Effect of controlled-release fertilizer on mitigation of N₂O emission from paddy field in South China: a multi-year field observation

Aim There is an ongoing discussion of potential effect of controlled-release fertilizer (CRF) on nitrous oxide (N₂O) emission from paddy fields. Method A four-year field experiment was launched in a major rice cultivation region of China in 2008 and completed in 2011 to explore effects of CRF on N₂O emissions from paddy fields. The experimental field followed a water regime pattern typical of China, that is, flooding, mid-season aeration (MSA), reflooding and drying-wetting alternation in sequence. Three treatments, i.e. Treatment CK (no N-fertilizer applied), Treatment U (urea applied), and Treatment C (CRF applied), were laid out in a randomized block design. Results Over the 4 years, the estimated average of N₂O emissions during the rice seasons were 19.5±5.5, 81.4±17.8 and 69.6±18.7 mg N m⁻² in Treatments CK, U and C, respectively. On average, CRF reduced N₂O emissions by 13 % and grain yields by 5 %, too, when compared to urea. With normal MSA, Treatment C was 50 %, 11 %, and 25 % lower in N₂O emission than Treatment U in 2009, 2010 and 2011 N ( N normal aeration) (p