TY - JOUR

T1 - Gaseous nitrogen losses from urea applied to maize on a calcareous fluvo-aquic soil in the North China Plain

AU - Cai, G.

AU - Chen, Daolun L.

AU - White, R.E.

AU - Fan, X.H.

AU - Pacholski, Andreas

AU - Zhu, Z.L.

AU - Ding, H.

PY - 2002/1/1

Y1 - 2002/1/1

N2 - Gaseous nitrogen losses, by NH 3 volatilisation and denitrification, are mainly responsible for the low recovery of N fertiliser applied to irrigated maize on the North China Plain. Two field experiments were conducted to measure NH 3 volatilisation and nitrification-denitrification losses from urea applied to maize (Zea mays L.) grown on a calcareous fluvo-aquic soil (Aquic Inceptisol) in Fengqiu County, Henan Province. The first was carried out in June 1998 (urea applied at 75 kg N/ha 3 weeks after sowing), and the second in July 1998 (urea applied at 200 kg N/ha 6 weeks after sowing). Each experiment included 3 treatments - control, surface-broadcast (SB), and deep point placement (DP) or broadcast followed by irrigation (BI). NH 3 loss was measured by a micrometeorological method (NH 3 sampler). Denitrification (N 2 + N 2O) was measured by the acetylene inhibition-intact soil core technique, and N 2O emission was also measured in the absence of acetylene. The recovery of applied N was measured by a 15N balance technique. When urea was surface broadcast (SB) 3 weeks (75 kg N/ha) and 6weeks (200 kg N/ha) after sowing, 44 and 48% of the applied N was lost by NH 3 volatilisation, respectively. The corresponding losses from the BI and DP treatments were only 18% and 11%, respectively. Denitrification was a significant process in this well-drained sandy soil, with average loss rates of 0.26-0.43 kg N/ha.day in the controls (from resident soil N), compared with 0.52-0.63 kg N/ha.day in the surface fertiliser treatments. Deep placement of urea reduced the denitrification rate to an average of 0.3 kg N/ha.day. The net denitrification loss from the fertiliser was <2% of the applied N, except for the SB urea treatment in the second experiment. The application of N fertiliser as urea increased N 2O emissions from c. 0.3 to c. 2.3 kg N/ha over 57 days in the second experiment, with average N 2O emission rates in the control and SB treatment of 0.006 and 0.042 kg N/ha.day, respectively. The significantly lower ratio of N 2/N 2O in the urea treatments compared with the control suggested that nitrification of applied N may have contributed to N 2O production. Alternatively, the ratio of N 2/N 2O during dinitrification may have changed with the greater supply of NO 3 -.

AB - Gaseous nitrogen losses, by NH 3 volatilisation and denitrification, are mainly responsible for the low recovery of N fertiliser applied to irrigated maize on the North China Plain. Two field experiments were conducted to measure NH 3 volatilisation and nitrification-denitrification losses from urea applied to maize (Zea mays L.) grown on a calcareous fluvo-aquic soil (Aquic Inceptisol) in Fengqiu County, Henan Province. The first was carried out in June 1998 (urea applied at 75 kg N/ha 3 weeks after sowing), and the second in July 1998 (urea applied at 200 kg N/ha 6 weeks after sowing). Each experiment included 3 treatments - control, surface-broadcast (SB), and deep point placement (DP) or broadcast followed by irrigation (BI). NH 3 loss was measured by a micrometeorological method (NH 3 sampler). Denitrification (N 2 + N 2O) was measured by the acetylene inhibition-intact soil core technique, and N 2O emission was also measured in the absence of acetylene. The recovery of applied N was measured by a 15N balance technique. When urea was surface broadcast (SB) 3 weeks (75 kg N/ha) and 6weeks (200 kg N/ha) after sowing, 44 and 48% of the applied N was lost by NH 3 volatilisation, respectively. The corresponding losses from the BI and DP treatments were only 18% and 11%, respectively. Denitrification was a significant process in this well-drained sandy soil, with average loss rates of 0.26-0.43 kg N/ha.day in the controls (from resident soil N), compared with 0.52-0.63 kg N/ha.day in the surface fertiliser treatments. Deep placement of urea reduced the denitrification rate to an average of 0.3 kg N/ha.day. The net denitrification loss from the fertiliser was <2% of the applied N, except for the SB urea treatment in the second experiment. The application of N fertiliser as urea increased N 2O emissions from c. 0.3 to c. 2.3 kg N/ha over 57 days in the second experiment, with average N 2O emission rates in the control and SB treatment of 0.006 and 0.042 kg N/ha.day, respectively. The significantly lower ratio of N 2/N 2O in the urea treatments compared with the control suggested that nitrification of applied N may have contributed to N 2O production. Alternatively, the ratio of N 2/N 2O during dinitrification may have changed with the greater supply of NO 3 -.

KW - Ecosystems Research

KW - Denitrification

KW - Maize

KW - N O emission

KW - NH volatilisation

UR - http://www.scopus.com/inward/record.url?scp=0036345393&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/d4d73841-a900-35bd-a1f9-ba54d1ccc5de/

U2 - 10.1071/SR01011

DO - 10.1071/SR01011

M3 - Journal articles

AN - SCOPUS:0036345393

VL - 40

SP - 737

EP - 748

JO - Australian Journal of Soil Research

JF - Australian Journal of Soil Research

SN - 0004-9573

IS - 5

ER -