Fe(Ⅲ) fertilization mitigating net global warming potential and greenhouse gas intensity in paddy rice-wheat rotation systems in China

摘要

A complete accounting of net greenhouse gas balance (NGHGB) and greenhouse gas intensity (GHGI) affected by Fe(Ⅲ) fertilizer application was examined in typical annual paddy rice-winter wheat rotation cropping systems in southeast China. Annual fluxes of soil carbon dioxide (CO_2), methane (CH_4) and nitrous oxide (N_2O) were measured using static chamber method, and the net ecosystem exchange of CO_2 (NEE) was determined by the difference between soil CO_2 emissions (Rh) and net primary production (NPP). Fe(Ⅲ) fertilizer application significantly decreased R_H without adverse effects on NPP of rice and winter wheat. Fe(lII) fertilizer application decreased seasonal CH_4 by 27-44%, but increased annual N_2O by 65-100%. Overall, Fe(Ⅲ) fertilizer application decreased the annual NGHGB and GHGI by 35-47% and 30-36%, respectively. High grain yield and low greenhouse gas intensity can be reconciled by Fe(Ⅲ) fertilizer applied at the local recommendation rate in rice-based cropping systems.