Methane emission from no-tillage with weed green mulch paddy field

Abstract

Methane emission from paddy soil was compared between conventional (CT) (two sites) and no-tillage with weed green mulch (NTWM) rice paddy in Sakurai City, Nara, Japan. Thick layer (ca. 4cm) with dense fine roots was formed in NTWM paddy, which has been maintained no-tillage for 33-years, whereas soil carbon and nitrogen concentrations were lower in NTWM compared to NT. Methane emission was measured on May, August and September. Biomass of methane oxidizing bacteria (MOB) estimated using phospholipid fatty acid (PLFA) analysis showed that significant negative correlation between MOB and methane emission. Although higher accumulation of organic matter was observed on the soil surface, methane emission from NTWM paddy was smaller than the conventional paddies. Therefore, this NTWM management can be evaluated to provide an important ecosystem services: methane emission reduction in paddy.