Long‐term fertilization effects on ¹³C natural abundance, soil aggregation, and deep soil organic carbon sequestration in an Alfisol

Abstract

Although the 13C (13Carbon) natural abundance method is used to study soil C dynamics, scanty information is available on long‐term fertilization effects on soil C sequestration rates along with δ13C in surface (0–30 cm) and deep (30–90 cm) soil layers and their relationships with crop productivities in subtropics. Hence, soil aggregation, δ13C in bulk soils and aggregates, C pools, and sequestration rates were studied in an Indian Alfisol under a 43‐year old wheat (Triticum aestivum L.)‐based cropping system. Treatments were as follows: no mineral fertilizer and no manure (unfertilized control), 100% recommended dose of nitrogen (N), 100% N and 100% recommended phosphorus (NP), 100% N, 100% P, and 100% recommended potassium (NPK), NPK + lime (NPKL), 150% recommended NPK (1.5NPK), and NPK + farmyard manure at 10 Mg ha−1 (NPKF). Plots with NPKF contained 50% higher soil organic C than NPKL in surface soil (0–15‐cm layer). In the 0–90‐cm profile, soil organic C accumulation and sequestration rates in NPKF were ~0.15 and 0.11 Mg ha−1 yr−1 higher than NPKL plots, respectively. The NPKF plots had higher glomalin‐related soil protein and greater recalcitrant C than NPKL, 1.5NPK, and NPK in surface soil. The NPKF plots had higher δ13C values within bulk soils and their aggregates than NPKL and NPK. There were significant correlations between deep soil C sequestration rates with mean crop productivities and δ13C with deep soil C sequestration rates. Overall, NPKF application had the largest surface and deep soil C sequestration with highest crop productivity and hence is recommended.

Long‐term manure application for crop yield stability and carbon sequestration in subtropical region

“…NPKM application accelerates the process of aggregate formation by supplying binding agents at each stages (Tisdall & Oades, 1982). Despite having lower proportion of macroaggregates in NPKM over fallow land, the former had higher aggregateassociated C than the later due to regular C supply and higher biomass return to soils (Ghosh, Bhattacharyya, Agarwal, et al, 2018). Significantly higher aggregate-associated C in the NPKM over NPK plots might be due to the same reason (Bhattacharyya et al, 2012).…”

“…no‐tillage, application of organic fertilizer and straw return) increased SOC stock and improved crop yield (Bhattacharyya et al., 2015). These strategies improve SOC status by enhancing SOC input and maintaining soil structures (Ghosh, Bhattacharyya, Agarwal, et al., 2018). In general, soil extracellular enzymes decompose substrates of varying composition and complexity (Sinsabaugh & Follstad Shah, 2012) and govern SOC sequestration.…”

Temperature sensitivity of soil organic matter mineralization decreases with long‐term N fertilization: Evidence from four Q10 estimation approaches

“…Second, the ability of microorganisms to decompose stable SOM for nutrients increases with temperature, which further suppressed the effects of N availability induced by fertilization. Moreover, long‐term N fertilization in the field stimulates the labile C input from plants and also suppresses the decomposition of recalcitrant SOM at the same time (Lavoie, Mack, & Schuur, ; Zang et al, , ), which increased the C and N availability (Ghosh et al, ; Shahbaz et al, ), and thus decreased temperature sensitivity.…”

Degraded land restoration ecological way through horti‐pasture systems and soil moisture conservation to sustain productive economic viability

“…Pasture acts as a cover crop after October onwards and reduces evaporation loss as well as restricts run off loss (Blanco‐Canqui et al, ). Manures and fertilisers applied to pasture were also utilised by Emblica and Psidium tree because there was no physical barrier between root system of tree and pasture and thus, better availability of nutrients compensated for the lost area and enhanced fruit yield in all treatments (Ghosh, Bhattacharyya, et al, ). Maximum production was recorded in T1 as ~ one‐third run‐off generated was trapped in trenches resulted in significantly higher moisture content over other treatments during the production period.…”