Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 2003
Publication Date: November 6, 2003
Citation: OLK, D.C. DOES ANAEROBIC DECOMPOSITION OF CROP RESIDUES ALTER NUTRIENT CYCLING AND SOIL ORGANIC MATTER QUALITY?. ASA-CSSA-SSSA PROCEEDINGS. 2003. CD-ROM. MADISON, WI. ASA-CSSA-SSSA. Technical Abstract: Decomposition of plant residues is anaerobic in wetlands and fields of irrigated lowland rice. Anaerobic decomposition can also be promoted under no-tillage of corn in temperate regions and in low-lying parts of fields planted to upland crops, i.e., pothole soils. Inhibited nutrient cycling has been reported for each of these situations, especially for nitrogen but also for copper and zinc. These specific nutrients share the tendency for chemical stabilization by organic ligands under laboratory conditions. Hence the question arises whether anaerobic decomposition under field conditions promotes chemical stabilization of certain soil nutrients by decomposing plant materials or new organic matter. Here will be summarized evidence for nutrient deficiencies associated with anaerobic decomposition in tropical continuous rice (Philippines), subtropical rice-wheat rotation (Japan), temperate continuous rice (Arkansas), and temperate no-till corn (U.S. Midwest). One mechanistic explanation is that lignin molecules of incorporated plant residues decompose slowly enough under anaerobic conditions so that they chemically bind organic N or these inorganic cations. Release of such bound nutrients into plant-available forms will be inhibited as long as the soil remains flooded and aerobic microbial degradation of the lignin molecules is precluded.