Farmland LP

Or, What You See from Space (and What You Don’t)

Part 2 of 2

In the first post of this series, I explained how rotational grazing quickly builds soil organic matter (SOM).  In this second part I discuss the importance of SOM for organic farming.

Mineralization for Organic Farming

Mineralization is the process by which SOM, which consists of large and complex organic molecules, breaks down or decomposes into simpler, i.e., mineral, forms.  These simpler forms are called Plant Available Nutrients, or PAN, and standard soil tests measure PAN levels of various minerals and nutrients.  In conventional agriculture fertilizer is applied to compensate for any measured deficits.  In organic farming systems we can make up for deficits with approved inputs, such as pulverized rocks high in certain minerals and animal manures, but we also rely more on the mineralization process for release of nutrients from the soil organic matter.  In the agronomic system used by Farmland LP, deep-rooted, perennial plants and associated fungi are sown to both increase SOM and access minerals from well below the soil surface and bring them up to enrich the topsoil.

To an organic farmer this means one of the most critical parts of a soil test is the level of organic matter.  Prior to the wide-spread availability of synthetic nitrogen and other fertilizers, farmers essentially used accumulated stores of SOM to grow crops.  The following is a quote and graph from the 1938 USDA Yearbook and was written by University of Missouri professor William Albrecht:

In addition to carrying nitrogen, the nutrient demanded in largest amount by plants, soil organic matter either supplies a major portion of the mineral elements from its own composition, or it functions to move them out of their insoluble, useless forms in the rock minerals into active forms within the colloidal clay. Organic matter itself is predominantly of a colloidal form resembling that of clay, which is the main chemically active fraction of the soil. But it is about five times as effective as the clay in nutrient exchanges. Nitrogen, as the largest single item in plant growth, has been found to control crop-production levels, so that in the Corn Belt crop yields roughly parallel the content of organic matter in the soil (184). On a Missouri soil with less nitrogen than that corresponding to 2 percent of organic matter (40,000 pounds of organic matter per acre of plowed surface soil) an average yield of 20 bushels of corn per acre can hardly be expected. For yields approaching 40 bushels, roughly double the amount of organic matter is required. With declining organic matter go declining corn yields and therefore lower earnings on the farmers investment. Thus the stock of organic matter in the soil, particularly as measured by nitrogen, is a rough index of land value when applied to soils under comparable conditions. According to studies in Missouri, for example, the lower the content of organic matter of upland soil, the lower the average market value of the land.

Original caption:  Decrease of organic-matter content in a fallow, untreated soil in contrast to the gain in soil treated with 2 1/2 tons of red clover annually, representing over 500 pounds annual increase in organic matter per acre.

If you have the time and interest, the entire Albrecht article is very interesting as it gives an historic perspective from one of the most important soil scientists of the 20^th century.  Many of his views and insights are still valid today.

SOM values thus have very practical applications, including planning for fertilizer needs.  The linked chart (from an agronomy handbook sent to me by soil testing company Midwest Laboratories, Inc.) shows the relationship between SOM and nitrogen availability.  Here’s the math behind that chart.

Stabilized SOM has a ratio of carbon to nitrogen atoms of 12:1.  As explained by Albrecht, this nitrogen becomes available to plants as soil organic molecules are broken into parts.  The top 6 inches of soil is typically considered to have a mass of 2 million pounds, and so 5% SOM is 100,000 lbs.  The nitrogen is usually about 5-6% of the SOM mass (other parts include C, P, K, S, etc.) and 6% of 100,000 lbs is 6000 lbs of N.  If 2% of this N mineralizes, then 120 lbs is available for plant growth, which is a good amount for most crop types.  The nitrogen has an economic value in that it is a form of fertilizer that farmers don’t need to purchase, giving us an additional source of value from the diverse pasture aside from just the revenue from grazing ruminants.

