Sulfate Sorption in Andic Soils of the Inland Northwest Presented by Mark Kimsey M.S. Candidate in Soil Science May 2003

Defense Outline Why this topic?Why this topic? Study designStudy design Sample collection/Laboratory analysesSample collection/Laboratory analyses FindingsFindings Conclusions/ImplicationsConclusions/Implications

Why this topic?

Deficiency, Deficiency, DeficiencyDeficiency, Deficiency, Deficiency Often upon application of sulfurOften upon application of sulfur fertilizer, deficiencies are not fertilizer, deficiencies are not always alleviated always alleviated Sulfur has been diagnosed asSulfur has been diagnosed as deficient in many forest stands deficient in many forest stands across the Inland Northwest across the Inland Northwest

DF CNC

Why?

Other critical nutrients more Other critical nutrients more limiting than sulfur limiting than sulfur Current sulfur application Current sulfur application amounts not sufficient to supply amounts not sufficient to supply conifer nutrient demands conifer nutrient demands Sulfur-soil interactions limiting Sulfur-soil interactions limiting sulfur bioavailability sulfur bioavailability

Common Soil Feature

VOLCANIC ASH

Sulfur & Volcanic Ash

Sulfur, applied as SO 4 2-, Sulfur, applied as SO 4 2-, possesses a negative charge, and possesses a negative charge, and is thus able to be retained by is thus able to be retained by soils with an Anion Exchange soils with an Anion Exchange Capacity (AEC) Capacity (AEC) Volcanic ash, as it weathers, Volcanic ash, as it weathers, forms variably-charged, poorly forms variably-charged, poorly crystalline aluminosilicates and crystalline aluminosilicates and Fe oxides Fe oxides

In turn, the positive charge In turn, the positive charge will attract the negatively will attract the negatively charged SO 4 2- ion charged SO 4 2- ion Within this pH range, variable Within this pH range, variable charged minerals will possess a charged minerals will possess a positive charge positive charge Typical Inland Northwest forest Typical Inland Northwest forest soil pHs range between soil pHs range between

(Gebhardt & Coleman. 1979; Hue et al. 1990) Adsorbed sulfate was found to be Adsorbed sulfate was found to be strongly bound against hydrolysis strongly bound against hydrolysis Sulfate has 10 times greater Sulfate has 10 times greater affinity for adsorption sites affinity for adsorption sites than does NO 3 - and Cl - than does NO 3 - and Cl - Andic soils of the Caribbean, Andic soils of the Caribbean, Pacific Rim Islands, and Hawaii Pacific Rim Islands, and Hawaii possess large sulfate adsorption possess large sulfate adsorption capacities capacities 300 – 11,000 kg/ha300 – 11,000 kg/ha

The Question

Does the presence of volcanic ash in Inland Northwest forest soils affect SO 4 2- adsorption/ desorption patterns?Does the presence of volcanic ash in Inland Northwest forest soils affect SO 4 2- adsorption/ desorption patterns?

Objectives

Determine SO 4 2- desorption Determine SO 4 2- desorption behavior behavior Determine SO 4 2- adsorption capacity Determine SO 4 2- adsorption capacity Assess the range of volcanic ash Assess the range of volcanic ash influence in INW forest soils influence in INW forest soils

Study Design

Sample Collection

Laboratory Analyses

Assessing VA influenceAssessing VA influence - NaF pH (1:50 (soil:1N NaF)) - Selective Soil Extraction Ammonium oxalate Ammonium oxalate - SSE samples were hi-speed centrifuged, filtered (0.21μm), and centrifuged, filtered (0.21μm), and analyzed by ICP-AES for Fe, Al, Si analyzed by ICP-AES for Fe, Al, Si

SO 4 2- adsorptionSO 4 2- adsorption - Adsorption Isotherms 1:5 (soil:X ppm Na 2 SO 4 )1:5 (soil:X ppm Na 2 SO 4 ) 50,100,200,400,800 ppm Na 2 SO 450,100,200,400,800 ppm Na 2 SO 4 - Kinetics 1:5 (soil:200 ppm Na 2 SO 4 )1:5 (soil:200 ppm Na 2 SO 4 ) Time steps:Time steps: 1/2,1,2,4,8,12,24,48 h 1/2,1,2,4,8,12,24,48 h - All soil solutions were hi-speed centrifuged, filtered (0.21μm), and centrifuged, filtered (0.21μm), and analyzed by IC for C e SO 4 2- analyzed by IC for C e SO 4 2-

