Organic-substitute strategies reduced carbon and reactive nitrogen footprints and gained net ecosystem economic benefit for intensive vegetable production

Abstract

Partially substituting inorganic fertilizer with organic fertilizer is widely adopted to improve intensive vegetable production as well as potentially reduce carbon (C) and reactive nitrogen (Nr) footprints, but the associated comprehensive evaluations with life-cycle assessment (LCA) from environmental and economic perspectives have rarely been executed. Covering one-year consecutive vegetable crops rotation, five fertilization strategies were established at an equal N level (SN: single inorganic fertilization; SM: single organic fertilization; mixing organic and inorganic N fertilizer at the ratio of 1:2 (M1N2), 1:1 (M1N1) and 2:1 (M2N1)) and a CK as control. Compared with the SN strategy, the M1N2, M1N1 and M2N1 strategies significantly decreased N2O emission (32.2–50.0%), NO emission (41.8–52.5%), NH3 volatilization (17.8–22.2%), N runoff (29.7–35.3%) and N leaching (34.2–44.8%) as well as significantly increased vegetable yield (4.3–7.4%) and annual SOC sequestration (244.5–463.1 kg C ha−1 yr−1). Consequently, the three organic-substitute strategies significantly reduced C footprint (17.0–21.8%) and the field interface Nr footprint (34.1–43.0%). The production of both organic and inorganic N fertilizer (31.1–51.5%) and N2O emissions (19.9–35.1%) were the hotspots of GHG emissions. The production of organic fertilizer dominated their foreground interface Nr footprint (86.6–97.9%) and environmental damage costs (EDC, 48.6–71.0%), while N leaching dominated the field interface Nr footprint (45.1–50.0%). Therefore, the substitute strategies improved the net ecosystem economic benefits (NEEB, which integrated net economic benefit and EDC) by CNY 2,799−12,151 ha−1 yr−1 and the M2N1and M1N1 strategies produced better NEEB, highlighting that appropriate substitute fertilization strategies are recommended for simultaneously environmental and economic benefits in intensive vegetable production in China.