On Tuesday I went to a field day on no-till tobacco production. Tobacco is a warm season solanaceous crop -- like tomatoes or peppers -- that is usually transplanted into freshly-tilled soil in late spring. After fall harvest the remaining stubble is usually left to decompose in the bare soil until the next spring, when the plow comes around again.

In recent decades people have started to recognize that soil suffers when it's left bare, or routinely disturbed by cultivation. Bare soil is susceptible to wind and water erosion. Cultivation destroys the soil structure, further increasing its susceptibility to erosion. Cultivation also introduces a lot of oxygen to the soil very quickly, resulting in a brief boom in the microbial population, and a rapid depletion of the soil organic matter that the microbes eat. (Organic matter is a valuable component of soil because it holds on to the nutrients and water that plants need; soil microbes help release nutrients into the soil solution, making them accessible to plants, and exude sticky material that holds soil particles together, reducing soil's susceptibility to erosion.) In the long term, cultivation reduces soil organic matter content and soil microbial populations.

No-till grain production is now fairly common, but very few farmers grow transplanted crops, like tobacco, without cultivating. It turns out that one of them happens to be a sixth-generation Kentucky farmer who took the 'Introduction to Sustainable Agriculture' course that I co-taught last semester. The field day was at his farm.

We saw a nice demonstration of how soil that hasn't been tilled holds together better than soil that is routinely cultivated. Clods of soil collected from sections of the farm that hadn't been cultivated for 10 years were suspended in water next to a clod collected from a routinely cultivated section. You can see the clod on the left disintegrating while the clod in the middle holds firm:

After harvest the land is seeded to a winter cover crop that protects the soil from winter erosion, saves nutrients that might leach out of the soil in the absence of plants, and feeds soil microbes. The farm is experimenting with different winter cover crop mixes, most of which include a nitrogen-fixing legume species.

At the Kentucky State University Research and Demonstration Farm we often use a mixture of rye, which grows quickly and out-competes weeds; and hairy vetch, which fixes nitrogen and twines its way up the rye. Here are the two plants together, towering over a yardstick:

Nitrogen-fixing crops like hairy vetch harbor bacteria in their roots that are able to convert nitrogen gas from the air around us into nitrogen that is available to plants. A winter cover crop of hairy vetch can add more than 100 pounds of nitrogen to the soil per acre (Kansas State University pdf), enough to feed a nitrogen-demanding crop like corn.

Of course organic farmers have been using nitrogen-fixing cover crops for decades; the organic standards don't allow synthetic nitrogen fertilizer. Conventional farmers have known about the advantages of cover cropping, but using nitrogen fertilizer has long been cheaper than managing cover crops. Soaring fertilizer prices have changed that. Suddenly tactics like no-till production and cover cropping aren't just better for the soil; they're cheaper, too.

Michael Bomford provides research and extension services related to organic agriculture and small-scale renewable energy production through Kentucky State University's Land Grant Program.

Over the weekend a group of thinkers working with Post
Carbon Institute have been discussing the mineral content of rain. Often
when we discuss minerals and rain we are talking about the manner in which
minerals and inorganic nutrients are readily leached from the soil. Leaching is when minerals are not able to hold
in the soil and are thus washed out by the natural flow of groundwater. A soil’s
tendency to leach is influenced by the way that the soil is tilled, cropped,
and fertilized.

For instance, inorganic fertilizers provide crops with plant
available nutrients in the form of chemicals like nitrate (NO₃^-).
The problem is that nitrate readily washes out of the soil if the plants are
unable to utilize it before heavy rains. Many farmers are beginning to realize that
heavy fertilizer application in the fall amounts to a waste of money since a majority
of the nutrients are lost by spring due to sever washout by winter rains or
spring snow melt.

Leaching of minerals also occurs when soil is left bare to
face winter rains. In this case, leaching is accompanied by a loss in top soil
from the process of erosion. Imagine rain drops as tiny explosions on bare
soil, blasting minerals loose, collecting in water particles, and flowing away
as surface runoff.

