if the new earthworm invaders displaced the old. Different theories exist. What is known is that the earthworms that are present today are many, active and busy decomposing and recycling organic matter in rich new topsoil.

There are some invasive worms originating from Asia that are causing problem in some areas of North America. They are such fast consumers of organic material they are changing the layers of soil and eliminating the forest floor called ‘duff’. Some birds nest in the duff areas to raise their young. Insects and animals that also reside and feed in the fast disappearing habitat are also finding it hard to live. The effect of the exotic worms in the local habitat really is upsetting the ecological balance. Some populations that depend on the areas the worms are ruining might vanish forever. Research is presently being done but much more needs to happen. So does education of the general public. Some fishermen are using invasive worms for bait, then just dumping the leftovers on the ground. They are unknowingly spread the invaders. ATV and off-road enthusiasts also can pick up soil, worms and eggs in tire treads, then depositing them far from the initial infected site. Hopefully in the not too far future, more information and education programs will be available. Keep watching!

-Carol Quish

 

 

Digging Dirt!

Last Saturday, the Connecticut Community Gardening Association (with a little help from their friends at UConn, CT NOFA, SSSSNE, Knox Parks, New Haven and Bridgeport Land Trusts, and Hartford Food System) held a free showing of ‘Dirt – The Movie’ at the Berlin Peck Public Library. For those not familiar with CCGA, they are a small organization whose mission is to promote and support community gardening in Connecticut. I got involved with this volunteer organization several years ago and am presently serving as secretary. Our website is www.ctcommunitygardening.org.

We know of at least 44 towns and cities in the state with active community gardening programs and one of CCGA’s ongoing projects is to maintain a list of them so folks looking for some community gardening space can find out what is available to them. Community gardens can be found in big cities like Hartford, New Haven and Bridgeport as well as small towns like Guilford and Mansfield. They provide many CT residents with a source of nutritious and inexpensive food as well as a sense of community that culminates in interaction among various community groups and a source of pride in the neighborhood.

Community Garden in Willimantic

CCGA has held educational conferences in various locations throughout Connecticut for a number of years now but this year we decided to offer a free movie screening in Berlin and perhaps in other parts of the state as well. ‘DIRT – The Movie’ deals with a topic near and dear to all gardeners’ hearts – Soil! The movie was inspired by the book, Dirt: The Ecstatic Skin of the Earth by William Bryant Logan. For too long we have been taking the earth beneath our feet for granted. The soil nourishes all forms of life including our own. It is a living, breathing ecosystem and this thin covering over the earth’s surface needs to be appreciated and cared for so that it can continue to sustain the life of future generations of plants, people and animals.

This wonderful movie helps us reconnect to the soil. Real people talk about their relationships with the soil, relate how the neglect and abuse of the soil can lead to societal, economic and environmental problems, and then they offer us hope because this living, renewable resource can be brought back into a productive state through our actions and awareness. Several of the viewers who came to the screening were amazed that soil could be such an interesting topic!

Soil from outwash plain in CT

A few facts to consider about our soils:

Soils are natural bodies composed of minerals and organic materials, liquids and gases, and countless macro and micro-organisms.

Like plants and animals, soils also have a classification system called soil taxonomy. The highest level is called a soil order; the lowest level is called a soil series. In the United States, there are at least 23,000 soil series.

Soils have unique chemical, physical and biological characteristics which affect the type of life they support both above and below ground, and which determine the appropriate use for that soil.

There may be more microorganisms in a cubic foot of healthy soil than there are people on earth!

Erosion of soils is a worldwide problem. We need healthy soils to grow our food. It is estimated that worldwide 24 billion tons of topsoil are annually lost to erosion!

If you get the chance, see the movie. Do a little digging on your own to find out more about soils and how to treat them with the respect and care they deserve.

“A thin layer of earth, a few inches of rain, and a blanket of air make human life possible on our planet. These essential resources must be available to provide the good life for our children and for future generations.” John F. Kennedy

Dawn