Is it possible to attain the same soil organic matter content in arable agricultural soils as under natural vegetation?

Abstract

Clearing natural vegetation to establish arable agriculture (cropland) almost invariably causes a loss of soil organic carbon (SOC). Is it possible to restore soil that continues in arable agriculture to the pre-clearance SOC level through modified management practices? To address this question we reviewed evidence from long-term experiments at Rothamsted Research, UK, Bad Lauchstädt, Germany, Sanborn Field, USA and Brazil and both experiments and surveys of farmers’ fields in Ethiopia, Australia, Zimbabwe, UK and Chile. In most cases SOC content in soil under arable cropping was in the range 38–67% of pre-clearance values. Returning crop residues, adding manures or including periods of pasture within arable rotations increased this, often to 60–70% of initial values. Under tropical climatic conditions SOC loss after clearance was particularly rapid, e.g. a loss of >50% in less than 10 years in smallholder farmers’ fields in Zimbabwe. If larger yielding crops were grown, using fertilizers, and maize stover returned instead of being grazed by cattle, the loss was reduced. An important exception to the general trend of SOC loss after clearance was clearing Cerrado vegetation on highly weathered acidic soils in Brazil and conversion to cropping with maize and soybean. Other exceptions were unrealistically large annual applications of manure and including long periods of pasture in a highly SOC-retentive volcanic soil. Also, introducing irrigated agriculture in a low rainfall region can increase SOC beyond the natural value due to increased plant biomass production. For reasons of sustainability and soil health it is important to maintain SOC as high as practically possible in arable soils, but we conclude that in the vast majority of situations it is unrealistic to expect to maintain pre-clearance values. To maintain global SOC stocks at we consider it is more important to reduce current rates of land clearance and sustainably produce necessary food on existing agricultural land.

Temperate fruit farming in fragile lands of the Northwestern Himalayan region: Implications for subsoil nutrient availability, nutrient stock and soil quality

“…A recent study in Almora, Uttarakhand (Meena et al, 2018) also revealed a higher accumulation of SOC, down to a depth of 45 cm, in FLs as compared to cultivated lands. The observed build up of SOC content in the natural grasslands (FL; Figure 2d) could also be due to its continuous incorporation through root litter (Powlson et al, 2022). Additionally, these soils are rarely disturbed by cultural practices that are otherwise followed in orchard soils (e.g., monsoon or winter plowing) of the present study.…”

“…Land use and its management not only changes the nutrients' availability (Dad & Abdollahi, 2021; Loria et al, 2016; Silva‐Olaya et al, 2022), their stocks (Chatterjee et al, 2020; Powlson et al, 2022), and stoichiometry (Buchkowski et al, 2019) in soils but also it is equally important to evaluate their impacts on the ability of the soil to function, that is, soil quality (Basak et al, 2021; Bhaduri & Purakayastha, 2014). Some of the soil parameters in these fragile land use systems might reflect an early sign of soil quality deterioration.…”

How much organic carbon could the soil store? The carbon sequestration potential of Australian soil

“…Janzen et al. (2022) point out that the limit is imposed by photosynthesis; this is true in natural systems and in arable agriculture (Powlson et al., 2022).…”

Degradation Status and Local Community Perception towards Kadar-Basaso Wetland in Sinana District of Bale Zone, South Eastern Ethiopia

“…Sand particles have a low charge and do not reach. As a result, high-clay soils can contain more cations than low-clay soils [60].…”