Fortunately, farmers do not need to resign to the fact that
rains always mean a loss in minerals and nutrients. By cover-cropping and the
addition of compost, a farmer can protect the soil from direct rainfall and increase
the organic matter in the soil in the form of root biomass. Roots and organic matter
create a healthy habitat for soil microbes that play a key role in mineralizing
soil nutrients and forming soil aggregates that resist leaching.

One great benefit to having a diverse soil food web of
fungi, bacteria, and protozoa is because organic minerals are “sequestered” in
the biomass/bodies of microbes and recycled through in their metabolic
processes. Instead of washing out of the soil, the minerals actually become the
body of bacteria and fungi! In a series of food chain and energy exchanges the
minerals in the soil are converted from one form to the next; changing from plant
detritus to the body of a soil organism, then to metabolic wastes of that
organism and into plant available forms of, and then consumed and incorporated into
the body of another soil microbe. All these changes occur in and around in the
rhizosphere (root-zone) of plants, and demonstrate an interconnected web of
energy and nutrient cycling and nutrient retention.

Also consider the fact that bacteria and fungi create a natural
glue that sticks to everything. Through the production of “glomulin”, nutrients
are retained and soil aggregates are formed. As organic matter is decomposed, the
biology in the soil help to form stable negatively charged humic (humus)
molecules which bind together with positively charged cat ions, electrically holding
minerals and preventing them from leaching. Important cat ions retained in
colloidal humus particles include: calcium, iron, magnesium, potassium, sodium,
and copper.

As you can see, there is a lot happening below the
soil, and farmers and gardeners have an opportunity to utilize cover crops, compost,
soil biology, and appropriate timing of fertilization to prevent soil erosion
and leaching of nutrients.

Broadcasting a Cover Crop of Crimson Clover in October to Protect Bare Soil from Winter Rain

Recently Sown Cover Crop of Legumes mixed with Rye and Barley Provides Root Biomass and Use Boilogy to "Fix" Nitrogen from the air

For years, many farmers have applied fungicides to battle against certain
species of fungi that devastate their crops. While this method has appeared
necessary for years, a revival is occurring where farmers are looking to work
with nature in place of a “no-hold barred” war against it. Indeed, it is
possible (and profitable) to use soil biology to fight pathogenic fungi and to unlock
the stored nutrients in the soil and secure fertility naturally.

I have recently returned from Southern Oregon where I visited Mycorrhizal
Applications, located in Grants Pass,
Oregon. This company was founded
by scientist Dr. Mike Amaranthus who studied soil biology for over 20 years at Oregon State
University. This company believes
that a diverse and healthy web of soil microbes is the key to the future of
fertilizer. Thus, Mycorrhizal Applications distributes beneficial bacteria inoculants
and researches and produces significant quantities of specialty-fungal inoculants.
This is no fringe practice as is demonstrated by their international consumer
base.

In the Dryland Demonstration in Willits, CA,
we too are planning on using mycorrhizal inoculants to support our grain crop
as the fungi mineralize phosphorous, calcium, and iron provide and transport it
to the roots our wheat. These fungi additionally help the plant obtain and
retain water (crucial for dry farming). To apply these microbes we will coat
our grain seed with fungal spores and then broadcast the wheat into the soil.
This concept may be new to a lot of people and so the following blog is dedicated
to addressing:

"What Are Mycorrhizae?"

The word "mycorrhizae" literally
means "fungus-roots" and defines the close mutually beneficial
relationship between specialized soil fungi (mycorrhizal fungi) and plant
roots.

About 95% of the world’s land plants form the mycorrhizal
relationship in their native habitats. It is estimated that mycorrhizal fungal
filaments explore hundreds to thousands more soil volume compared to roots
alone.

Benefits include:

• Improved nutrient and water
  uptake
• Improved root growth
• Improved plant growth and
  yield
• Reduced transplant shock
• Reduced drought stress

In some cases, the fungi live inside the root (endo-mycorrhizal) and in other
cases it lives on the outside of the root (ecto-mycorrhizal). In both
instances, the organism is capable of providing nutrients and water necessary
for plant growth. In turn, the plant (via photosynthesis) provides necessary
sugars to sustain the growth of the fungi.

Follow
this link to read the FAQ
section from Mycorrhizal Applications where you will learn more about these
exciting creatures that are capable of unlocking the fertility of the soil naturally.

