Soils 102 – Chemical properties

It’s more than just salt...

Outline Introduction Topics: –Nutrients –pH –salinity/sodicity Practical matters Summary

Introduction Chemical elements...

Chemical elements Nitrogen –nitrate –ammonium Phosphorous Potassium Calcium Magnesium Aluminum Sodium Hydrogen N –NO 3 - –NH 4 + P (PO 4 3-) K (K + ) Ca (Ca 2+ ) Mg (Mg 2+ ) Al (Al 3+ ) Na (Na + ) H (H + )

Introduction Chemical elements... Where are the nutrients, salts, etc.?

Mineral particle (sand, silt, clay)

Fe2+ Al3+ Mg2+ Ca2+Al3+ Mg2+ K+ Ca2+ K+

Mineral particle (sand, silt, clay) Mg2+ H+ K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ Mg2+ H+ Ca2+ Na+ Ca2+ H+ K+ Al3+ Fe2+ Al3+ Mg2+ Ca2+Al3+ Mg2+ K+ Ca2+ K+ Adsorbed to particle surface

Mineral particle (sand, silt, clay) Mg2+ H+ K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ Mg2+ H+ Ca2+ Na+ Ca2+ H+ K+ Al3+ Mg2+ H+ Ca2+ Na+ Ca2+ H+ K+ Al3+ Adsorbed to particle surface Available in soil water Fe2+ Al3+ Mg2+ Ca2+Al3+ Mg2+ K+ Ca2+ K+

Nutrients How are nutrients held to the mineral soil?

Mineral particle (sand, silt, clay) Mg2+ H+ K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ Mg2+ H+ Ca2+ Na+ Ca2+ H+ K+ Al3+ Mg2+ H+ Ca2+ Na+ Ca2+ H+ K+ Al3+ Available in soil water Negative charges on particle surface Adsorbed to particle surface

Nutrients How are nutrients held to the mineral soil? Organic matter – another source

Mg2+ H+ NO3- K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ PO4- K+ Ca2+ Al3+ Na+ K+ Ca2+ NO3- H+ Mg2+ H+ Ca2+ Na+ Ca2+ PO4- K+ Al3+ Mg2+ H+ Ca2+ Na+ Ca2+ PO4- K+ Al Organic matter

Mg2+ H+ NO3- K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ PO4- K+ Ca2+ Al3+ Na+ K+ Ca2+ NO3- H+ Mg2+ H+ Ca2+ Na+ Ca2+ PO4- K+ Al3+ Mg2+ H+ Ca2+ Na+ Ca2+ PO4- K+ Al

Ca2+ Mg2+ H+ NO3- K+ Ca2+ Al3+ Na+ K+ Ca2+ Mg2+ H+ PO4- K+ Ca2+ Al3+ Na+ K+ Ca2+ NO3- H+ Mg2+ H+ Ca2+ Na+ Ca2+ PO4- K+ Al3+ Mg2+ H+ Ca2+ Na+ Ca2+ PO4- K+ Al NH4+ K+ H+ Na+ PO 4 - Mg NO K+ NO3- NH 4 +

pH

A measure of acidity/alkalinity

pH A measure of acidity/alkalinity 1714 AcidNeutralBase

pH A measure of acidity/alkalinity Which nutrients are basic, acid? 1714 AcidNeutralBase

pH A measure of acidity/alkalinity Which nutrients are basic, acid? –Basic – Ca 2+, Mg 2+, K +, (Na + ) –Acid – H +, Al 3+, Sulfur 1714 AcidNeutralBase

pH A measure of acidity/alkalinity Which nutrients are basic, acid? Which of these predominate in the Plains? 1714 AcidNeutralBase

Location H+, Al3+ Ca2+Mg2+K+Na+ %%% Hawaii851032tr New England tr Southeast Lake States S. Central Midwest Southwest

pH A measure of acidity/alkalinity Which nutrients are basic, acid? Which of these predominate in the Plains? Average pH of ND soils? 1714 AcidNeutralBase

Soil pH levels, upland positions, non-manured sites, (Franzen, 1999)

pH A measure of acidity/alkalinity Which nutrients are basic, acid? Which of these predominate in the Plains? Average pH of ND soils? How pH affects nutrient availability 1714 AcidNeutralBase

pH A measure of acidity/alkalinity Which nutrients are basic, acid? Which of these predominate in the Plains? Average pH of ND soils? How pH affects nutrient availability How pH affects tree survival and growth 1714 AcidNeutralBase

pH and trees Deciduous more tolerant of high pH than conifers are (Michigan jack pine example)

pH and trees Deciduous more tolerant of high pH than conifers are (Michigan jack pine example) Conifer needle litter reduces the soil pH over time

pH and trees Deciduous more tolerant of high pH than conifers are (Michigan jack pine example) Conifer needle litter reduces the soil pH over time pH < 4  aluminum toxicity

pH and trees Deciduous more tolerant of high pH than conifers are (Michigan jack pine) Conifer needle litter reduces the soil pH over time pH < 4  aluminum toxicity Which conifers appropriate to high pH?