What Farmland LP does during the conversion of conventional farmland to certified organic farmland is place most of our acres into perennial pasture and/or forage crops that are rich in legumes.  These perennial crops are growing year-round, not just for a season or two like an annual plant, and become very effective givers of organic matter to the soil.  As I’ve explained before and touched upon in the first post in this series, the livestock actually increase plant productivity by grazing enough to foster renewed plant growth 5-7 times per year while depositing manures that activate the soil microbes and speed the nutrient cycle.  Rotational grazing not only leads to 25-50% greater plant productivity than set stocking, but results in perhaps 10 tons of dead organic matter added yearly:  on the surface as manure, trampled leaves and stems, and via the sloughing of roots.  Some fraction of this, about 15-20%, is converted to SOM and thereby enhancing the value of the farmland we manage.

Measuring SOM

We measure soil organic matter in two ways.  The first is through standard agronomic sampling, which is done every 2-3 years and on a broad scale using “Smart Sampling” guidelines to help us plan for fertility inputs and to see how our soils are doing from field to field.  This sampling method gives us a picture of SOM over a wide area, but a shallow depth (6-8”).  For this kind of testing we may sample at a scale of one per every 2-6 acres at a cost of about $20 per sample.  A farm service company manages this sampling, gathering the soil at specific locations that are predetermined with geo-coordinates and so are moderately replicable.  Below is an image of the mapped SOM for our Wattenpaugh Farm as an example.  The area shown is about 90 acres.

The second measurement method is much more detailed, and includes soil properties that should change with SOM, such as bulk density and infiltration.  We select a “representative” site at each property we manage.  A non-profit called Soil Carbon Coalition, run by Peter Donovan, does the sampling work using a protocol meant to be accurate and repeatable.  The goal is to measure change at a specific location, not give us a broad view of the farm and its various fields, and since it is measuring something that changes rather slowly the intention is to re-sample every 2-3 years also.

To see the Soil Carbon Coalition reports for our farms go to this url: and in the “Plot report for:” box type in “FR” for Fern Rd Farm and “FL” for our other properties in the area.

What You Don’t See

We love that Google Earth can take pretty pictures of our farmland, but there is so much happening beneath the surface that a satellite just can’t see, at least not directly.  But as good soil practices spread to cover thousands and millions of acres, it is our hope that Google Earth will be able to see more lush landscapes and healthier waters.

Not only are we invisibly building healthier soil beneath the ground, but we are also invisibly restoring balance to our planet’s atmosphere by creating SOM from the air we breathe.  The nitrogen in our organic system comes from the 78% of the atmosphere that is nitrogen, which is plentiful and free.  The carbon of SOM comes from the carbon dioxide in the atmosphere, which at over 390 parts per million is too high and already changing our climate.  Given the high price of fertilizers made from fossil fuels, and the rising costs to society of the pollution caused by their use, we believe in the wisdom of letting ruminants eat pasture while building wealth and health beneath their hooves.

Or, What You See from Space (and What You Don’t)

Part 1 of 2

A key to the success of Farmland LP is having great livestock managers to make the most out of our high quality pasture.  In Oregon, Mac Stewart of Vitality Farms runs sheep on over 900 acres of Farmland LP property.  And now you can see his work from space.

New Google Earth Imagery

Google Earth recently updated the satellite imagery covering our properties in Oregon.  The resolution is so good that in the image below you can see individual sheep grazing in a paddock.

Our western property boundary is shown with a blue line.  A wheel line (for irrigation) is adjacent to the property line.  Off-white oval specs are the sheep.  They are in a paddock made by temporary electric fencing that is about 160 ft from north to south and 820 ft from west to east, about 3 acres.

To the south of the current paddock is the previous paddock.  It is less green because much of the vegetation was eaten by the flock a couple of days before.  The dark green paddock to the north was set up just prior to when this image was captured.  The sheep will be moved there later in the day.