The Sebastopol Demonstration Energy Garden is located within the Sebastopol Sandy Loam series, which is described as a moderately fertile, well drained soil. Permeability is moderately slow in the subsoil, runoff is medium, and the hazard of erosion is moderate.

Soil texture is determined by the relative proportions of sand,
silt and clay and organic components that soil has. Sand is the largest particle, silt particles are smaller than
fine sand but can still be seen by the human eye, and clay particles are
microscopic.

Sandy soil—tends to be very
light and dries out swiftly. Water drains very quickly and makes the
soil easy to dig. It is the first to warm up in the sun.

Silt soil—retains moisture and feels slippery when wet. Retains nutrients better than sand but does not dry out as quickly.

Clay soil—a
very heavy soil, it holds moisture for long periods of time when wet
and dries hard as a brick. Clay soil retains nutrients and is very
fertile but is heavy, sticky and very hard to dig. It is the last to
warm up in the sun.

Loam soil—the ideal
soil texture, it is composed of sand, silt and clay. The ideal loam
soil contains 40% silt, 20% clay and 40% sand and organic matter. Loam
is a separate category because none of its compontents account for more
than 50%.
Loam soils are ideal for most plants, although many plants grow well in non-loan soils.

8/3/07 8/11/07

So as to test soil texture, we performed a comparitive test of samples from different parts of the garden.

A) Soil sample from path; untreated

B) Soil sample from bed; ammended with mango mulch

C) Sample of purchased compost; mango mulch ammendment

D) Sample of the compost developed on site.

We filled recylcled mason jars a quarter full with a portion of each sample, added water and a couple drops of biodegradable dish washing soap, and allowed them to settle for a week. Based on the thickness of each settled layer, we determined the proportions of sand, silt, and clay in our soil.

Using a basic LaMotte soil test kit and a soil auger, we tested each sample's pH, and the quantities of available nitrogen, phosphorous, and potassium.

The pH of our soils ranged from 6-8 and it appeared that the more organic materials that the soil contained, the more alkaline it was. The phosphorous content of our samples ranged from medium to high (75lb/acre-100+lb/acre).

The nitrogen content of our compost is tremendously high compared with the other three samples which could be expected because our chickens are allowed access to the piles. Aside from sample D, merely trace amount of nitrogen were present. The potassium content of our samples correlated with the proportion of organic marterial in the soil. The purchased mango mulch expressed the highest content, followed by the compost we have developed.

Nitrogen- stimulates leaf and stem growth. Nitrogen deficiency
causes reduced growth and pale yellowish green leaves. The
older leaves turn yellowish first since the nitrogen is readily moved
from the old leaves to the new growth. If the soil is cold and wet,
nitrogen in the soil is not as available to the plants. Excess nitrogen
may cause potassium deficiency.

Phosphorus-is important in the germination and growth of seeds, the
production of flowers and fruit, and the growth of roots.
Phosphorus deficiency causes reduced growth and small leaves that drop
early, starting with the oldest leaves. Leaf color is a dull,
bluish green that becomes purplish or bronzy. Leaf edges often turn
scorched brown. Excess phosphorus may cause potassium
deficiency.

Potassium- promotes general vigor, disease resistance and sturdy growth. Potassium deficiency causes stunted growth with
leaves close together. Starting with the older leaves, the leaf tips and edges turn scorched brown and leaf edges roll. Excess
potassium may cause calcium and magnesium deficiencies.

Using a disecting microscope at a magnification of 30x we analyzed the
contents of each sample, here looking for the amount of sand, clay,
silt, and organic materials. At this magnification the mycelium of
fungi was visible.

A. B. C. D.

A. Mostly sand w/ small amounts of silt

B. Finer sand particles and more silt than A.

C. Mostly organic materials. Mycorrhizae present among other mycelial growth.

D. More silt than A and B. Mycellial growth present as well as organic remnants.

Using a microscope at a magnification of 600x we analyzed the biology of each soil sample.

During July we have been working to produce
aerobic compost at the Willits Energy Farm. The compost project of July and
August is important because we are seeking to demonstrate a model of
sustainable farming practices that focus on soil fertility and includes an on-site
composting center. The challenge for this project is to produce 10 piles of
aerobic compost by sometime in August.

