Alkaline ameliorants increase nitrous oxide emission from acidified black soil in Northeastern China

Lime and plant ash are common management used to achieve optimum pH for plant growth and improve soil properties in agricultural soils. Laboratory incubation was conducted to assess N 20 emissions as influenced by different soil amendments (lime and plant ash) in a slightly acidic arable soil (pH 5.34). The experimental treatments consisted of CK, lime and plant ash fertilized with NH 4 +-N or N0 3 −-N as nitrogen resource. The results show that lime and plant ash dramatically increases the soil pH and N 20 emission. For N0 3 −-N fertilization, the cumulative N 20 emissions from CK, lime and ash are 421, 1669 and 921 μg N 20-N/kg, respectively. For NH 4 +-N fertilization, the cumulative N 20 emissions from CK, lime and ash are 361, 576 and 559 μg N 20-N/kg, respectively. N0 3 −-N addition leads to more N 20 emission than that of NH 4 +-N addition, and lime increases more N 20 emission than that of plant ash. After incubation, N0 3 −-N content decreased largely. The findings suggested that alkaline ameliorants increase N 20 emissions due to enhancement of soil denitrification.