|FONTES, GIOVANI - Kansas State University|
|RICE, CHARLES - Kansas State University|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2014
Publication Date: 11/4/2014
Citation: Mikha, M.M., Fontes, G.P., Rice, C.W. 2014. Long term management practices influenced soil aggregation and carbon dynamics [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. p. 202.
Technical Abstract: Soil aggregation protects soil organic C (SOC) against rapid decomposition, improves soil quality, and reduces soil erosion potential. The objectives of this study are to evaluate the effects of long-term (21 yrs.) management practices on SOC, water stable aggregate (WSA), and aggregate-associated C. A study was initiated in 1990 on a moderately well-drained Kennebec silt loam (Fine-silty, mixed, superactive, mesic Cumulic Hapludoll) with continuous corn (Zea mays L.), manure (M) and NH4NO3 fertilizer (F) as the N sources, and no-tillage (NT) and conventional tillage (CT) practices. Soils were incubated for 328 d, sampled in 1990, and 56 d, sampled in 2012, at 35oC at water potential of -0.033 MPa. Periodically, throughout the incubation, soil cores were separated into four aggregate-size classes (> 2000, 250-2000, 53-250, and 20-53 micron) by wet sieving. At the end of the incubation, SOC, at 0- to 5-cm depth, was greatly retained with NT and M treatments. In addition, the prolonged existence of macroaggregates (> 2000 micron) and macroaggregate-associated C were maintained by NT and M treatments. Twenty one years of NT and M practices, show that the longevity of macroaggregates is progressing to achieve the natural ecosystem conditions. Over all, under favorable mineralization conditions, the longevity of soil aggregates, aggregate-associated C, and thus C conservation were more likely sustained by NT, M, and the combination of NT and M management.