Shepherd Mac Stewart changes the length of stay for the sheep based upon the size of the flock, the pasture quality and growth rate, the weather, and many more factors—all to encourage the pasture and lambs to grow steadily.  In two separate posts, I’ll explain a number of key concepts in pasture and flock management (Part 1) and how good management leads to an increase in the quality and value of the soil (Part 2).

Pasture Diversity and Productivity

Some people think pasture is just grass on poor quality ground, but great farmland can also be extraordinary pasture in terms of productivity and environmental and economic yields.  There is an entire science behind it.

As a simple example, our custom blended pasture mixes include a lot of plant diversity with the goal of evening out the productivity of the stand over the year, since the sheep need food for 365 days.  For our Oregon properties and their associated climate, the grasses, such as tall fescue, orchard grass and perennial rye grass, do best in the cool months.  To take advantage of growth over the summer we also sow forbs that like it warm, such as chicory and plantain.  Clover diversity, including red, white and alsike, also extends the season of legume productivity.  The chart below (from this University of Arkansas web site) shows how the growth of different forage classes is distributed during the year.  The growth curves in Oregon are not exactly the same as what is shown below, but the concept applies everywhere—add diversity to enhance and spread-out the productivity.

The picture below shows the same location as the Google Earth image above, except viewed from the ground (you can see the lone Oregon Ash tree in the background).  It was taken August 15^th, about a month after the Google Earth image above (July 9^th), and you can see the plant diversity in our pasture and that it is ready to graze again.  Healthy pasture makes great lamb.

Payse Smith, a student at Oregon State University, is shown above.  He is taking standardized samples of the field to determine the standing biomass.  We use this information to study the growth and recovery rates of our pasture, which ultimately determines the optimal number of animals for the field.  I’ll explain how this works with some illustrative numbers to keep it simple.

Rotational Grazing by the Numbers

A flock of sheep eats about 5% of its body mass in dry matter each day.  If we have 1000 sheep with an average weight of 90 lbs, the total biomass of sheep in the flock is 90,000 lbs.  Multiply 90,000 lbs of sheep by 5% to get 4500 lbs of dry matter per day required for the flock.  Now we don’t want the sheep to eat ALL the vegetation in the paddock, and a good rule of thumb is to only consume half the total biomass so that the pasture has leaves available for a fast recovery.  I explained this in a post from two years ago, and the relevant portion is repeated here:

Pasture experts talk about the S-curve.  This refers to changes in the rate of growth of the stand of plants.  When plants are very small, they put on only a small amount of biomass per time.  But at a certain size, the amount they add each day increases rapidly.  Of course any exponential rate of growth must end, and so growth slows and halts as the plants reach maturity.  S-curves are common in all biological growth systems.  What good pasture management does is keep animals eating much of the pasture before it reaches the mature, no growth stage, but not so much that the pasture has a very long recovery time because the plants have been eaten back to the slow-growth portion of the S-curve.

Back to our example of the flock of 1000 sheep…If the flock needs to eat 4500 lbs of dry matter in a day we need a paddock with around twice this amount, or 9000 lbs.  Since each acre has a standing dry biomass of about 3000 lbs when it’s at the top of Stage 2 in the S-curve, a 3 acre paddock will comfortably feed those 1000 sheep for a day.

This is good forage management and gives us the ability to grow high quality lambs as quickly as possible during the main months of productivity, which here in Oregon is April through October.  But it also does something else very important to the soil.  As the plants grow, are eaten just right, and regrow again—a cycle that repeats up to seven times per year—the soil organic matter (SOM) increases.  Instead of buying in tons of compost per acre, at a cost of many hundreds of dollars, our pasture produces tons of soil organic matter per acre.  SOM does many things to improve soil quality, including increasing water holding capacity and improving soil tilth, and, as I’ll explain in Part 2 of this post, it stores nutrients that become available to plant roots through a transformation termed mineralization.  So even though you can’t see it from space, what is happening below ground may be more beautiful than what is happening above.