Sweet and Sour Dirt A little understanding of

Sweet and Sour Dirt A little understanding of p. H to help you use biochar better Contains animation. View in Slide Show mode

Soils Have Flavors! It’s possible to taste a difference between different types of soil • Acidic soils taste sour We don’t recommend this! • Basic (alkaline) soils taste slightly sweet • The flavor of a soil affects… Mike Lieberman of Urban. Organic. Gardener. com – How well different plants grow – What kind of microbes thrive in the soil – How well the solid holds on to various minerals • We talk about soil’s “flavor” as p. H ~2~

What Exactly is p. H? power of… p. H …hydrogen ions (H+)… …in water • Water allows some hydrogen ions to escape from their molecules • p. H tells the concentration of H+ in the solution • p. H is a logarithmic (not linear) scale compare waittehr w distilled 0 1 2 etc. 3 more acidic neutral more basic 6 4 5 7 8 9 10 10 X 100 X 1, 000 X 100, 000 X Concentration of H+ ~3~ 1/ 11 12 13 10 1/ 100 1/ 1, 000 1/ 100, 000 vs. distilled water etc. 14

Finding the p. H (without tasting) Litmus paper colors shows p. H Hydrangeas’ colors reflect soil p. H Do-it-yourself home test kits Meters read p. H directly 4

Strength of p. H • • • Acids release H+ Bases suck up H+ Acids and bases neutralize each other Biochar is basic (alkaline). It can neutralize acidic soil. ~5~

Soil’s Natural p. H Varies Light rainfall & prairie neutral soils Heavy rainfall & forest acidic soils Cultivated & developed soils often differ from native soils Natural limestone bedrock alkaline soils Drought & desert alkaline soils Soil p. H Strongly Acidic Mildly Acidic Neutral Mildly Alkaline But soils can also differ from one yard to another. 6

Different Plants Like Different Soils blueberry lilac ash hydrangea azalea geranium white birch eucalyptus pomegranate ~7~

Soil Ecology and p. H ity n u m m o C g n i Soil is a Liv Resident What it does Effect of p. H Fungi • Decompose dead plants, animals, and Prefer slightly acidic p. H bacteria into nutritious molecules • Some live in plant roots to help plants take up nutrients Bacteria • Decompose dead plants, animals, and Prefer slightly alkaline p. H fungi into living molecules • Exude nutritious molecules • Become food for higher organisms Insects & worms • Excrete plant fertilizer • Open spaces in soil to let in air and water to support soil life • Become food for bacteria and fungi Supports Plants ~8~ • Don’t like extreme p. H • Worms avoid acid p. H Supports Animals Unbalanced p. H upsets the whole community

Soils and Mineral Availability • Plants need many minerals to thrive • Plant roots only absorb minerals dissolved in water. • If solution is too acidic or alkaline, H+ chemistry locks up some nutrients. Examples: p. H < 6. 00 Mg deficiency Mineral availability in solution Nitrogen Phosphorus Potassium Sulfur Calcium Magnesium Iron Manganese Boron Copper and Zinc p. H Fe, Zn, Ma deficiency ~9~ Source: Colorado State Extension CMG, Garden. Notes #222 est b s i H p ral t u e n r a Ne als r e n i m t for mos

Most Plants Like Near-Neutral Soils Best for minerals Best for fungi Best for bacteria w o r g s t n a Most pl. e g n a r in this ~10~

Neutralizing Because p. H scale is not linear, neutralizing different strengths takes very different quantities Equal distances from neutral, use equal concentrations 0 1 2 3 acid = base more acidic neutral more basic 6 4 5 7 8 9 10 11 12 13 acid = base 14 acid = base One p. H number further from neutral, use 1/10 th Two p. H numbers further from neutral, as much of the stronger use 1/100 th as much of the stronger ~11~

How to Modify Soil p. H First – Test Your Soil !!!!! Adding organic matter to the soil makes both acid and alkaline soils more neutral. Lower Soil p. H (improve alkaline soil) Raise Soil p. H (improve acid soils) Add one of following: Add one of the following: Granular sulfur slow acting Aluminum & Iron Sulfate faster need a lot Acidifying fertilizer Doesn’t work well for p. H > 7. 5 May contain a large amount of calcium carbonate Ground limestone lasts a long time Hydrated Lime works quickly easy to over-do Wood Ashes fast-acting a little goes a long way ***** ALWAYS FOLLOW DIRECTIONS **** ~12~

Biochar and p. H • Biochar is usually alkaline • Biochar p. H depends on the pyrolysis temperature biochar neutralizes Biocha r’s neu tralizi power ng diminis after hes a few years. acidic soil typical p. H range typical formation temperature range NOTE: ash created by pyrolysis is strongly alkaline (p. H 12 -13) ~13~

Using Biochar to Change Soil p. H alkaline First – Test • If your soil is already alkaline, Your Soil !!!!! don’t use biochar! • Because biochar is a pretty strong base , use it sparingly 2% e lum o v by er p tion a c i l app • To keep p. H moderate, add small amounts of biochar every few years, not all at once. • If your soil is strongly acidic (<ph 5), you can mix a small amount of ash into the biochar. – Ash adds important minerals (calcium, sulfur, potassium, phosphorus, magnesium) ~14~