Currently, there are three piles that have reached high
temperatures of up to 150°F and are now entering their “cool down” phase where
they will sit until the fall. These piles have turned from a mixture of green
and yellow to a dark brown/black color. Three other piles are beginning to
decompose and will need to be turned a couple of more times before being
allowed to cure. We are going to let the piles sit for a couple of months so
that they can mature and allow the compost to develop a diverse set of micro
organisms including bacteria, fungi, protozoa, nematodes, and macro arthropods.

Quality compost is the substance and inoculum in which
a farmer can add organic matter to the soil and promote nutrient cycling. This is a natural
way in which a farmer can promote healthy plants, resist soil born
diseases, and ensure the fertility of the land for years to come. By producing
quality compost it is possible to eliminate the need for non-organic fertilizers
and pesticides because the soil will be very healthy and feed the plants in a
way that will help make them less susceptible to pests. It is useful to think
of pests as a way that nature “selects against” diseased and unhealthy plants. When
a plant is unhealthy it puts out a signal that insects tune-in to. Soon the bugs
come to eliminate the sick plant from the area, effectively selecting against
the weakest plant

Three Piles Under 50% Shade Cloth to Prevent Drying-Out

Compost Section Evolving to Accommodate More Piles

I checked material from one of the compost piles under my microscope today
to see which types of micro organisms were present. Since the pile was
previously hot and newly developed I noticed a good deal of bacteria, some
dormant protozoa, and some fungal spores. I knew that I would see bacteria, but
I wanted to set a "before" image in my mind about what was occurring
inside the pile. In a month I am curious to see whether or not there are more diverse microbes or if biology in the pile slows and becomes dormant.

This method, termed "direct count," is an alternative way of examining
soil and compost that and differs from the standard chemical analysis that most
people are accustomed to. The soil, roots, organic matter, and soil-based
microbes are all interconnected and work together to produce healthy plants and
living soil. The direct count method is useful because it provides a picture of
the life within the soil. We can use this "picture" to make
predictions about the nature and the health of the soil based upon the presence
or absence of certain organisms.

Below is a link to the article: Soil food web - opening the lid of the black
box. This was written by Bart Anderson and appeared on Energy Bulletin in late
2006. It is a great article that provides a synopsis about a truly sustainable way to maintain soil fertility and also describes the
importance of Dr. Ingham's work related to uncovering the interconnected world
of the "Soil Food Web".

This is the final part of a 3 blog set that discusses the importance of healthy soil, the need for compost at the Willits Energy Farm, and which factors lead to good compost. This blog will summarize our findings and report on the next step to addressing the needs of the site.

After examining the compost under the microscope, David, Jason, and I discussed the possibility of bringing some to the site. All of us agreed that we should probably not bring the compost made of grape pomace to the farm as it most likely contains alcohols and the presence of ciliates were a clear indicator of anaerobic conditions. Also the introduction of symphylums and springtails to the site was unthinkable. Balance is important when making compost, and a gigantic supply of one material (in this case grape pomace) does not make for a healthy end product. The gentleman who wanted to sell the compost made it clear that this was not his best batch and recommended that it might be better as mulch.

We also decided against the animal manure compost for one main reason-we were unsure of the temperatures of that the compost reached, and therefore, could not be sure that the weed seeds had been destroyed. The land at Brookside Elementary is gifted with a small weed bank. There is perennial grass that has been growing on the site, but otherwise we do not have any significant weeds in our beds. If we were to introduce this compost then we could run the risk of seeding the site with a problem that could eventually become a nightmare and more work.

After all this analysis we are back to the same problem of how to feed the soil and still intensively grow crops. Since compost is indeed a priority, I think that we must begin to treat it so. David and I fixed a broken stand pipe and we should now be able to water the compost piles that are located in the northwest corner of the site. We have amassed an abundance of biomass from clearing away the sod. Also, the warm spring weather has led to a burst of grass and clover growth along the perimeter of the fence. I can harvest the grass and clover with a push mower or a kama and use it as the nitrogen source for the compost piles. If we can keep on top of the compost situation we will end up with a bit of material to feed back into the soil after the spring vegetables.

