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水分条件是直接影响农作物产量高低的主要限制因子之一,但对青海湖流域油菜和燕麦植物水分利用方式的认识尚不清楚。论文收集油菜和燕麦整个生育期内降水、植物和土壤水氢氧稳定同位素组成,并通过直接对比法和多源混合模型定量地计算出油菜和燕麦对不同深度土壤水分利用比例。结果表明:降水中同位素组成表征出较大的波动性变化,浅层土壤水同位素组成受蒸发作用影响明显富集于深层土壤水分,且土壤水中同位素在垂直方向上呈浅层土壤水较富集于深层土壤水。油菜在生育期内根系吸水方式在浅层和深层土壤间发生明显的转换,如在蕾薹期、开花期、灌浆期及成熟期主要依赖于0~10 cm(95.1%)、0~10 cm(68%和44.8%)、30~60 cm(69.9%)及0~10 cm(38.8%)的土壤水分。而燕麦根系吸水范围却没有表征出明显的改变,在整个生育期内土壤水分利用深度在0~30 cm间变化。这将为高寒地区耕作方式调整及发展节水高效的现代农业提供理论依据。
Water conditions are one of the main limiting factors that directly affect the crop yield. However, the understanding of water use patterns of rape and oat plants in the Qinghai Lake Basin is not clear. The paper collects the composition of hydrogen and oxygen stable isotopes of precipitation, plant and soil water during the whole growth period of rapeseed and oats. The ratio of rapeseed and oat to soil water use at different depths is calculated quantitatively by direct contrast method and multi-source mixed model. The results show that the variation of isotopic composition in precipitation is characterized by large fluctuation. The water isotope composition of shallow soil is enriched in deep soil water by evaporation, and the vertical distribution of soil water isotopes is more abundant in shallow soil water In deep soil water. During the growth period, the root water uptake mode of rapeseed obviously changed between shallow soil and deep soil, such as 0-10 cm (95.1%), 0-10 cm at budding, flowering, filling and maturity stages (68% and 44.8%), 30-60 cm (69.9%) and 0-10 cm (38.8%) respectively. However, no significant changes were observed in the water absorption range of oat roots, and the depth of soil water use varied from 0 to 30 cm during the whole growth period. This will provide a theoretical basis for the adjustment of farming practices in the alpine region and the development of modern agriculture that is water-saving and efficient.