Results Growth response to P fertilization on a 20 yr old loblolly pine plantation in coastal SC.
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Results Growth response to P fertilization on a 20 yr old loblolly pine plantation in coastal SC. 0 20 40 60 80 100 P m g/kg M ehlich 1 M ehlich 3 Labile P M oderately Labile P N aO H Pi Discussion Conclusion • The increase in Hedley labile P suggest there is a long-term impact of a single P fertilization in loblolly pine forests, and therefore some sites may not require P fertilization at establishment of subsequent rotations. •Understanding how soil microbes affect organic P, moderately labile P, and recalcitrant P pools may lead to more accurate soil based predictions of labile P pools. Acknowledgement Funding provided by USDA NRI Competitive Grant Program. Funding provided by USDA NRI Competitive Grant Program. Dissertation Committee: J. Burger and L. Zelanzy, Dissertation Committee: J. Burger and L. Zelanzy, Virginia Tech. Virginia Tech. L. Allen, NCSU. F. Sanchez , USFS-SRS. L. Allen, NCSU. F. Sanchez , USFS-SRS. “Leaves grow trees, Resources grow leaves” Forest Nutrition Co-Op References NCSFNC. 2004. Responses to nutrient additions in young loblolly pine plantations: Regionwide 18 fifth report. Department of Forestry, NCSU and Virginia Tech., Raleigh, NC. Tiessen, H., and J.O. Moir. 1993. Characterization of available P by sequential extraction. Lewis Publishers. Turner, J., and M.J. Lambert. 1988. Long-term effects of phosphorus fertilization on forests., p. 125-133, In B. B. and W. C. H., eds. Forest site evaluation and long-term productivity. University of Washington Press, Seattle, WA. Vadas, P.A., P.J.A. Kleinman, A.N. Sharpley, and B.L. Turner. 2005. Relating Soil Phosphorus to Dissolved Phosphorus in Runoff: A Single Extraction Coefficient for Water Quality Modeling. J Environ Qual 34:572- 580. ong-term changes in Hedley phosphorus pools in response to a single P fertilization in a southeastern US loblolly pine plantation. Bradley W. Miller Department of Forestry Corresponding Author: [email protected] Thomas R. Fox Department of Forestry Environmental & Social Considerations • Phosphorus (P) fertilization can dramatically increase tree growth in nutrient deficient soils of the southeastern US (NCSFNC, 2004). Increased productivity could reduce the hectares required to meet our societies wood product needs. • Phosphorus applied to soils is rapidly sequestered by plants, microbes, or chemically sorbed to soil mineral becoming less plant available (labile) over time (Turner and Lambert, 1988) . • Phosphorus runoff into streams and rivers is a major contributor to the eutrophication of our waterways (Vadas et al., 2005) . • Understanding how much Hedley P remains labile over time may lead to a reduction of P fertilizer prescribed during planting, and therefore reduce the chance of P pollution of our waterways. Phosphorus fertilization at stand establishment. Research Objectives • Determine the long-term effects of P fertilization on soil biogeochemical phosphorus pools using the Hedley sequential fractionation procedure. • Determine the long-term effects of P fertilization on labile P pools in forest soils. Hypothesis • Ha: Fertilized sites would have greater labile P content than the control sites. Methods Hedley Fractionation Procedure 0 lbs/ac P at Planting 50 lbs/ac P at Planting • Routine soil analyses were Routine soil analyses were performed: Mehlich-1 and performed: Mehlich-1 and Mehlich-3 soil P test. Mehlich-3 soil P test. • Modified Hedley Modified Hedley fractionation uses 0.5 g soil fractionation uses 0.5 g soil subjected to a series of subjected to a series of extracting solutions of extracting solutions of increasing strength increasing strength (Tiessen and Moir (Tiessen and Moir 1993) 1993) . • Fractions represent the Fractions represent the strength of P held by soil strength of P held by soil colloids and can be grouped colloids and can be