TY - JOUR
T1 - Combining automated and manual chambers to provide reliable estimates of N2O emissions in annual and perennial cropping systems
AU - Siddique, Imran Ahammad
AU - Abalos, Diego
AU - Pullens, Johannes Wilhelmus Maria
AU - Larsen, Klaus Steenberg
AU - Jørgensen, Uffe
AU - Lærke, Poul Erik
N1 - Publisher Copyright:
© 2025 The Author(s)
PY - 2025/5
Y1 - 2025/5
N2 - Perennials can produce more biomass and partially replace annual crops. However, environmental benefits of perennials over annuals in terms of nitrous oxide (N2O) emissions have rarely been compared in a long-term field experiment. By combining automatic and manual chamber methods, we aimed to develop reliable N2O estimates from annual and perennial systems. We measured N2O emissions from: i. perennial grass during renovation including spring barley as catch crop (SB/RG); ii. perennial grass-clover mixture (GC); iii. triticale monoculture (Trit). Results showed that cumulative N2O emissions from SB/RG were higher than GC or Trit. The highest emission rate was measured for SB/RG (258.9 µg N2O[sbnd]N m-2 h-1) after fertilization in spring. Increased N2O emissions were also seen for a short period after direct grass seeding in August. For Trit, N2O emissions increased after fertilization in March and ploughing in late September. In GC (fertilized with P and K), there was no N2O peak after grass cutting. Both from manual and automatic chamber systems, “hot moments” of N2O emissions contributed ∼16–79 % of cumulative emissions. By predicting hot moments and scheduling frequent measurements, manual chambers captured most of the N2O dynamics. The results indicated that the hot moments of N2O emissions were better quantified by automatic chambers, while some of the hot moments, for instance, fertilization and ploughing in Trit were accurately captured with manual chambers. Soil nitrate and ammonium were positively associated with N2O emissions, whereas biomass N uptake was negatively associated. We conclude that perennial (GC) is a promising system for high biomass production with low environmental impact. Strategies such as growing spring barley as a catch crop, grass seeding with shallow tillage, and fertilization of newly seeded grass matching crop N demand are needed to reduce the higher risk for N losses.
AB - Perennials can produce more biomass and partially replace annual crops. However, environmental benefits of perennials over annuals in terms of nitrous oxide (N2O) emissions have rarely been compared in a long-term field experiment. By combining automatic and manual chamber methods, we aimed to develop reliable N2O estimates from annual and perennial systems. We measured N2O emissions from: i. perennial grass during renovation including spring barley as catch crop (SB/RG); ii. perennial grass-clover mixture (GC); iii. triticale monoculture (Trit). Results showed that cumulative N2O emissions from SB/RG were higher than GC or Trit. The highest emission rate was measured for SB/RG (258.9 µg N2O[sbnd]N m-2 h-1) after fertilization in spring. Increased N2O emissions were also seen for a short period after direct grass seeding in August. For Trit, N2O emissions increased after fertilization in March and ploughing in late September. In GC (fertilized with P and K), there was no N2O peak after grass cutting. Both from manual and automatic chamber systems, “hot moments” of N2O emissions contributed ∼16–79 % of cumulative emissions. By predicting hot moments and scheduling frequent measurements, manual chambers captured most of the N2O dynamics. The results indicated that the hot moments of N2O emissions were better quantified by automatic chambers, while some of the hot moments, for instance, fertilization and ploughing in Trit were accurately captured with manual chambers. Soil nitrate and ammonium were positively associated with N2O emissions, whereas biomass N uptake was negatively associated. We conclude that perennial (GC) is a promising system for high biomass production with low environmental impact. Strategies such as growing spring barley as a catch crop, grass seeding with shallow tillage, and fertilization of newly seeded grass matching crop N demand are needed to reduce the higher risk for N losses.
KW - Biomass n uptake
KW - Grass-clover
KW - Grassland renovation
KW - Long-term site
UR - http://www.scopus.com/inward/record.url?scp=105001490365&partnerID=8YFLogxK
U2 - 10.1016/j.agrformet.2025.110530
DO - 10.1016/j.agrformet.2025.110530
M3 - Journal article
AN - SCOPUS:105001490365
SN - 0168-1923
VL - 367
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
M1 - 110530
ER -