Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing, China; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing, China.
Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing, China.
Sci Total Environ. 2016 Apr 15;550:471-483. doi: 10.1016/j.scitotenv.2016.01.148. Epub 2016 Feb 2.
Fertilization and water both affect root water uptake in the nutrient and water cycle of the Soil-Plant-Atmosphere-Continuum (SPAC). In this study, dual stable isotopes (D and (18)O) were used to determine seasonal variations in water uptake patterns of summer maize under different fertilization treatments in Beijing, China during 2013-2014. The contributions of soil water at different depths to water uptake were quantified by the MixSIAR Bayesian mixing model. Water uptake was mainly sourced from soil water in the 0-20cm depth at the seeding (67.7%), jointing (60.5%), tasseling (47.5%), dough (41.4%), and harvest (43.9%) stages, and the 20-50cm depth at the milk stage (32.8%). Different levels of fertilization application led to considerable differences in the proportional contribution of soil water at 0-20cm (6.0-58.5%) and 20-50cm (6.1-26.3%). There was little difference of contributions in the deep layers (50-200cm) among treatments in 2013, whereas differences were observed in 50-90cm at the milk stage and 50-200cm at the dough stage during 2014. The main water uptake depth was concentrated in the upper soil layers (0-50cm) during the wet season (2013), whereas a seasonal drought in 2014 promoted the contribution of soil water in deep layers. The contribution of soil water was significantly and positively correlated with the proportions of root length (r=0.753, p<0.01). The changes of soil water distribution were consistent with the seasonal variation in water uptake patterns. The present study identified water sources for summer maize under varying fertilization treatments and provided scientific implications for fertilization and irrigation management.
施肥和水分都会影响土壤-植物-大气连续体（SPAC）中养分和水分循环的根系吸水。本研究利用双重稳定同位素（D 和 （18）O），结合混合稳定同位素示踪模型（MixSIAR），于 2013-2014 年在北京定位监测了不同施肥处理下夏玉米生育期的水分吸收动态，并探讨了不同施肥处理对土壤水分吸收的影响。结果表明：在播种期（67.7%）、拔节期（60.5%）、抽雄期（47.5%）、乳熟期（41.4%）和收获期（43.9%），夏玉米主要从 0-20cm 土层吸收水分，在灌浆期（32.8%）主要从 20-50cm 土层吸收水分。不同施肥水平导致 0-20cm 土层（6.0-58.5%）和 20-50cm 土层（6.1-26.3%）对水分吸收的贡献存在显著差异。2013 年不同处理间深层（50-200cm）土壤水分的贡献率差异较小，而 2014 年乳熟期 50-90cm 和灌浆期 50-200cm 土层的差异较大。在湿润季节（2013 年），主要根系吸水深度集中在 0-50cm 土层，而 2014 年季节性干旱促进了深层土壤水分的贡献。土壤水分的贡献率与根系长度比例呈显著正相关（r=0.753，p<0.01）。土壤水分分布的变化与夏玉米水分吸收模式的季节性变化一致。本研究为不同施肥处理下夏玉米的水分来源提供了依据，为施肥和灌溉管理提供了科学依据。