grouped based on the bio-availability based on the bio-availability of the P pool: of the P pool: • Labile – Plant available during one growing season. • Moderately Labile – Plant available over time • Recalcitrant – Not plant available • Loblolly pine tree growth increased by greater than 2 meters on many sites in the southeastern US. • P fertilization resulted in a sustained growth increase compared to control sites. Mehlich-1, Mehlich-3, and Hedley P fractions from a loblolly pine plantation 20 yrs after fertilization in SC. Hedley P fractions from a loblolly pine plantation soil 20 years after fertilization in SC. •Labile P pools (green) remain significantly higher (p=0.04) in the 0-10 cm soil horizon of the fertilized plots 20 years after application. •Labile P decreased with depth. •A majority of P is found in the Hedley NaOH recalcitrant fraction which represents P bound to Fe and Al oxides. •Mehlich-3 results show a significant (p=0.02) increase in extractable P in the 0-10 cm soil horizon of the fertilized sites. •Results suggest that Mehlich-3 extracts from recalcitrant P pools including P bound to Fe and Al oxides. •Mehlich-1 P was less than Hedley labile P pools in the 0-10 cm soil horizon. • H a : Twenty years after fertilization Hedley labile P and Mehlich-3 P are significantly higher in the 0-10 cm soil horizon of the fertilized plots. • Hedley P o pools increased by 72% in 0-10 cm soil horizon of the fertilized sites. These P o pools may be acting as a long-term source of labile P for loblolly pine growth. • Mehlich-3 extracts P using an organic chelator to solubilize P from recalcitrant P pools. Soil microbes produce analogous compounds in situ, therefore these P pools may be labile. Photo: D. Blevins 0 10 20 30 40 50 60 70 80 C n*0-10 Fert *0-10 C n*10-20 Fert *10-20 P m g/kg Resin Bicarb Po Bicarb Pi N aO H Po N aO H Pi HC l Pi C oncH C l Po C oncH C l Pi HSO4 P Cn * 0 - 10 Cn * 10- 20 Fert * 10-20 Fert * 0- 10 Treatment * Depth (cm) Treatment * Depth (cm)
description
Cn * 0 -10. Cn * 10-20. Fert * 10-20. Fert * 0-10. Bradley W. Miller Department of Forestry Corresponding Author: [email protected]. - PowerPoint PPT Presentation
Transcript of Results Growth response to P fertilization on a 20 yr old loblolly pine plantation in coastal SC.
Results
Growth response to P fertilization on a 20 yr old loblolly pine plantation in coastal SC.
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Discussion
Conclusion
• The increase in Hedley labile P suggest there is a long-term
impact of a single P fertilization in loblolly pine forests, and
therefore some sites may not require P fertilization at
establishment of subsequent rotations.
•Understanding how soil microbes affect organic P,
moderately labile P, and recalcitrant P pools may lead to
more accurate soil based predictions of labile P pools.
AcknowledgementFunding provided by USDA NRI Competitive Grant Program.Funding provided by USDA NRI Competitive Grant Program.
Dissertation Committee: J. Burger and L. Zelanzy, Virginia Tech. Dissertation Committee: J. Burger and L. Zelanzy, Virginia Tech. L. Allen, L. Allen, NCSU. F. Sanchez , USFS-SRS.NCSU. F. Sanchez , USFS-SRS.
“Leaves grow trees, Resources grow leaves” Forest Nutrition Co-Op
ReferencesNCSFNC. 2004. Responses to nutrient additions in young loblolly pine plantations: Regionwide 18 fifth report. Department of Forestry, NCSU and Virginia Tech., Raleigh, NC.
Tiessen, H., and J.O. Moir. 1993. Characterization of available P by sequential extraction. Lewis Publishers.
Turner, J., and M.J. Lambert. 1988. Long-term effects of phosphorus fertilization on forests., p. 125-133, In B. B. and W. C. H., eds. Forest site evaluation and long-term productivity. University of Washington Press, Seattle, WA.
Vadas, P.A., P.J.A. Kleinman, A.N. Sharpley, and B.L. Turner. 2005. Relating Soil Phosphorus to Dissolved Phosphorus in Runoff: A Single Extraction Coefficient for Water Quality Modeling. J Environ Qual 34:572-580.