SO 4 2- adsorptionSO 4 2- adsorption Equilibrium and adsorbed data Equilibrium and adsorbed data were plotted using the linear were plotted using the linear form of the two equations form of the two equations - Modeling Two modeling equations were Two modeling equations were selected: selected: –Langmuir Equilibrium Approach –Freundlich Equilibrium Approach The equation that yielded the The equation that yielded the best fit, was selected to model best fit, was selected to model SO 4 2- adsorption SO 4 2- adsorption

SO 4 2- desorptionSO 4 2- desorption -Step 2 Slurry hi-speed centrifuged, Slurry hi-speed centrifuged, filtered (0.21μm) and analyzed filtered (0.21μm) and analyzed for equilibrium SO 4 2- conc. for equilibrium SO 4 2- conc. - Step 1 Three soils with a wide range in Three soils with a wide range in volcanic ash influence were volcanic ash influence were shaken for 8 h in a 1:5 shaken for 8 h in a 1:5 (soil:200 ppm Na 2 SO 4 ) slurry (soil:200 ppm Na 2 SO 4 ) slurry

SO 4 2- desorptionSO 4 2- desorption – Step 4 Soil samples were shaken for 48 h, Soil samples were shaken for 48 h, hi-speed centrifuged, filtered hi-speed centrifuged, filtered (0.21μm), and analyzed by IC for (0.21μm), and analyzed by IC for desorbed SO 4 2- desorbed SO Step 3 NaSO 4 2- solution was replaced NaSO 4 2- solution was replaced with a 0.01 M CaCl 2 solution with a 0.01 M CaCl 2 solution

Findings

Assessment of Volcanic Ash Influence

ox

r = 0.91*** ox

SO 4 2- Adsorption Kinetics

UF – 200 ppm NaSO 4

SO 4 2- Adsorption Isotherms

Costa Rica Tollgate Swamp 2 Noregaard Santa Notch 3

SO 4 2- Adsorption Modeling Freundlich Equation

Costa Rica Tollgate Swamp 2 Noregaard Santa Notch 3 Observed Predicted

SO 4 2- Desorption

Tying it Together

r = 0.96*** r = 0.08 ns

r = 0.71*** r = 0.10 ns

Conclusions

Soils highly influenced by Soils highly influenced by volcanic ash have high SO 4 2- volcanic ash have high SO 4 2- adsorption capacities (>35%) adsorption capacities (>35%) All INW forest soils are able All INW forest soils are able to adsorb 10-15% of added SO 4 2- to adsorb 10-15% of added SO 4 2- Inland Northwest forest soils Inland Northwest forest soils have a wide range in volcanic have a wide range in volcanic ash influence ash influence

The Freundlich equation can be The Freundlich equation can be used to predict SO 4 2- adsorption used to predict SO 4 2- adsorption capacity capacity NaF pH values > 10.5 and % Al ox NaF pH values > 10.5 and % Al ox + ½ % Fe ox values > 1.5 indicate + ½ % Fe ox values > 1.5 indicate increasing ability to adsorb SO 4 2- increasing ability to adsorb SO 4 2- NaF pH and % Al ox + ½ % Fe ox are NaF pH and % Al ox + ½ % Fe ox are highly correlated and predict highly correlated and predict SO 4 2- adsorption well SO 4 2- adsorption well

Only ~ 2% of adsorbed SO 4 2- wasOnly ~ 2% of adsorbed SO 4 2- was desorbed in soils strongly desorbed in soils strongly influenced by volcanic ash influenced by volcanic ash

Implications

Forest soil pore water dynamics Forest soil pore water dynamics on sulfate adsorption/desorption on sulfate adsorption/desorption patterns patterns Sulfur fertilizer efficiency Sulfur fertilizer efficiency

Acknowledgements Acknowledgements Committee Family Dr. Paul McDaniel Mark Kimsey, Sr. Dr. Daniel Strawn Kari Kimsey Dr. Bob Mahler Christopher Kimsey Dr. Jim Moore Dr. John Mandzak IFTNC UI Stillinger Trust Terry Shaw Mariann JohnstonAnita Falen Peter Mika

THANK YOU ANY QUESTIONS?