Plant residue biochemistry regulates soil carbon cycling and carbon sequestration

Abstract

Substrate composition is one of the most important factors in¯uencing the decomposition of plant residues in soils. The interaction of organic residue biochemistry with residue decomposition rates, soil aggregation and soil humus composition was determined in a laboratory experiment. Addition of seven dierent organic residues (2% w/w alfalfa, oat, canola, clover, soybean, corn and prairie grasses) to a Webster soil resulted in a rapid, transient increase in aggregate mean weight diameters (MWD) when incubated for 9 d with residues with low phenolic acid content (alfalfa, canola and clover) and was inversely correlated with soil carbohydrate content r À0X63). More pronounced improvement in aggregate size was noted upon increased incubation to 84 d with organic residues higher in phenolic acid content (corn, prairie grasses, oat and soybean) and was related to soil phenolic acid r 0X65 and soil carbohydrate content r 0X70). Total plant residue phenolic acid content was related to MWD measured after incubation for 84 d by a quadratic response and plateau function r 0X96 and the MWD quadratically increased with an increase in vanillin-vanillic acid concentrations in the plant residues r 0X997). Soil organic C after 84 d was related to the MWD r 0X82 and the residue's vanillin-vanillic acid content r 0X86), suggesting that C remaining in the soil following decomposition maybe related to the speci®c phenolic acid content. The results suggest that transient aggregate stability initiated by microbial decomposition of the carbohydrate and amino acid content of the residue, is then strengthened by the interaction with phenolic acids such as vanillin or vanillic acid released by microbial decomposition from residues structural components. Published by Elsevier Science Ltd.

Carbon, nitrogen and organic C fractions in topsoil affected by conversion from silvopastoral to different land use systems

“…In the long-term, areas under grassland have similar potential to store TOC as areas under tree-based land use systems (Franzluebbers et al 2000). The effect of grassland on soil C stocks is related to its intensive root cycling system, which has great content of lignin (Martens 2000).…”

Microcalorimetric evaluation of soil microbiological properties under plant residues and dogmatic water gradients in Red soil

“…Changes in moisture levels affect microbial and biotic activity (Bronick et al 2005). Treatments having RS as an organic amendment showed less sudden decreases with the passage of incubation time than did those with GM, since organic amendments with higher rates of decomposition caused rapid but transient effects (Kay 1998) while slower decomposing organic inputs had subtler but longer-lived effects on soil properties (Martens 2000).…”

Influence of Agricultural Wastes and Incubation Period on Aggregate Stability in Sandy Soil

“…MWD, C r , and WAS values between 28 and 42 days decreased probably due to increasing substrate demands of bacteria in soils and bacterial attack on products which bind soil particles together reduces stability. Improved aggregate stability by addition of organic residue to soils is a result of released plant phenolic acid interactions during the decomposition of residues structural components and increasing microbial activity due to carbohydrates metabolisms (Martens, 2000). Polynomial function brought higher correlations between MWD and C r vs. the incubation period of sandy soil mixed with different agriculture organic wastes (Table.…”