No‐Tillage and Soil‐Profile Carbon Sequestration: An On‐Farm Assessment

Abstract

No‐tillage (NT) farming is superior to intensive tillage for conserving soil and water, yet its potential for sequestering soil organic carbon (SOC) in all environments as well as its impacts on soil profile SOC distribution are not well understood. Thus, we assessed the impacts of long‐term NT‐based cropping systems on SOC sequestration for the whole soil profile (0–60‐cm soil depth) across 11 Major Land Resource Areas (MLRAs: 121, 122, and 125 in Kentucky; 99, 124, 139A in Ohio; and 139B, 139C, 140, 147, and 148 in Pennsylvania) in the eastern United States. Soil was sampled in paired NT and plow tillage (PT) based cropping systems and an adjacent woodlot (WL). No‐tillage farming impacts on SOC and N were soil specific. The SOC and N concentrations in NT soils were greater than those in PT soils in 5 out of 11 MLRAs (121, 122, 124, 139A, and 148), but only within the 0‐ to 10‐cm depth. Below 10 cm, NT soils had lower SOC than PT soils in MLRA 124. The total SOC with NT for the whole soil profile (0–60 cm) did not differ from that with PT (P > 0.10) in accord with several previous studies. In fact, total soil profile SOC in PT soils was 50% higher in MLRA 125, 21% in MLRA 99, and 41% in MLRA 124 compared with that in NT soils. Overall, this study shows that NT farming increases SOC concentrations in the upper layers of some soils, but it does not store SOC more than PT soils for the whole soil profile.

Soil Carbon Sequestration by Switchgrass and No-Till Maize Grown for Bioenergy

“…Information on the effect of maize stover removal under no-till management on soil C from long-term studies has not been available to date [21]. Most of the research on SOC in agricultural production systems focused on C in the 0 to 30 cm depth [22][23][24][25][26][27]. A few studies in which soil sampling has been conducted at greater depths indicate that production agriculture affects soil C deeper in the soil profile [28,29].…”

Modeling soil organic carbon in corn ( Zea mays L.)-based systems in Ohio under climate change

“…As noted earlier, there have been a growing number of authors in recent years who have pointed out limitations to assigning NT as a universal panacea to mitigate climate change through the removal of atmospheric CO 2 into long-term storage in the soil (Gregorich et al 2007;Blanco-Canqui and Lal 2008;Hammons 2009;Powlson et al 2014;VandenBygaart 2016). Four reasons include (1) the stratification of SOC in the profile of NT soils and its concentration at the surface to 20 cm (8 in) relative to PT soils (Powlson et al 2014), with the implication that SOC is merely redistributed, rather than accumulated, over time; (2) climatic limitations, such as the cool, moist region of eastern Canada (Gregorich et al 2007); (3) the definition of "no-till" itself, which can include occasional tillage (VandenBygaart 2016); and (4) a high spatial variability at the farm scale (Blanco-Canqui and Lal 2008).…”

“…There is a large body of evidence in the literature that NT management results in an increase in surface (0 to 20 cm [0 to 8 in]) SOC under many soil types and climatic conditions, though the effectiveness of NT management over PT to sequester C has been hotly debated (Gregorich et al 2007;Blanco-Canqui and Lal 2008;Hammons 2009;Powlson et al 2014;VandenBygaart 2016). The concerns have been addressed in part by two meta-analyses comparing PT to NT, where NT was found to sequester significantly more C than PT to 30 cm (12 in) (Angers and Eriksen-Hamel 2008) and to 160 cm (63 in) (Mangalassery et al 2015).…”

Evaluating the impact of soil conservation measures on soil organic carbon at the farm scale

“…Studies supporting the positive effects of NT on soil C (Lal, 2004) have been countered by studies that report no net C sequestration when compared to CT (Blanco-Canqui and Lal, 2008). There have also been studies that show both CT and NT systems may lead to soil C losses (Kumar et al, 2012) even though these studies were conducted under diverse field conditions (e.g.…”