Nitrogen and carbon leaching in agroecosystems and their role in denitrification potential

Citation
Kr. Brye et al., Nitrogen and carbon leaching in agroecosystems and their role in denitrification potential, J ENVIR Q, 30(1), 2001, pp. 58-70
Citations number
41
Categorie Soggetti
Environment/Ecology
Journal title
JOURNAL OF ENVIRONMENTAL QUALITY
ISSN journal
00472425 → ACNP
Volume
30
Issue
1
Year of publication
2001
Pages
58 - 70
Database
ISI
SICI code
0047-2425(200101/02)30:1<58:NACLIA>2.0.ZU;2-P
Abstract
The drainage of water and leaching of dissolved constituents represent majo r components of agroecosystem mass budgets that have been exceedingly diffi cult to measure, Equilibrium-tension lysimeters (ETLs) were used to monitor drainage, nitrogen (N), and carbon (C) leaching through Piano silt loam (f ine-silty, mixed, superactive, mesic Typic Argiudoll) for a 4-yr period in a restored prairie and N-fertilized no-tillage and chisel-plowed maize (Zea mays L.) agroecosystems. Mean drainage recorded during 4 yr fur the prairi e, no-tillage, and chisel-plowed ecosystems totaled 461, 1116, and 1575 mm and represented 16, 33, and 47% of precipitation plus melting of drifted sn ow received, respectively, Total inorganic N leaching losses during the 4-y r period for the prairie, no-tillage, and chisel-plowed ecosystems were 0.6 , 201, and 179 kg N ha(-1), respectively, Inorganic N leaching represented 26 and 24% of applied fertilizer N additions to the no-tillage and chisel-p lowed agroecosystems. Total dissolved C leaching losses were 119, 435, and 502 kg C ha(-1) for the prairie, no-tillage, and chisel-plowed ecosystems, respectively. Sufficient dissolved organic carbon (DOC) and nitrate N (NO3- -N) existed in the prairie and agroecosystems to support subsoil denitrific ation. Potential denitrification, however, was limited by insufficient leng ths of saturated soil conditions in all three ecosystems, the supply of DOC in the agroecosystems, and the supply of nitrate N in the prairie. Based o n available DOC and nitrate N, the maximum contribution of denitrification below the root zone in the agroecosystems was less than 25% of the total am ount of leached nitrate N and the probable contribution of denitrification was much less.