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United States Department of Agriculture

Agricultural Research Service

Title: Soil Biological and Chemical Properties in Restored Perennial Grassland in California

Authors
item Potthoff, Martin - UNIV GOETTINGEN GERM
item Jackson, Louise - LAWR, UC DAVIS
item Steenwerth, Kerri
item Ramirez, Irenee - LAWR, UC DAVIS
item Stromberg, Mark - UC BERKELEY
item Rolston, Dennis - LAWR, UC DAVIS

Submitted to: Restoration Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2005
Publication Date: March 1, 2005
Citation: Potthoff, M., Jackson, L.E., Steenwerth, K.L., Ramirez, I., Stromberg, M.R., Rolston, D.E. 2005. Soil biological and chemical properties in restored perennial grassland in california. Restoration Ecology. 13: 61-73.

Interpretive Summary: Restoration of California native perennial grassland is often initiated with cultivation to reduce the density and cover of non-native annual grasses before seeding with native perennials. Tillage can adversely impact soil quality, thus changes in soil biological functions may also be negatively affected by these restoration techniques. We investigated a restored perennial grassland in the third year after planting Nassella pulchra, Elymus glaucus and Hordeum brachyantherum ssp. californicum for attributes related to soil quality. These include soil chemical characteristics, microbial biomass and respiration, soil organic matter decomposition and CO2 production, and root distribution (0-15, 15-30, 30-60 and 60-80 cm depths). A comparison was also made between untreated annual grassland and plots without plant cover still maintained by tillage and herbicide. In this case, results indicate that soil biological properties (i.e., microbial biomass and respiration) can recover from the intensive tillage and herbicide applications involved when restoring a non-native stand of annual grasses to native perennial grassland dominated by perennial bunchgrasses.

Technical Abstract: Restoration of California native perennial grassland is often initiated with cultivation to reduce the density and cover of non-native annual grasses before seeding with native perennials. Tillage can adversely impact soil quality, thus changes in soil biological functions may also be negatively affected by these restoration techniques. We investigated a restored perennial grassland in the third year after planting Nassella pulchra, Elymus glaucus and Hordeum brachyantherum ssp. californicum for total soil C and nitrogen (N), microbial biomass C, microbial respiration, CO2 concentrations in the soil atmosphere, surface efflux of CO2 and root distribution (0-15, 15-30, 30-60 and 60-80 cm depths). A comparison was made between untreated annual grassland and plots without plant cover still maintained by tillage and herbicide. In the uppermost layer (0-15 cm depth), total C, microbial biomass C (MBC), and respiration were lower in the tilled, bare soil than the grassland soils, as was CO2 efflux. Root length near perennial bunchgrasses was lower at the surface and greater at lower depths than in the annual grass-dominated areas; root biomass had a similar but less pronounced trend. Few differences in soil biological or chemical properties occurred below 15 cm depth. In plots without vegetation, CO2 concentration in the soil atmosphere was lower in plots without vegetation, possibly due to the lack of root respiration. Similar microbiological properties in soil layers below 15 cm depth suggest that deeper microbiota rely on more recalcitrant C sources and are less affected by plant removal than in the surface layer, even after 6 years. Four years after planting native grasses, MBC and activity were nearly the same as the former conditions represented by annual grassland, suggesting high resilience to the temporary disturbance caused by tillage.

Last Modified: 12/18/2014
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