Intra-annual variation in soil C, N and nutrients pools after prescribed fire in a Mississippi longleaf pine (Pinus palustris Mill.) plantation

Abstract

Prescribed fire is an essential tool that is widely used for longleaf pine (Pinus palustris Mill.) stand management; periodic burning serves to reduce competition from woody shrubs and fire-intolerant trees and enhance herbaceous diversity. Low-intensity, prescribed burning is thought to have minimal long-term impact on soil chemistry in southern pine forests, although few studies report the intra-annual variation in soil chemistry after burning. We monitored changes in C, N, oxidation resistant C (CR), pH and elemental nutrients in the forest floor and soil (0-5, 5-10 cm depths) before and after burning (1, 3, 6, 12 months) in a mature longleaf pine plantation at the Harrison Experimental Forest, near Saucier, Mississippi. Prescribed fire consumed much of the forest floor (11.3 Mg ha-1; -69%), increased soil pH and caused a pulse of C, N and elemental nutrients to flow to the near surface soils. In the initial one to three months post-burn coinciding with the start of the growing season, retention of nutrients by soil peaked. Most of the N (93%), Ca (88%), K (96%) and Mg (101%), roughly half of the P (48%) and Mn (52%) and 25% of the C lost from the forest floor were detected in the soil and apparently not lost to volatilization. By month 12, soil C and N pools were not different at depths of 0-5 cm but declined significantly below pre-burn levels at depths of 5-10 cm, C -36% (p = 0.003), contrary to other examples in southern pine ecosystems. In the upper 5 cm of soil, only Cu (-49%) remained significantly lower than pre-burn contents by month 12, at depths of 5–10 cm, Cu (-76%), Fe (-22%), K (-51%), Mg (-57%), Mn (-82%) and P (-52%) remain lower at month 12 than pre-burn contents. Burning did not increase soil CR content, conversely significant declines in CR occurred. It appears that recovery of soil C and N pools post-burn will require more time on this site than other southern pine forests.

  • Citation: Butnor, John R.; Johnsen, Kurt H.; Maier, Christopher A.; Nelson, C. Dana. 2020. Intra-annual variation in soil C, N and nutrients pools after prescribed fire in a Mississippi longleaf pine (Pinus palustris Mill.) plantation. Forests. 11(2): 181-. https://doi.org/10.3390/f11020181.
  • Keywords: forest soils, prescribed fire, carbon, nitrogen, phosphorus, potassium, calcium, priming, Harrison Experimental Forest, longleaf pine
  • Posted Date: February 11, 2020
  • Modified Date: February 12, 2020
  • Print Publications Are No Longer Available

    In an ongoing effort to be fiscally responsible, the Southern Research Station (SRS) will no longer produce and distribute hard copies of our publications. Many SRS publications are available at cost via the Government Printing Office (GPO). Electronic versions of publications may be downloaded, printed, and distributed.

    Publication Notes

    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
    • Our online publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS webmaster if you notice any errors which make this publication unusable.
    • To view this article, download the latest version of Adobe Acrobat Reader.