东北三省西部春玉米适应气候变化的高产高效灌溉方案分析

【目的】 东北三省是我国重要的商品粮生产基地之一,同时也是对气候变化最敏感的地区,因此明确气候变化背景下东北三省西部干旱区春玉米的适宜灌溉措施,对于当地春玉米高产稳产水资源高效利用有重要意义。【方法】 依据春玉米生长季积温和水分亏缺率k将东北三省春玉米潜在种植区划分为10个气候区,以东北三省西部5个水分亏缺率k>0的气候区为研究区域,基于1981—2017年的气象资料、农业气象观测站春玉米试验数据和土壤资料,对农业生产系统模型（APSIM-Maize）相关参数进行调试并验证其适用性。设置不同灌溉情景,利用验证后的模型模拟各气候区不同灌溉情景下的春玉米产量,结合水分利用效率明确各气候区不同年代的适宜灌溉措施及产量提升幅度。【结果】 （1）近37年（1981—2017年）5个气候区有效积温均呈显著上升趋势,降水量呈下降趋势。从过去37年平均来看,第一和第三气候区降水对春玉米产量的限制程度较小,分别为0—27%和0—9%,通过灌溉对产量提升的贡献较小,但能有效提高产量的稳定性（可使第一气候区产量变异系数由0.24降低到0.11,第三气候区产量变异系数由0.14降低到0.12）;第五、七和九气候区降水对春玉米产量的限制程度较大,分别为27%—69%,15%—35%,31%—51%,灌溉不仅可提升当地玉米产量,同时可使3个气候区的产量变异系数由0.54降低到0.15,0.46降低到0.13,0.65降低到0.13。表明在东北三省西部干旱区通过灌溉能达到高产稳产的目的。（2）第一和第三气候区大部分年代春玉米高产高效适宜灌溉量为40 mm,且灌溉时间对春玉米产量和水分利用效率的影响较小;第五、七和九气候区大部分年代高产高效适宜灌溉量为60—80 mm,3个气候区适宜灌溉时间分别为吐丝到吐丝后20 d、拔节到拔节后10 d、拔节到拔节后10 d。（3）与雨养条件相比,不同气候区适宜灌溉措施条件下增产幅度不同。其中第五、七和九气候区增产幅度较大,年代际变化范围为33%—86%、24%—46%和50%—77%,第一和三气候区增产幅度较小,年代际变化范围为5%—43%和9%—19%。【结论】 东北三省西部地区春玉米适宜灌溉量随纬度的升高呈减少的趋势,适宜灌溉时间随纬度的升高呈推迟趋势,且随年代的推移,气候变暖,各气候区适宜灌溉时间呈提前趋势。与雨养条件相比,各气候区适宜灌溉措施条件下春玉米可增产0—86%,其中第五、七和九气候区增产幅度较第一和第三气候区更大。

Analysis of Suitable Irrigation Schemes with High-Production and High-Efficiency for Spring Maize to Adapt to Climate Change in the West of Northeast China

【Objective】 The three provinces of Northeast China are not only an important grain production commodity in the country, but also the most sensitive areas to climate change. Thus, it is critical to clarify the suitable irrigation schemes for spring maize in arid areas of the west of Northeast China, which may be benefit on spring maize yield and its stability with higher water use efficiency under climate change. 【Method】 Based on the accumulated temperature and water deficit rate (k) during the growing season in 1981-2017, the potential planting areas of spring maize in Northeast China were divided into 10 climate zones (CZs). Five of them (k>0) in the west portion were selected as research areas. With meteorological data, experimental data, and soil data, maize yield potential was assessed by the well-calibrated and validated agricultural production system model (APSIM-Maize) in each CZ under different irrigation scenarios. According to the comprehensive analysis of both yield and water use efficiency, the suitable irrigation measures and the yield increment in different decades in each CZ were identified. 【Result】 (1) In the past 37 years, the water limitation on spring maize yield in CZ1 and CZ3 were less than that in three other CZs, with a range of 0-27% and 0-9%, respectively. Irrigation contributed little to yield increase, but it could improve the yield stability. The coefficient of yield variation reduced from 0.24 to 0.11 in CZ1, respectively, and reduced from 0.14 to 0.12 in CZ3, respectively. In CZ5, CZ7 and CZ9, more water limitation was found on maize yield, with a range of 27%-69%, 15%-35%, and 31%-51%, respectively. Moreover, irrigation also reduced the coefficients of yield variation by 0.39, 0.33 and 0.52 in the three CZs. The results indicated that irrigation could lead to a high and stable maize yield in the arid areas of Northeast China. (2) The suitable irrigation amount was 40 mm, which could produce high spring maize yield with high water use efficiency in CZ1 and CZ3. However, irrigation time had a little influence on the yield and water use efficiency of spring maize. Meanwhile, the suitable irrigation amounts for high yield and high water use efficiency were 60-80 mm in CZ5, CZ7 and CZ9, and the suitable irrigation times were from silking to 20 days after silking, jointing to 10 days after jointing and jointing to 10 days after jointing. (3) Compared with the rain-fed conditions, the yield increments varied in different CZs under suitable irrigation measures, which ranged from 33% to 86%, 24% to 46% and 50% to 77% in CZ5, CZ7 and CZ9, respectively. Lower yield increments were found in CZ1 and CZ3, with ranges of 5% to 43% and 9% to 19%, respectively. 【Conclusion】 The suitable irrigation amount for spring maize decreased with the latitude increased, and the suitable irrigation time delayed with the increased latitude. In addition, the suitable irrigation time in each CZ advanced because of warming climate. Compared with the rain-fed conditions, spring maize yield could be increased by 0-86% under suitable irrigation measures in each CZ. In particular, the yield increments in CZ5, CZ7 and CZ9 were greater than those in CZ1 and CZ3.