pH and trees Deciduous more tolerant of high pH than conifers are (Michigan jack pine) Conifer needle litter reduces the soil pH over time pH < 4  aluminum toxicity Which conifers appropriate to high pH? –Ponderosa pine –Rocky Mountain juniper –Eastern redcedar

Salinity

High soluble salt concentration

Salinity High soluble salt concentration Not necessarily high sodium salts

Soluble salts NaCl Na 2 SO 4 NaHCO 3 Na 2 CO 3 MgCl 2 MgSO 4 CaCl 2 Sodium chloride Sodium sulfate Sodium bicarbonate Sodium carbonate Magnesium chloride Magnesium sulfate Calcium chloride

How do saline soils (seeps) develop?

Salts already present (esp. W of Mo. Riv.)

How do saline soils (seeps) develop? Salts already present (esp. W of Mo. Riv.) Salts dissolve in water and move

How do saline soils (seeps) develop? Salts already present (esp. W of Mo. Riv.) Salts dissolve in water and move Water evaporates, leaving concentrated salts

Saline soils in Grand Forks County (Seelig, 2000)

Formation of saline seeps (Seelig, 2000)

Salinity High soluble salt concentration Not necessarily high sodium salts Measured by electrical conductivity (EC) –Units are mmhos or dS/m

Salinity High soluble salt concentration Not necessarily high sodium salts Measured by electrical conductivity (EC) –Units are mmhos or dS/m –NDSU soils lab recommendations: 0-1 Non-saline 1-2 Very slightly saline 2-4 Slightly saline 4-6 Saline >6 Strongly saline

>6NDSU: NRCS: (S.E.)

Salt tolerant – Salt sensitive

sea-buckthorn (9) silver buffaloberry (9) silverberry (9) Russian-olive (9) green ash (9) caragana (9) skunkbush sumac (9) junipers (9) (lilac) (9) (honeysuckle) (9) (ponderosa pine) (juneberry) (chokecherry)

Salt tolerant – Salt sensitive sea-buckthorn (9) silver buffaloberry (9) silverberry (9) Russian-olive (9) green ash (9) caragana (9) skunkbush sumac (9) junipers (9) (lilac) (9) (honeysuckle) (9) (ponderosa pine) (juneberry) (chokecherry) Sand cherry Dogwood Little-leaf linden Hybrid poplar * Black walnut Manchurian apricot (crabapple) (American plum)

Salinity High soluble salt concentration Not necessarily high sodium salts Measured by electrical conductivity (EC) Saline vs. sodic vs. saline-sodic

Soil Common pH Electrical Conductivity Sodium adsorption ratio Normal6.5 – 7.2<4<13-15 Saline<8.5>4<13-15 Saline- sodic <8.5>4>13-15 Sodic>8.5<4>13-15 Data from Brady, 1990

ND saline and sodic soils (Seelig, 2000)

Salinity High soluble salt concentration Not necessarily high sodium salts Measured by electrical conductivity (EC) Saline vs. sodic vs. saline-sodic Trees are more sensitive at germination, or while they’re really getting established.

How to manage saline soils?

Control water table depth by: –Direct the drainage (tiles) –Deep-rooted perennials along ditches –Don’t summer fallow; use continuous cropping How to manage saline soils?

Control water table depth by: –Direct the drainage (tiles) –Deep-rooted perennials along ditches –Don’t summer fallow; use continuous cropping Grow a salt-tolerant crop or green mulch on seeps How to manage saline soils?

Control water table depth by: –Direct the drainage (tiles) –Deep-rooted perennials along ditches –Don’t summer fallow; use continuous cropping Grow a salt-tolerant crop or green mulch on seeps Shallow tillage How to manage saline soils?

Control water table depth by: –Direct the drainage (tiles) –Deep-rooted perennials along ditches –Don’t summer fallow; use continuous cropping Grow a salt-tolerant crop or green mulch on seeps Shallow tillage Leave stubble nearby to capture moisture which leaches salts out How to manage saline soils?

Summary Soils provide nutrients to plants

Summary Soils provide nutrients to plants Soil pH affects nutrient availability and tree species selection

Summary Soils provide nutrients to plants Soil pH affects nutrient availability and tree species selection Many soils in ND are saline, with a limited number of adapted tree species

Summary Soils provide nutrients to plants Soil pH affects nutrient availability and tree species selection Many soils in ND are saline, with a limited number of adapted tree species Managing saline soils means managing water movement

Questions?