Nitrous Oxide Eemission Mechanism and Emission Mitigation Measures of Tea Plantation: A Review

Tea plantation has become an important source of agricultural nitrous oxide (N₂O) emission in China due to high N₂O emission factor, high application of nitrogen fertilizer and increasing planting area year by year. In 2013, the total N₂O emission of tea plantations in China was estimated to be 40.90 Gg. Therefore, it is urgent to study the N₂O emission mechanism and effective emission reduction measures of tea plantations. With the deepening of research on N₂O emission process and influencing factors in tea plantations, many summarized emission reduction strategies are regarded as effective measures to mitigate N₂O emission in tea plantations. Through the review, we found that:(1) the N₂O emissionfrom tea plantations is mainly caused by soil nitrification and denitrification, and the later contricutes more; (2) the main factors affecting N₂O emission in tea plantations are meteorological factors (temperature, rainfall) and soil conditions (pH, moisture content, texture, temperature, substrate concentration); (3) effective N₂O emission mitigation measures in tea plantations mainly include the application of ammonium nitrogen fertilizer, controlled release nitrogen fertilizer, lime nitrogen fertilizer and deeply placing of nitrogen fertilizer; (4) there are still different opinions in the N₂O emission reduction effects among applying organic fertilizer, applying biological nitrification inhibitors, adding alkaline materials, adding biomass charcoal, interplanting leguminous and applying biological fertilizers, which need to be further studied. At present, there are many researches on the influence of different agronomic measures on N₂O emission characteristics in tea plantation, but there is no agreement on the effect of N₂O emission reduction.This paper comprehensively analyzes the effect and mechanism of different agronomic measures on N₂O emissionin tea plantation, hoping to provide theoretical and practical references for further research on N₂O emissions mitigation in tea plantation.