Plant controls on decomposition rates: the benefits of restoring abandoned agricultural lands with native prairie grasses

Abstract

Plant species can both directly and indirectly affect soil processes in various ways, including through functional traits related to the quantity and chemistry of biomass produced. Understanding how functional traits affect soil processes may be particularly important in restorations that specifically select a target plant community. In this study, I examined how species differing in litter traits alter decomposition, both directly via chemistry and indirectly via influences on soil microclimate. Decomposition dynamics of two old-field grasses were compared with the native prairie grass, Andropogon gerardii, in two Michigan old-fields. Decomposition rates were strongly, negatively related to tissue chemistry, but showed little effect of microclimate differences. Soil bacterial community composition differed between species at one site, while extracellular enzyme activities differed between species at the other site. These findings suggest plant species may be altering microbial community function. Overall, litter chemistry was the dominant factor determining decomposition rates, suggesting that restoring native prairie grasses with recalcitrant litter into grass-dominated old-fields could slow litter decomposition and ultimately lead to changes in soil carbon and nitrogen cycling. Eventually, this could lead to soils that more closely resemble the more organic-rich soils of native prairies and ultimately increase prairie plant community restoration success.

Does topsoil accelerate the decomposition of litter on roadslopes?

“…The results presented in this study suggest that if the objective of the roadslope restoration is to reduce litter accumulation on road verges, the selection of a higher proportion of legumes in the hydroseeding mixture could help to accelerate litter decomposition and hence nutrient cycling (Mahaney, 2010). However, this recommendation may be effective only in the very short-term due to the short-lived prevalence of hydroseeded species on roadslopes and their natural colonization by local pool species (Matesanz et al, 2006;Mola et al, 2011).…”

“…With the influence of soil nutrient quality on litter decomposition revealed as negligible, physico-chemical composition of litter was found to be the major determinant of litter decomposition under similar climatic conditions (Aerts et al, 2003;Manning et al, 2008;Mahaney, 2010). The importance of species selection is thus underscored for the restoration of these poor quality construction scenarios.…”

“…Leaching, fragmentation and chemical alteration of dead organic matter are the main processes involved in the conversion of detritus to CO 2 , mineral nutrients and organic compounds. These processes depend on abiotic parameters such as environmental conditions like temperature and rainfall (Austin and Vivanco, 2006;Austin et al, 2009;Cusack et al, 2009;Butenschoen et al, 2011), the chemical properties or quality of leaf litter (Cornelissen et al, 1999;Moretto et al, 2001;Cornwell et al, 2008;Mahaney, 2010), and to a lesser extent on soil fauna and microbial communities (Robertson and Paul, 2000;Milcu et al, 2008).…”

“…Litter decomposition is influenced by its chemical composition, particularly recalcitrant compounds (Mahaney, 2010). Slow decomposition rates are associated with high tannin and lignin content (Cortez et al, 1996;Hamadi et al, 2000;Cornwell et al, 2008) and a high lignin/N ratio (Shaw and Harte, 2001).…”

Compost Improves Urban Soil and Water Quality

“…In addition to compost, native prairie grasses [18] and forbs [11] have greater rooting depth than normal lawn mixtures. Therefore, our hypothesis was that compost addition, with or without short prairie grasses, would improve soil and environmental quality in urban soils.…”