Long-term changes in Hedley phosphorus pools in response to a single P fertilization in a southeastern US loblolly pine plantation. Bradley W. Miller Department of Forestry
Corresponding Author: [email protected]
Thomas R. Fox Department of Forestry
Environmental & Social Considerations
• Phosphorus (P) fertilization can dramatically increase tree growth in nutrient
deficient soils of the southeastern US (NCSFNC, 2004). Increased productivity could
reduce the hectares required to meet our societies wood product needs.
• Phosphorus applied to soils is rapidly sequestered by plants, microbes, or
chemically sorbed to soil mineral becoming less plant available (labile) over time
(Turner and Lambert, 1988) .
• Phosphorus runoff into streams and rivers is a major contributor to the
eutrophication of our waterways (Vadas et al., 2005) .
• Understanding how much Hedley P remains labile over time may lead to a
reduction of P fertilizer prescribed during planting, and therefore reduce the
chance of P pollution of our waterways.
Phosphorus fertilization at stand establishment.
Research Objectives
• Determine the long-term effects of P fertilization on soil
biogeochemical phosphorus pools using the Hedley sequential
fractionation procedure.
• Determine the long-term effects of P fertilization on labile P pools in
forest soils.
Hypothesis• Ha: Fertilized sites would have greater labile P content than the control sites.
MethodsHedley Fractionation Procedure
0 lbs/ac P at Planting 50 lbs/ac P at Planting
• Routine soil analyses were performed: Routine soil analyses were performed:
Mehlich-1 and Mehlich-3 soil P test.Mehlich-1 and Mehlich-3 soil P test.
•Modified Hedley fractionation uses 0.5 g Modified Hedley fractionation uses 0.5 g
soil subjected to a series of extracting soil subjected to a series of extracting
solutions of increasing strengthsolutions of increasing strength (Tiessen and Moir 1993)(Tiessen and Moir 1993) ..
•Fractions represent the strength of P held Fractions represent the strength of P held
by soil colloids and can be grouped based by soil colloids and can be grouped based
on the bio-availability of the P pool:on the bio-availability of the P pool:
• Labile – Plant available during one
growing season.
• Moderately Labile – Plant available
over time
• Recalcitrant – Not plant available
• Loblolly pine tree growth increased by greater than 2 meters on many sites in the southeastern US. • P fertilization resulted in a sustained growth increase compared to control sites.
Mehlich-1, Mehlich-3, and Hedley P fractions from a loblolly pine plantation 20 yrs after fertilization in SC.
Hedley P fractions from a loblolly pine plantation soil 20 years after fertilization in SC.
•Labile P pools (green) remain significantly higher (p=0.04) in the 0-10 cm soil horizon of the fertilized plots 20 years after application.
•Labile P decreased with depth.
•A majority of P is found in the Hedley NaOH recalcitrant fraction which represents P bound to Fe and Al oxides.
•Mehlich-3 results show a significant (p=0.02) increase in extractable P in the 0-10 cm soil horizon of the fertilized sites.
•Results suggest that Mehlich-3 extracts from recalcitrant P pools including P bound to Fe and Al oxides.
•Mehlich-1 P was less than Hedley labile P pools in the 0-10 cm soil horizon.
• Ha: Twenty years after fertilization Hedley labile P and
Mehlich-3 P are significantly higher in the 0-10 cm soil
horizon of the fertilized plots.
• Hedley Po pools increased by 72% in 0-10 cm soil horizon
of the fertilized sites. These Po pools may be acting as a long-
term source of labile P for loblolly pine growth.
• Mehlich-3 extracts P using an organic chelator to solubilize
P from recalcitrant P pools. Soil microbes produce analogous
compounds in situ, therefore these P pools may be labile.
Photo: D. Blevins
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ResinBicarb PoBicarb PiNaOH PoNaOH PiHCl PiConcHCl PoConcHCl PiHSO4 P
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