Soil Carbon Budget for Annual and Perennial Ryegrass Grown For Seed

Authors: Griffith, Stephen; Davis, Jennifer; Banowetz, Gary

Submitted to: Seed Production Research at Oregon State University
Publication Type: Experiment Station
Publication Acceptance Date: 3/1/2010
Publication Date: 3/31/2010
Citation: Griffith, S.M., Davis, J.H., Banowetz, G.M. 2010. Soil Carbon Budget for Annual and Perennial Ryegrass Grown For Seed. Seed Production Research at Oregon State University. 139:31.

Interpretive Summary: There much interest in carbon (C) sequestration (C accounting) in cropping systems due the potential for agriculture to participate in ‘Cap and Trade’ opportunities, or purely as a matter of understanding soil quality. In addition, soil C is one of the most critical components of soil quality and fertility. In this report we have constructed carbon budgets for two temperate grass species, perennial ryegrass (Lolium perenne L.) and Italian ryegrass (L. multiflorum Lam.). Data were collected from western Oregon grown grass seed crops. We hypothesized that most temperate grass systems grown in western Oregon that are not limited by water or nutrients will have similar C budgets. It has been reported that soil C in grass seed cropping systems, over the long-term, can be affected by crop rotation, tillage, and residue management but usually the effects are minor. Soils of grass seed production systems in western Oregon have high organic C levels, greater than those frequently observed in conventional annual cropping systems that often involve annual soil disturbance for crop establishment. Future reports will construct more precise C budgets with more subcomponents (e.g., longer- vs. shorter-term sequestered C), but these data establish a baseline that will be useful for evaluating C cycling in grass seed production systems.

Technical Abstract: There much interest in carbon (C) sequestration (C accounting) in cropping systems due the potential for agriculture to participate in ‘Cap and Trade’ opportunities, or purely as a matter of understanding soil quality. In this report we have constructed carbon budgets for two temperate grass species, perennial ryegrass (Lolium perenne L.) and Italian ryegrass (L. multiflorum Lam.). Data were collected from western Oregon grown grass seed crops. The range of soil C for these two grass seed crops was approximately 28,000 to 37,000 kg C/ha and soil organic matter ranged from 4.43 to 5.69%. We hypothesized that most temperate grass seed systems grown in western Oregon that are not limited by water or nutrients will have similar C budgets. It has been reported that soil C in grass seed cropping systems, over the long-term, can be affected by crop rotation, tillage, and residue management but usually the effects are minor. Soils of grass seed production systems in western Oregon have high organic C levels, greater than those frequently observed in conventional annual cropping systems that often involve annual soil disturbance for crop establishment. Future reports will construct more precise C budgets with more subcomponents (e.g., longer- vs. shorter-term sequestered C), but these data establish a baseline that will be useful for evaluating C cycling in grass seed production systems.