I hope these blogs made it clear that it is important to consider the soil first as you begin or continue to grow food and energy crops. We must not simply mine the soil and we cannot extract its vitality without a cost. If we are going to grow crops intensively than we must be equally intensive about our compost processes and crop rotations. Compost is not a mere catch phrase as much as it is a means of emergency preparedness in relation to local food security. When Cuba faced an immediate scarcity of supplies resulting from the collapse of the Soviet Union, they lacked sufficient compost to grow crops on land that had been depleted through decades of practicing the conventional agricultural model that utilizes inorganic fertilizers, herbicides, and pesticides. A ready supply of compost will be a great resource for any community looking to turn to local agriculture as a response to an immediate and long-term need for food. It can help boost depleted lands and sustain the vitality of rich soil. I believe that we can do a lot for our communities and the environment if we can pursue agricultural practices that make the effort to grow and sustain healthy topsoil.

Welcome to Part 2 of the blog related to the importance of maintaining healthy soil at the Willits Energy Farm. If you followed the first blog, you will know that we will eventually need to do something about compost at the site. The soil is healthy and can sustain the crops that are being grown in it; however, to grow so intensively without the addition of compost is unsustainable. I felt that the addition compost would take the pressure off the land while we continued to work to establish the crops and the desired composting system. I consulted with David Drell and Jason Bradford and we thought that it might be a good idea, in this first year, to possibly import some compost if the source is not too far away. The plan to import soil is defiantly not how we want the site to operate in the long-term, yet, the health of the soil is a first priority and this is a consideration that we cannot afford to overlook, even if it means importing some compost.

There are multiple people offering “compost for sale”, however, one needs to be careful about the quality of compost that you are buying. Some stuff that is touted as “compost” is no better than mulch, and the processes in which the organic material was created may not have been aerobic or hot enough to kill weed seeds (150°F). If the organic material was composted anaerobically, it will contain natural alcohols that can turn a plant to slime by dissolving portions of the cell walls. Finally, anaerobic compost will lack fungi and the compost will thus lack the diversity need for a healthy soil food web. If the material has the potential of causing harm instead of helping the situation we will not bring it to the site.

David and I decided to visit a farm site that as been know for creating quality compost and take samples to view under the microscope. By talking with the person who makes the compost and by looking at the types of microbes inside it we can make a fairly good assessment of whether or not we want it on the site. When we arrived to the farm there were two different compost piles to choose from. One of the compost piles had been created using grape pomace from a nearby vineyard that had been mixed with straw bedding and spoiled hay. There were earthworms in that compost and also a great deal of little white bugs. Some of the bugs were spring tails and others were symphylums. These symphylums are particularly nasty if they do not have a good deal of fungal biomass to eat. If there is no fungi the symphylums will eat plant roots!

The other pile of compost was made in windrows that had not been turned for 8-9 months. It was composed of 70% horse manure, 25% made of goat droppings, and 5% chicken manure. It looked very nice and had an earthy smell, no visible bugs.

After getting the samples home I examined them under the microscope.

Grape Pomace Compost:

The grape pomace had a diversity of organisms. Lots of bacteria and large dark strands of fungal hyphae were present (large dark fungal strands are a good thing). Unfortunately, there seemed to be a large number of ciliates, which are protozoa that thrive in anaerobic conditions. I also noticed bacterial feeding nematodes (small round worms) that feed high on the soil food web. While the fungal strands looked promising, the presence of symphylums and springtails coupled with the knowledge that some of the material might have been fermented into natural alcohols made this compost into something that we did not want to bring to the site at Brookside Elementary.

Animal Manure Compost:

The animal manure compost was bacterially dominated and had beneficial protozoa in it. Beneficial protozoa include testate amoeba and flagellates. These protozoa are important because they eat the bacteria and help cycle the nitrogen contained in the bacteria into plant available forms. I noticed some large, dark fungal strands; however this compost did not have the fungal biomass that the grape pomace compost. I did not notice any nematodes. Out of the two compost samples, I felt that this one was the best.

