Abstract This study is to evaluate the BMPs in the reduction of surface discharge and mineral nitrogen yield from paddy cultivation for three future time slices (e.g., the 2010s, 2040s, and 2070s) using APEX-Paddy (Agricultural Policy/Environmental eXtender-Paddy) model. The model was calibrated and validated for surface discharge and mineral nitrogen yield using 3-year monitoring data (2013–2015) from the conventional paddy management field (CMP-1). For surface discharge and mineral nitrogen yield estimates, the future projections of 29 GCMs (General Circulation Model) were bias-corrected and applied to the calibrated APEX-Paddy model. We investigated five specific management strategies related to paddy drainage outlet regulation and new fertilization methods, as the BMPs minimize the mineral nitrogen yield and surface discharges due to climate change. The modeling results indicated that the effects of BMPs would vary by future climate scenarios (i.e., RCP4.5, RCP8.5) and periods (i.e., the 2010s, 2040s, 2070s). It was generally expected that the surface discharge and mineral nitrogen yields would increase in the future. The combination of raising drainage outlets and soil test-based fertilization (DOR-STF) showed a substantial reduction in surface discharge in both scenarios (RCP4.5 and 8.5); the highest reduction rate was observed in the 2010s and was estimated at 21.9 % under RCP4.5. Soil test-based fertilization (STF) showed a substantial reduction in mineral nitrogen yield by 31.0 and 28.3 % during the 2010s under RCP8.5 and RCP4.5, respectively followed by DOR-STF, as compared to conventional management practice (CMP-1). However, the combination of drainage outlet raising, and fertilizer application before outlet weir installation (DOR-FABWI) management resulted in increased mineral nitrogen yield of up to 31.0 % under RCP4.5 and 36.7 % under RCP8.5. The study findings indicate that climate change will increase exports of mineral nitrogen from paddy fields. Nevertheless, appropriate BMPs may play a vital role in reducing the mineral nitrogen yields for the production of paddy rice in future climates, and these effects may vary according to future climate conditions.

中文翻译：

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使用APEX-稻田模型预测未来气候下管理措施对稻田排放和矿质氮产量的影响

摘要 本研究将使用 APEX-Paddy（农业政策/环境扩展-稻谷）评估 BMP 在未来三个时间片（例如，2010 年代、2040 年代和 2070 年代）稻田种植减少地表排放和矿质氮产量方面的作用。模型。使用来自传统稻田管理领域 (CMP-1) 的 3 年监测数据 (2013-2015) 校准和验证模型的地表排放和矿物氮产量。对于地表排放和矿物氮产量估计，对 29 个 GCM（一般循环模型）的未来预测进行了偏差校正，并应用于校准的 APEX-Paddy 模型。我们调查了与水稻排水口调节和新施肥方法相关的五种具体管理策略，因为 BMP 最大限度地减少了由于气候变化引起的矿物氮产量和地表排放。建模结果表明，BMP 的影响将因未来气候情景（即 RCP4.5、RCP8.5）和时期（即 2010 年代、2040 年代、2070 年代）而异。普遍预期未来地表排放和矿物氮产量将增加。在两种情况下（RCP4.5 和 8.5），提高排水口和基于土壤测试的施肥 (DOR-STF) 的结合显示出地表排放量大幅减少；最高的减少率出现在 2010 年代，在 RCP4.5 下估计为 21.9%。基于土壤测试的施肥 (STF) 显示，在 2010 年代，在 RCP8.5 和 RCP4.5 下，矿物氮产量分别显着降低了 31.0% 和 28.3%，其次是 DOR-STF，与传统管理实践 (CMP-1) 相比。然而，排水口抬高和出口堰安装前施肥 (DOR-FABWI) 管理相结合导致矿质氮产量在 RCP4.5 下增加了 31.0%，在 RCP8.5 下增加了 36.7%。研究结果表明，气候变化将增加稻田矿物氮的出口。尽管如此，适当的 BMP 可能在降低未来气候下水稻生产所需的矿物氮产量方面发挥重要作用，这些影响可能会根据未来的气候条件而有所不同。7% 低于 RCP8.5。研究结果表明，气候变化将增加稻田矿物氮的出口。尽管如此，适当的 BMP 可能在降低未来气候下水稻生产所需的矿物氮产量方面发挥重要作用，这些影响可能会根据未来的气候条件而有所不同。7% 低于 RCP8.5。研究结果表明，气候变化将增加稻田矿物氮的出口。尽管如此，适当的 BMP 可能在降低未来气候下水稻生产所需的矿物氮产量方面发挥重要作用，这些影响可能会根据未来的气候条件而有所不同。