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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #309321

Title: Root traits and soil properties in harvested perennial grassland, annual wheat, and never-tilled annual wheat

Author
item DUPONT, S. TIANNA - Pennsylvania State University
item Beniston, Joshua
item GLOVER, JERRY - Us Agency For International Development (USAID)
item HODSON, AMANDA - University Of California
item CULMAN, STEVEN - University Of California
item LAI, RATTAN - The Ohio State University
item FERRIS, HOWARD - University Of California

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2014
Publication Date: N/A
Citation: N/A

Interpretive Summary: Roots are a key component of plant productivity, but they are among the least studied and understood aspects of agricultural systems. We found that perennial grassland production systems had far greater quantities of roots than annual cropland, and that roots were a key driver of soil properties including carbon and biological food webs in both systems. The results in this study suggest that agricultural systems with larger quantities of roots will support healthier soils.

Technical Abstract: Background and aims: Root functional traits are determinants of soil carbon storage; plant productivity; and ecosystemproperties. However, few studies look at both annual and perennial roots, soil properties, and productivity in the context of field scale agricultural systems. Methods: In Long Termand Conversion studies in North Central Kansas, USA; root biomass and length, soil carbon and nitrogen, microbial biomass, nematode and micro-arthropod communities were measured to a depth of one meter in paired perennial grassland and cropland wheat sites as well as a grassland site that had been converted to cropland using no tillage five years prior. Results: In the Long Term Study root biomass was three to seven times greater (9.4 Mg ha-1 and 2.5 Mg ha-1 in May), and root length two times greater (52.5 km m-2 and 24.0 km m-2 in May) in perennial grassland than in cropland. Soil organic carbon and microbial biomass carbon were larger, numbers of Orbatid mites greater (2084 vs 730 mites m-2), and nematode communities more structured (Structure Index 67 vs 59) in perennial grassland versus annual cropland. Improved soil physical and biological properties in perennial grasslands were significantly correlated with larger, deeper root systems. In the Conversion Study root length and biomass, microbial biomass carbon, mite abundance and nematode community structure differed at some but not all dates and depths. Isotope analysis showed that five years after notill conversion old perennial roots remained in soils of annual wheat fields and that all soil fractions except coarse particulate organic matter were derived from C4 plants. Conclusions: Significant correlation between larger, longer roots in grasslands compared to annual croplands and improved soil biological, physical and chemical properties suggest that perennial roots are an important factor allowing perennial grasslands to maintain productivity and soil quality with few inputs. Perennial roots may persist and continue to influence soil properties long after conversion to annual systems.