ARS | Publication request: DISTRIBUTION AND AMOUNT OF SOIL ORGANIC CARBON IN LONG-TERM MANAGEMENT SYSTEMS IN TEXAS

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 16, 1998
Publication Date: N/A

Interpretive Summary: Soil organic carbon is an important soil property which is often used as an indicator of soil quality. Historically, tillage has resulted in a decreas in soil organic carbon which has decreased soil quality, but modern reduced tillage and no-till farming systems have often increased soil organic carbo onear the surface. This has been found most often in the Northern parts of the United States where it is colder and where reduced tillage farming systems have been more rapidly adopted. The effect of reduced tillage farming systems in Texas can only now be evaluated because research has bee conducted long enough to make the effects of reduced tillage on soil organi carbon measurable. In this study, 10 or more years of no-till management altered carbon distribution in soil at 3 widely spaced locations in Texas; Bushland, Temple, and Corpus Christi. No-till increased soil organic carbo oamounts in 16 of 20 management comparisons possible in this study. Climat affected soil organic carbon storage, which decreased at higher annual temperatures when similar crop and management systems were compared. Conditions have been determined which allow increases in organic carbon in soils in Texas.

Technical Abstract: Soil organic carbon (SOC) distribution is altered by residue management practices, but the effect on total carbon mass is not well understood, especially in warm regions. The objective of this study was to determine the effect of residue management practices on SOC distribution and amount across an 1100-km transect (northwest to southeast) of Texas. Long-term (>10 yr) continuous cropping rotation and residue management plots located near Bushland, Temple, and Corpus Christi, Texas, were sampled incrementally with depth for SOC distribution and mass. The mass of SOC varied among locations depending on management, and climatic conditions. No-tillage management resulted in increased SOC concentration and mass in the surface 0.07 m in comparison to more intensive tillage management (e.g.sweep, chisel plow, moldboard plow). Fertilization had little effect oncarbon sequestration at any site. Carbon sequestration decreased as meanannual temperature increased. Carbon may be sequestered in soil underTexas climatic conditions, but the amounts may be quite small.