Soil-profile fertility is altered by land use under different physiographic regions in the southeastern USA

Authors: Franzluebbers, Alan; Kafle, Arjun; Zentella Gomez, Rodolfo; FARMAHA, BHUPINDER - Clemson University

Submitted to: Nutrient Cycling in Agroecosystems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2025
Publication Date: 3/22/2025
Citation: Franzluebbers, A.J., Kafle, A., Zentella Gomez, R., Farmaha, B.S. 2025. Soil-profile fertility is altered by land use under different physiographic regions in the southeastern USA. Nutrient Cycling in Agroecosystems. Vol. 117. https://doi.org/10.1002/agj2.70041.
DOI: https://doi.org/10.1002/agj2.70041

Interpretive Summary: Soil fertility is likely to be affected by land use, and yet, databases to characterize these changes by conservation land uses are not readily available. Scientists with ARS in Raleigh North Carolina undertook a comprehensive evaluation of soil fertility conditions across research stations and private farms in North Carolina and Virigina to help interpret how conservation land use can be expected to enrich or degrade soil fertility. Soil fertility was characterized by traditional soil chemical analyses, but also from contemporary soil biological and physical properties often used for soil health analysis. Soils under no-till cropping had greater nutrient supplying capacity and capacity to resist erosion than soils under conventional-till cropping. Soil under perennial pastures had greater soil-profile potassium supply and enriched biological activity compared with no-till cropland. Soil under woodland was enriched in organic matter, but yet had lower base cations and pH than agricultural soils. These results will be useful for land-use planners, extension specialists, farmers, and scientists engaged in soil restoration strategies.

Technical Abstract: Soil fertility is often considered a function of soil chemical properties, but holistically encompasses aspects of soil physical and biological properties and processes as well. How conservation land use compared with conventional-till cropland alters soil-profile fertility characteristics has not been comprehensively assessed despite a long history of diverse land uses in the southeastern US. Soil fertility characteristics from routine soil testing and other soil health testing were determined at 0-10-, 10-30-, and 30-60-cm depths in coastal, piedmont, and mountain regions across a combination of 56 research stations and private farms. A total of 614 soil profiles were a part of this preliminary regional assessment. Soil under no-till compared with conventional-till cropland had 59 +/- 65% greater cation exchange capacity, Mehlich-3-extractable Ca and Mg, soil stability index, and soil-test biological activity at 0-10-cm depth, but fewer differences deeper in the profile. Soil under grassland compared with no-till cropland had 29 +/- 24% greater Mehlich-3 K throughout the soil profile, 42 +/- 28% greater soil stability index and soil-test biological activity at 0-10-cm depth, and 16 + 28% lower Mehlich-3 P and Cu and bulk density at 0-10-cm depth. Soil under woodland compared with grassland had 37 +/- 17% lower cation exchange capacity, pH, Mehlich-3 P, Ca, and Mg throughout the soil profile. Cumulative frequency curves for chemical, physical, and biological properties offered a first step towards regional assessments that could be associated with nutrient sufficiency levels.