Nonruminant livestock (e.g. horses, mules, asses) and monogastric livestock (swine) produce lower methane emissions. During the structural reforms, rice crop areas decreased from 14,100 ha in 1988 to 1,417 ha in 1999. There has been a restoration of rice crop areas since 1999, reaching 10,214 ha in 2013. In Bulgaria, rice is produced under the continuously flooded water regime with a season length of 103 days and one harvest per year.