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.