of good soil management deals with air, water and carbon digestion (physics and biology), is soil testing really about fertil- ity? The intention is to change soil physics and improve the environment for soil biology. After more than twenty years of soil testing, tens of thou- sands of soil tests on hundreds of sites, I have never seen the process fail if the turf manager sticks to the basics. I have, however, repeatedly been told that it cannot work, “you can’t change soils physically by changing soils chemically”, “there is no research to prove this”, “an acre inch is two mil- lion pounds of soil much too much to change…” The truth is you can change soils physi- cally by manipulating the soil chemically and you better if your soils are out of balance and you hope to produce bet- ter turf with fewer inputs. We are not changing clay to sand or sand to silt and we are not concerned about the entire two million pounds of soil in the acre inch, we are only con- cerned about the four thousand pounds or so that make up the nutrient profile particularly cal- cium, magnesium and potassi- um that affect soil flocculation which impacts soil biology and that we can change. What we are really focused on is Biological Soil Management. According to the working models presented by Dr. F OR OVER TWENTY YEARS I have been staring at soil tests, writing reports and recommen- dations. And for over twenty years I have seen, sports turf managers, and golf course superin- tendents make changes to their properties. Clearly they have produced better turf but more importantly they have made changes to their soil profile. They have improved drainage, strengthened rooting, increased plant recovery and they reduced fertility inputs. Why? Because they have soil tested and their soil testing programs have helped them to discover that improving the physical structure and biological profile of the soil is the precursor to good soil and plant fertility. The four basics of good soil management are: Air Management, Water Management, Digestion Management and finally Nutrient Management, in that order. Air space in the soil allows for good water movement, without air in the soil roots will not survive and beneficial soil micro-organisms will not prolif- erate. With too much water an anaerobic condition will prevail and both roots and microbes will die off. With good air and water movement through the soil profile you will create the environment where benefi- cial soil microbes can freely multiply and in the process carbon is digested down to humus — the ultimate break down of organic matter in the soil. This humus is then used as a microbial food source to generate even more biological activity. It is the back bone of the carbon to nitrogen cycle in the soil, producing free and needed nitrogen to the plant without all the side effects of synthetic applications. If and only if the environment for microbial digestion is present in the soil will nutrient mobility take place. Microbes “eat at the table first” and all nutrient mobility from the soil is done through microbial degradation. A good soil testing protocol allows the turf manager to manipulate the soil physically, by balancing basic cations and relaxing soil particles just enough to allow better air and water movement through the soil profile. This builds a better environment for soil micro-organisms to do their job of digesting carbon, releasing nutrients into the root zone and providing buffers for water, temperature and pathogen attack. So, if 75% 16 SportsTurf | April 2010 www.sportsturfonline.com SOIL TESTING IS NOT ABOUT FERTILITY At least not exclusively! FieldScience | By Joel Simmons After more than twenty years of soil testing, tens of thousands of soil tests on hundreds of sites, I have never seen the process fail if the turf manager sticks to the basics. Soil image courtesy of istockphoto.com
Transcript
of good soil management dealswith air, water and carbondigestion (physics and biology),is soil testing really about fertil-ity?
The intention is to changesoil physics and improve theenvironment for soil biology.After more than twenty yearsof soil testing, tens of thou-sands of soil tests on hundredsof sites, I have never seen theprocess fail if the turf managersticks to the basics. I have,however, repeatedly been toldthat it cannot work, “you can’tchange soils physically bychanging soils chemically”,“there is no research to provethis”, “an acre inch is two mil-lion pounds of soil much toomuch to change…” The truthis you can change soils physi-cally by manipulating the soilchemically and you better ifyour soils are out of balanceand you hope to produce bet-ter turf with fewer inputs. Weare not changing clay to sandor sand to silt and we are notconcerned about the entire twomillion pounds of soil in theacre inch, we are only con-cerned about the four thousandpounds or so that make up thenutrient profile particularly cal-cium, magnesium and potassi-um that affect soil flocculationwhich impacts soil biology andthat we can change. What weare really focused on isBiological Soil Management.
According to the workingmodels presented by Dr.
FOR OVER TWENTY YEARS I have been staring at soil tests, writing reports and recommen-dations. And for over twenty years I have seen, sports turf managers, and golf course superin-tendents make changes to their properties. Clearly they have produced better turf but moreimportantly they have made changes to their soil profile. They have improved drainage,strengthened rooting, increased plant recovery and they reduced fertility inputs. Why?
Because they have soil tested and their soil testing programs have helped them to discover that improvingthe physical structure and biological profile of the soil is the precursor to good soil and plant fertility.
The four basics of good soil management are: Air Management, Water Management, DigestionManagement and finally Nutrient Management, in that order. Air space in the soil allows for good watermovement, without air in the soil roots will not survive and beneficial soil micro-organisms will not prolif-erate. With too much water an anaerobic condition will prevail and both roots and microbes will die off.With good air and water movement through the soil profile you will create the environment where benefi-cial soil microbes can freely multiply and in the process carbon is digested down to humus — the ultimatebreak down of organic matter in the soil. This humus is then used as a microbial food source to generateeven more biological activity. It is the back bone of the carbon to nitrogen cycle in the soil, producing freeand needed nitrogen to the plant without all the side effects of synthetic applications. If and only if theenvironment for microbial digestion is present in the soil will nutrient mobility take place. Microbes “eatat the table first” and all nutrient mobility from the soil is done through microbial degradation. A goodsoil testing protocol allows the turf manager to manipulate the soil physically, by balancing basic cationsand relaxing soil particles just enough to allow better air and water movement through the soil profile.This builds a better environment for soil micro-organisms to do their job of digesting carbon, releasingnutrients into the root zone and providing buffers for water, temperature and pathogen attack. So, if 75%
16 SportsTurf | April 2010 www.sportsturfonline.com
SOIL TESTING IS NOT ABOUT FERTILITYAt least not exclusively!
