|Allmaras, Raymond - USDA-ARS RETIRED|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 2001
Publication Date: N/A
Technical Abstract: Our ability to determine the effectiveness of a given farming system to sequester plant carbon (C) is seriously limited by the scarcity of hard field data quantifying root biomass C inputs. To address this data void, corn (Zea mays L.) biomass, both above and below ground, was determined at physiological maturity (R6) in a 20 y tillage-residue management study consisting of three tillages (chisel plow, CH; moldboard plow, MB; and no tillage, NT) where stover was either retained (r) or harvested (h) from the field. Data presented represent biomass production the first year following 6 y of continuous soybean that was preceded by 13 y of continuous corn. Total biomass production ranged from 26.5 Mg/ha for CHr vs. 15.5 Mg/ha for the NTh treatment. Root biomass production was significantly greater (p < 0.1) for the CHr (1.78 Mg/ha) and least for the NTh (1.0 Mg/ha). Averaged across treatments, 58% of the root biomass was in the 0.0 0to 0.075 m depth increment, with 80+% of root biomass contained in the 0.0 to 0.3 m zone. Although not statistically significant, there was a strikingly greater quantity of root biomass contained in the 0.3 to 0.6 m soil layer of the CHr treatment. Interestingly, the lower 0.05 m of stalk averaged 0.54 Mg/ha of biomass - an important component of total biomass that often gets omitted from mass balance computations.