[关键词]
[摘要]
以黑龙江省松嫩平原为研究区,探究不同降水年类型下灌溉对玉米产量和水分利用效率(water use efficiency,EWU)的影响,并制定科学合理的玉米灌溉方案,以提高农业水资源的利用效率。考虑玉米不同生育期和灌水定额的影响,共拟定37种灌溉方案,并将其输入本地化的水作物模型(AquaCrop)中进行模拟分析。探究不同降水年类型下雨养和灌溉对玉米产量、水分利用效率和灌溉水利用效率(irrigation water use efficiency,EIWU)的影响,确定关键灌溉期。通过对不同降水年类型下玉米产量和EWU的对比关系进行分析,确定最优的灌溉制度。结果表明:AquaCrop模型能较好地模拟松嫩平原玉米的生长过程;在玉米关键生育期,适时适量的灌溉能确保作物获得足够的水分,减少产量损失,提高EIWU,但过度灌溉会导致两者降低;综合考虑玉米产量和EWU,在特枯水年,苗期-拔节期(20 mm)、拔节-抽雄期(60 mm)和抽雄-灌浆期(60 mm)为最优灌溉方案;在枯水年,拔节-抽雄期(60 mm)和抽雄-灌浆期(60 mm)为最优灌溉方案,平水年和丰水年降水可以满足玉米水分需求,不需要灌溉。研究可为黑龙江省松嫩平原地区制定更加合理有效的玉米灌溉制度提供相应的理论依据,从而更好地应对气候变化和水资源短缺带来的挑战,保障粮食安全。
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[Abstract]
Sustainable water resource use and food security are fundamental to society's sustainability. Likewise, crop production is a prerequisite for guaranteeing food security. Heilongjiang Province is an essential commercial grain production base in China and has an important strategic position in ensuring national food security. It is located in one of the world's three major soil belts, recognized as the world's golden growth for maize. According to statistics, in 2021, the sown area of maize in Heilongjiang Province was about 652.4×104hm2, accounting for 44.8% of the total sown area of grain in the province, and its output accounted for 37.7% of the national total maize production. The main planting areas of maize in the province are concentrated in the Qiqihar, Suihua, and Harbin regions, which are all in the Songnen Plain region of Heilongjiang Province. However, the region has undergone significant environmental changes due to the trend of aridification, and water scarcity is a severe problem that limits maize growth and development processes. In addition, numerous studies have shown that drought often occurs during the reproductive period of maize and that in dry years, maize production can be increased through scientifically sound irrigation measures, while in years of high-water availability, when precipitation can satisfy maize water demand, care needs to be taken to avoid over-irrigation that leads to wasted water resources and crop damage.Based on 60 years of long-term historical meteorological data, the modified AquaCrop model was used to simulate maize yields under different rain-fed and irrigated scenarios for different precipitation year types at each typical site in the Songnen Plain. Water use efficiency and irrigation water use efficiency were further computed to assess the efficiency of water resource use under different precipitation year types. Finally, the data were spatially interpolated using ArcGIS, and the results were visualized as maps to better understand maize yield and water use in different regions. The results show that in arid years, the irrigation combination of seedling stage - jointing (20 mm), jointing stage - pulling stage (60 mm), and pulling stage - filling stage (60 mm) was the best irrigation scheme. The yield of maize was 11.33 and 10.23 t/hm2, and the average EWU was 2.35 and 2.16 kg/m3, respectively. Irrigation can alleviate the effects of drought on yield. The optimal irrigation scheme in a typical water year was the soxion-filling period (60 mm). Still, the irrigation yield only increased by 0.1 t/hm2, and the average EWU only increased by 0.028 kg/m3. If the seedlings could emerge neatly, irrigation would not be allowed in an average water year. In wet years, precipitation can meet the water demand of maize without irrigation. For normal and wet years, rain-fed agriculture can obtain a similar yield to EWU. Therefore, irrigation strategies should be differentiated according to hydrological years. Irrigation should not be done in wet years to save water resources, and adequate water should be required in dry years, especially in the key growth stages of maize during jointing–pumping, and pumping-filling. In addition, planting dates need to be adjusted to climate change trends to make the most of natural precipitation and reduce irrigation needs. Future studies should comprehensively consider the effects of climate change, soil moisture, and maize variety improvement to provide a theoretical basis for formulating a reasonable and effective maize irrigation system, coping with climate change and water shortage challenges, and ensuring food security. Conclusion: The AquaCrop model can effectively simulate the growth process of maize in the Songnen Plain. During the critical growth stages of maize, timely and appropriate irrigation can ensure the crop receives sufficient water, reduce yield loss, and improve Water Use Efficiency (EWU). However, over-irrigation can lead to a decrease in both. As yields increase,EWU may decline because higher yields may require more water. In arid years, the optimal irrigation schemes are 20 mm from the seedling to the jointing stage, 60 mm from the jointing to the tasseling stage, and 60mm from the tasseling to the filling stage. In dry years, the optimal schemes are 60 mm during the jointing to tasseling stage and 60 mm during the tasseling to filling stage. Precipitation is sufficient in normal and wet years to meet the maize’s water needs. No irrigation is required. This study can provide a theoretical basis for developing a more rational and effective maize irrigation system in the Songnen Plain of Heilongjiang Province, thereby better addressing the challenges of climate change and water scarcity and ensuring food security.
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