FieldScience | By Joel Simmons
After more than twenty years of soil testing, tens ofthousands of soil tests on hundreds of sites, I have neverseen the process fail if the turf manager sticks to the basics.
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18 SportsTurf | January 2010 www.sportsturfonline.com
FieldScience
18 SportsTurf | April 2010
Albrecht at the University ofMissouri, and Dr. Bear atRutgers University we arelooking to balance the basicsoil cations and striving for aprofile that presents roughly68% calcium, 12% magne-sium, 5% potassium, 2 %sodium, 3% trace elementsand 10% hydrogen. When acolloidal soil moves to thesepercentages the soil physicallyworks better. Air and watermove through the profilemore efficiently building anenvironment where soil biolo-gy explodes and the nitrogencycle increases. In this modelif we can achieve 10% hydro-gen we will always have a pHof 6.3 which is the point atwhich we find maximumpotential nutrient mobilityacross the entire nutrientboard. These percentages arefound in the base saturationsection of a complete base sat-uration soil test and can easilybe manipulated by addingwhat is deficient and knock-ing off what is excessive.Unfortunately, not all soiltests show a complete basesaturation where all six cationgroups are present, calcium,magnesium, potassium, traceelements, sodium and hydro-gen. Too often a soil testinglaboratory will show a limitedspectrum of soil cations orthey will add up to somethingmore that 100% which is nota true base saturation andmakes building a quality rec-ommendation all most impos-sible.
The following base satura-tion was found on a soil testof a sports turf client: 35%Ca; 45% Mg; 2% K; 5% Na;3% traces and 10% hydrogen.He was not able to aerify thesoil because it was too hard
20 SportsTurf | April 2010 www.sportsturfonline.com
FieldScience
and the metal tines of the aeri-fier would not penetrate thesoil. When it rained the soilwould not drain for days, hehad very poor rooting, seedgermination was weak and hehad to apply over 8 pounds ofsynthetic nitrogen per 1000square feet to the site each yearsimply to maintain color.When I asked how his soil washe responded by saying “it’snot my soil, I tested it and thepH was 6.3!” He had over a1700 pound deficiency in cal-cium, a thousand pound excessof magnesium, low potassiumand high sodium. I recom-mended three applications ofhigh calcium limestone at arate of one ton per acre, sepa-rated by a few months, alongwith a lot of potassium sulfate.After the second application oflime I called him and asked ifhe was able to aerify the prop-erty and he reported that hecould not. So I asked him ifhe had seen any difference andhe did say that he thought theyhad reformulated his fertilizerbecause it was working a lotbetter. With better soil biolo-gy fertilizer will work better!One year later he called andtold me that he had run hisaerifier over this site and didnot break a single tine, whichwas uncommon prior to mak-ing the soil adjustments, so heran the machine off the treatedarea to an adjacent soil thatwas not treated and as soon ashe hit that soil he broke themachine into pieces! Hereduced his nitrogen inputsdown to around two poundsper 1000 square feet per year,drainage was no longer a prob-lem, rooting was strong anddeep, recovery was excellentand seed germination when heneeded it was very good.
SportsTurf 21www.stma.org
When staring at as many soil tests as I doit sometimes becomes hard to see the forestthrough the trees but a client once told methat when the light bulb finally went off forhim was when he realized that base satura-tion was always 100%, no more and no less.If a soil test shows more or less than 100%base saturation it is not a true base saturationtest which is the key here. Understandingthat it is always 100% makes it easy to seethat if something is high it can be exchanged(cation exchange capacity) by replacing itwith what is low. In the previous examplemagnesium was driving the soil and calciumwas low so by adding the proper amountand type of calcium we were able to drive offthe magnesium which was tightening the soiland affecting soil biology.
Base saturation is only one of many toolsthat we use to manage soil profiles and onsome soils it is not as strong a tool, such aslow CEC sand based soils, but the tool canstill give us direction. On these sites the suf-ficiency levels of nutrients is clearly our firstfocus. I have become a big fan of the watersoluble paste extract test to give me evenmore information and help me answer somequestions that may not be easy to answersimply by reviewing the standard soil tests. Iuse Logan Labs (www.loganlabs.com) for mylab work but there a number of good labsproducing complete base saturation soil tests.A complete base saturation soil test willnever lie to you it may tell you that sodiumis driving the soil like out west or calcium onthe calcareous soils of the mid west or evenaluminum like in some of the gumbo soilsdown south. A good soil testing protocolwill give you the map and directions on howto affect physics which will affect soil biolo-gy. Oh and by the way all of this improvesnutrient mobility! ■
Joel Simmons is the President ofEarthWorks Natural Organic Products andSoil First consulting and teaches the Soil FirstAcademy all across North America. He holds aMasters Degree from Penn State Universityand is a former Penn State County ExtensionAgent and Instructor of Soils at RutgersUniversity. He may be reached in front of hiscomputer at [email protected] most likelyworking on yet another client’s soil test.
