Duck trampling in rice-duck farming alters rice growth and soil CH4 emissions

Abstract

Rice-duck farming utilizes duck activity to mitigate methane (CH4) emissions from paddy fields. Ducks trample the root zone of rice (Oryza sativa L.) and produce vibrations in the soil as they move through the paddy field. This study aimed to determine the response of the CH4 flux, rice growth and microbial community under vibration. Vibration was simulated using a device composed of a motor, rod and wire and was applied in pots at intensities of 9 sec d-1 (V9), 39 sec d-1 (V39), 90 sec d-1 (V90) and 0 (CK). Compared with CK, the CH4 flux at 21 d decreased in V9 and V90, whereas it was unchanged in V39. At 14 d, the CH4 flux in V9, V39 and V90 was 65%, 70% and 35% lower than in CK, respectively. Height and elongation rate of rice reduced in V39 and V90. The dry shoot biomass and the dry root biomass decreased in V90. Compared with CK, the length and surface area of roots in V39 and V90 significantly decreased. The average diameter of roots increased 21% in V39. Root activity increased by 30% and 32% in V9 and V39, respectively. The average well color development increased from 24 h to 120 h in V39. The Shannon, Simpson and evenness indexes increased in all treatments at 120 h. The vibration can decrease the soil CH4 flux, possibly related to the change of rice development and the microbial community.