Climate Change

Biography

Biography: Jing Ma

Abstract

To solve the problem of water shortage, an improved plastic film mulching rice cultivation (PM) has been developed and expanded in recent years in Southwest China. It is a promising alternative to the winter-flooded rice cultivation technology (WF). To explore effects of this technology on CH₄ and N₂O emissions from winter-flooded paddy fields, a field experiment was conducted in Ziyang, Sichuan Province, China from 2012 to 2015. Meanwhile, the effects of nitrification inhibitors (DCD and CP) were estimated. Results showed that annual CH₄ and N₂O emissions from winter-flooded paddy fields ranged from 205-738 kg ha^-1 and 0.05-1.52 kg N ha^-1, respectively. Shifting the fields from WF to PM led to significant reduction 30-76% of CH₄ emissions and 24-70% of 100-year GWP (CH₄+N₂O) though substantial increase of N₂O emissions (10-3975%). Decrease in CH₄ emissions was ascribed to the reduced CH₄ production potential while N₂O emissions were increased as a consequence of more suitable soil water content and single basal application of nitrogen fertilizer in plastic film mulching rice fields. Integrated assessments showed that PM relative to WF significantly enhanced the net ecosystem economic budget (NEEB: balance between the economic benefits: yield gains and input costs; and environmental costs: GWP costs), due to the input costs reduced greatly. If WF was all changed to PM in Sichuan Province, China, the mitigation of 0.53-3.89 Tg CO₂-eq yr^-1 in 100-year GWP (CH₄+N₂O) and the increase of 1.60-3.32 billion CNY yr⁻¹ in NEEB might be achieved. Applying CP under PM conditions reduced 1-10%CH₄emissions and 9-26%N₂O emissions and increased 1-5% grain yields, thus mitigating 6-10% 100-year GWP (CH₄+N₂O) and enhancing 29% NEEB. The results demonstrate that PM and PM+CP increased economic incomes and decreased environmental costs of the fields, which would be the effective management strategies in the regions where are water scarcity.