Thursday, March 10, 2011

Farmer's Perspective - Soil Values

[Soil transect, via Nature and Properties of

We set aside the most stunning natural landscapes as state or natural parks, and designate urbanized areas of particular charm and significance as historical preservation districts. But as is pointed out in the post below by Pablito, our guest blogger and farm manager at Terra Firma Farms, the most valuable agricultural soils are up for grabs. The American Farmland Trust estimates that the U.S. loses one acre per minute of farmland to development, which is especially damning when you consider the planned obsolecene of the shopping malls, auto dealers and office parks springing up on that land. Can we imagine farmland parks, set aside on the merit of their soils, or soil preservation zones for prime farmlands? It would require public education for sure, as the maxim 'out of sight, out of mind' certainly applies to soil in the popular imagination. It might require an expediture of public funds, which could be offset by creating public access trails within or alongside these farmlands. Rather than bemoaning the loss of farmland, it would mean planners would use the soil maps to actively shape development districts. It's definitely an idea worth considering - read more from Pablito below:

   Have you ever driven through a rural area,and wondered why some land is planted in vineyards, some in orchards, other in vegetables or hay, while still other has livestock grazing on it?
   There are many reasons why one farmer might grow, say, lettuce, while her neighbor grows, say almonds.  Many times it boils down to tradition, as for most farmers agriculture is still a multi-generational business.  They grow what their parents grew, especially if their parents planted an orchard or invested in specific processing equipment for a certain crop.Climate and microclimates also play a huge role in what farmers grow. And of course, the availability of irrigation water plays a huge role.  If a piece of farmland is located along an irrigation canal, or has a groundwater well with a pump, much more can be grown on it than the same piece of land without water.
  All that said, the single most important factor in what crops are grown on a piece of land is the soil type.  There are hundreds of types of soil in California alone, each and every one classified by a universal system and mapped by the Soil Conservation Service of the USDA (now the NRCS).  You can look at a map of all the soils in your county (or any other county), and a detailed description and evaluation of each of them, online.
  Not all soils are good for farming.  There are soils that are nearly perfect for farming just about anything, soils that are more limited, and those that won't grow much at all.  "Good soils" are a balance of different particles (sand, silt, and clay) as well as organic matter.  Too much of any one of those will limit what can be grown in it.  Too many rocks and gravel in soil also limit its usefulness for agriculture.  Another important element is the depth of the soil and what lies under it.
    The better the soil is for farming, the more food it produces using the least fertilizer, water,  fuel and pesticides.  This is why most environmental groups recognize preservation of good farmland as a key tenet of ecological sustainability.
   Something else many Californians don't know:  our state's irrigation system was designed from the start to bring water to the areas with the best soils for farming.  Since reservoirs tend to be in the mountains and good farmland in valleys, this was a natural fit -- especially since very little energy is needed to make water run downhill.
    It's true that throughout history, civilizations have survived in areas without much good soil by developing crops suited to their landscapes.  Olives and grapes thrived in the rocky Mediterrean hillsides of ancient Italy and Greece, for example.  But to sustain their populations, both civilizations ended up conquering other nations with better farmland.  Rice is the only major staple crop that has been bred to grow on land that is otherwise useless for farming -- poorly drained soils that flood annually.
    California's valuable agricultural soils are not protected by any state or federal laws the way some of its unique natural habitats are.  Local zoning laws in agricultural areas often give lip service to preserving the best land, but even  a quick look at the NRCS soil maps reveals the truth:  most new development in California in the past twenty years has been built on good farmland.  The only state law aimed at protecting farmland is a tax credit called the Williamson Act that rewards landowners for keeping their land in agriculture.  Unfortunately, the Act has repeatedly been a target of budget cutters in the assembly and governors office, dismissed as a tax break for wealthy landowners.
     Eventually, tax credits alone will not be enough to stop the destruction of critical farmland.  Human populations will keep growing and good soil will be paved over until rising food prices force a shift in the economic and political reality that currently undervalues farmland.
(excerpted from TerraFirma Farm newsletter, March 2, 2011)