未来气候变化下有机无机肥配施与灌溉对西南地区水稻产量和土壤养分的影响

Effects of Combined Organic‑inorganic Fertilization and Irrigation on Rice Yield and Soil Nutrients in Southwest China under Future Climate Change

摘要:

气候变化情景下，通过优化水肥管理措施以缓解气候变化对西南地区水稻生产的负面影响，可为该区域水稻生产的可持续性提供理论依据。本研究利用APSIM?ORYZA模型模拟分析了未来SSP2?4.5和SSP5?8.5气候情景下，不同灌溉模式（常规淹灌（CK）与控制灌溉（I1、I2、I3，下限为土壤有效含水率的50%、70%、90%，上限为田间持水量））和有机无机肥配施（20%（F1）、40%（F2）、60%（F3）有机肥替代）对西南地区水稻产量、土壤有机碳和全氮的影响。结果表明，未来不同气候变化情景对西南地区水稻产量具有负面影响，但随着灌溉水量增加减产率降低。相较于历史基准期，未来2050s SSP2?4.5情景I1、I2、I3和CK处理水稻产量分别减少6.9%、5.8%、5.7%和5.3%;至2080s，CK减产率上升至8.7%，I1~I3处理分别上升至10.1%、9.1%、8.9%。此外，控制灌溉处理水稻产量总体由大到小依次为I3、I2、I1，均低于CK，且不同灌溉模式对土壤有机碳影响不大。但未来2080s SSP5?8.5情景，I3处理云南省水稻产量与淹水灌溉产量持平。随着有机肥替代比例增加水稻产量呈先增加后减少趋势。相较于常规施肥量，在SSP2?4.5情景下，F1和F2处理水稻产量分别增加91 kg/hm2和27 kg/hm2，F3处理减少232 kg/hm2;SSP5?8.5情景下，F1和F2处理水稻产量分别增加97 kg/hm2和43 kg/hm2，而F3处理减少155 kg/hm2。且未来不同气候变化情景下，有机肥替代可显著提升西南地区水稻土壤有机碳和全氮含量。未来SSP2?4.5（SSP5?8.5）气候情景下，F1、F2和F3处理2050s土壤有机碳含量分别为209（213）、347（336）、346（355） kg/hm2，相较于CK分别增加71（80）、209（203）、208（222） kg/hm2;F1、F2和F3处理2080s土壤有机碳含量分别为318（323）、554（533）、523（541） kg/hm2，相较于CK分别增加159（167）、395（376）、364（385） kg/hm2。水肥耦合处理下，F1I3处理增产效果最优，较常规水肥管理，该组合在SSP2?4.5情景增产45~186 kg/hm2，SSP5?8.5情景增产38~185 kg/hm2。研究结果表明适度的水肥协同管理可在未来气候变暖背景下有效提升西南地区水稻产量并改善土壤肥力，促进农业生产可持续发展。

Abstract:

Under climate change scenarios, optimizing water and fertilizer management measures to mitigate the negative impacts of climate change on rice production in Southwest China can provide a theoretical basis for the sustainability of rice production in this region. The APSIM?ORYZA model was used to simulate and analyze the impacts of different irrigation modes (conventional flooding irrigation (CK) and controlled irrigation (I1, I2, I3, with lower limits of 50%, 70%, and 90% of the soil available moisture content and upper limits of the field capacity)) and combined application of organic and inorganic fertilizers (20% (F1), 40% (F2), 60% (F3) organic fertilizer substitution) on rice yield, soil organic carbon, and total nitrogen in Southwest China under the future SSP2?4.5 and SSP5?8.5 climate scenarios. The results showed that different future climate change scenarios had negative impacts on rice yield in Southwest China, but the yield reduction rate was decreased with the increase in irrigation water volume. Compared with the historical baseline period, in the 2050s under the SSP2?4.5 scenario, the rice yields of the I1, I2, I3, and CK treatments were decreased by 6.9%, 5.8%, 5.7%, and 5.3%, respectively;by the 2080s, the yield reduction rate of the CK treatment was increased to 8.7%, and those of the I1~I3 treatments were increased to 10.1%, 9.1%, and 8.9%, respectively. In addition, the rice yields of the controlled irrigation treatments were generally decreased in the order of I3, I2, I1, all of which were lower than that of the CK, and different irrigation modes had little impact on soil organic carbon. However, in the 2080s under the SSP5?8.5 scenario, the rice yield of the I3 treatment in Yunnan Province was equal to that of the flooding irrigation. With the increase in the organic fertilizer substitution ratio, the rice yield was firstly increased and then decreased. Compared with the conventional fertilization rate, under the SSP2?4.5 scenario, the rice yields of the F1 and F2 treatments were increased by 91 kg/hm2 and 27 kg/hm2, respectively, while that of the F3 treatment was decreased by 232 kg/hm2;under the SSP5?8.5 scenario, the rice yields of the F1 and F2 treatments were increased by 97 kg/hm2 and 43 kg/hm2, respectively, while that of the F3 treatment was decreased by 155 kg/hm2. Moreover, under different future climate change scenarios, organic fertilizer substitution could significantly increase the soil organic carbon and total nitrogen contents of rice in Southwest China. Under the future SSP2?4.5 (SSP5?8.5) climate scenario, the soil organic carbon contents of the F1, F2, and F3 treatments in the 2050s were 209 (213) kg/hm2, 347 (336) kg/hm2, 346 (355) kg/hm2 respectively, which were increased by 71 (80) kg/hm2, 209 (203) kg/hm2, 208 (222) kg/hm2, respectively compared with that of CK;the soil organic carbon contents of the F1, F2, and F3 treatments in the 2080s were 318 (323) kg/hm2, 554 (533) kg/hm2, 523 (541) kg/hm2, respectively, which were increased by 159 (167) kg/hm2, 395 (376) kg/hm2, 364 (385) kg/hm2, respectively compared with that of CK. Under the water?fertilizer coupling treatment, the F1I3 treatment had the best yield?increasing effect. Compared with the conventional water and fertilizer management, this combination increased the yield by 45~186 kg/hm2 under the SSP2?4.5 scenario and by 38~185 kg/hm2 under the SSP5?8.5 scenario. The research result showed that moderate coordinated water and fertilizer management can effectively increase rice yield and improve soil fertility in Southwest China under the background of future climate warming, promoting the sustainable development of agricultural production.