Grape Pomace Compost

Grape Pomace Compost (Notice it is purple)

Manure-Based Compost

Example of a Bacterial Feeding Neamatode (The Spots Toward the Tail Are Bacteria)

Example of a Fungal Strand with a Red Spore

Example of Two Cilliates (Protazoa). They Are Feeding On Bacteria

When working the land to grow food and energy crops our first priority and greatest resource is the soil. It has been said if humans take care of the soil then the sun and water will care for the plants. At the Willits Energy Farm we are developing a mini-farm template that factors in crop rotation systems, bed preparation, and a multi-faceted compost center designed to preserve and grow soil. As is evident by the abundance of earthworms that fill almost every scoop of soil, the site at Brookside Elementary has a nutrient rich soil high in organic matter. A soil analysis from December 2005 indicates that the percentage organic matter is 6% and there exists large reserves of exchangeable nutrients.

The same report shows that the soil is rich in microbial life including fungi, protozoa, and especially bacteria. Micro organisms are important aspect of the soil because they participate in the process of nutrient cycling and nutrient retention. Nutrient cycling is the conversion of organic matter and the exchangeable nutrients within the soil into plant available “foods”. Cycling occurs when bacteria and fungi decompose and metabolize organic matter in the soil. These microbes store the nutrients in their bodies (retention) and are themselves eaten in the processes and interactions within the natural food web of the soil. When a diverse set of microbes are interacting in the soil the nutrients are less susceptible to leeching out and the fungal threads and bacterial glues help form soil aggregates that resist compaction. As you might expect, healthy compost is a primary inoculum soil based micro organisms.

Given what has been said about the value of healthy soil, we have begun to plant out and seed spring annuals. These vegetables are transplanted in closely spaced sets and seeded densely in order to grow the greatest amount of food in the smallest space possible. On marginal soil this sort of approach may not produce desired yields as the plants struggle to find the nutrients in land that has been depleted or lacks the nutrient cycling provided by diverse microbial life. Although we have excellent soil to begin this project with we need to be careful not to deplete the reserves that have been stored up through the years. The Grow Biointensive method that we are pattering some of our crop spacing after admits that in order to produce large crops yields in a small space you will need to replenish the land and soil to make up for the nutrients used in the processes of growth. It is clear that we will need to amend the soil with compost after each section of annuals is finished.

Example of Intensive Planting of Onions and Lettuce

Intensive Planting of Peas, Beets, Cabbage, and Swiss Chard

I am fortunate to spend the week of February 5^th
through the 11^th taking classes at the Sustainable Studies Institute
with Dr. Elaine Ingham. The institute is based in the heart of Oregon’s agricultural research center Corvallis, Oregon. Dr. Ingham is a global pioneer in the field
of soil biology and her research has lead to possibly the most advanced studies
and understanding of compost and compost tea in the world. Dr. Ingham has been
involved in chemistry and biological research for many years and brings a
wealth of experience and knowledge to bear on topics related to the
interactions of the soil biology with trees and plants, compost and compost
tea, the recuperation of marginal lands through an understanding of the soil
biology, and the suppression of pests and diseases though the use of activated
compost tea.

In this 6 day workshop there will be a three day discussion
to the soil food web, a day on composting, a day on compost tea technology, and
a day of microscope methods. I look forward to gaining the ability to begin to
make assessments of the biology of soil and compost with the use of my new
microscope. This will help me decided which organisms may need to be selected
for as we prepare a particular plot of land as I consult with groups and community
members in hopes of gaining a better understanding of the needs of the land.

I hope to come from the class with a deeper understanding of
the interactions within the soil and to find a way of maintaining the
consistent reliable production of food that does not rely on the petrochemical
industry’s inorganic fertilizers. In a limited petroleum and natural gas
situation the use of these fertilizers will be cost prohibitive, not to mention
inherently destructive of the environment. I believe that the ability to make
quality compost and provide information about compost teas will be invaluable
in a post-petroleum context. Finally, I expect to be able to understand better
the tea that I learned about in Ecuador
and demonstrated at the Energy Farm in Vancouver
BC in the month of October.

Check out the Sustainable Studies Institute and Soil Foodweb
Inc. here to learn more:

http://soilfoodweb.com/

http://www.sustainablestudies.org/