Swedish University of Agricultural Sciences, Department of Soil and Environment, Uppsala, Sweden; Agroscope, Department of Agroecology and Environment, Zurich, Switzerland; ETH Zurich, Institute of Agricultural Sciences, Zurich, Switzerland.
University of São Paulo, Department of Soil and Plant Nutrition, Piracicaba, SP, Brazil.
Sci Total Environ. 2018 Jun 1;626:1026-1035. doi: 10.1016/j.scitotenv.2018.01.129. Epub 2018 Feb 19.
Water is the most limiting resource for global crop production. The projected increase of dry spells due to climate change will further increase the problem of water limited crop yields. Besides low water abundance and availability, water limitations also occur due to restricted water accessibility. Soil penetration resistance, which is largely influenced by soil moisture, is the major soil property regulating root elongation and water accessibility. Until now the interactions between soil penetration resistance, root system properties, water uptake and crop productivity are rarely investigated. In the current study we quantified how interactive effects between soil penetration resistance, root architecture and water uptake affect water accessibility and crop productivity in the field. Maize was grown on compacted and uncompacted soil that was either tilled or remained untilled after compaction, which resulted in four treatments with different topsoil penetration resistance. Higher topsoil penetration resistance caused root systems to be shallower. This resulted in increased water uptake from the topsoil and hence topsoil drying, which further increased the penetration resistance in the uppermost soil layer. As a consequence of this feedback, root growth into deeper soil layers, where water would have been available, was reduced and plant growth decreased. Our results demonstrate that soil penetration resistance, root architecture and water uptake are closely interrelated and thereby determine the potential of plants to access soil water pools. Hence, these interactions and their feedbacks on water accessibility and crop productivity have to be accounted for when developing strategies to alleviate water limitations in cropping systems.
水是全球作物生产的最主要限制资源。由于气候变化预计会增加干旱期，这将进一步加剧水资源限制作物产量的问题。除了水的丰度和可用性低之外，由于水资源可获取性受限，也会出现水资源限制。土壤穿透阻力在很大程度上受土壤水分的影响，是调节根系伸长和水分可获取性的主要土壤特性。到目前为止，土壤穿透阻力、根系特性、水分吸收和作物生产力之间的相互作用很少被研究。在当前的研究中，我们量化了土壤穿透阻力、根系结构和水分吸收之间的相互作用如何影响田间的水分可获取性和作物生产力。玉米种植在压实和未压实的土壤上，压实后进行耕作或不耕作，从而产生了具有不同表土穿透阻力的四种处理。较高的表土穿透阻力导致根系较浅。这导致从表土中吸收更多的水分，从而导致表土干燥，进而增加了最上层土壤的穿透阻力。由于这种反馈，根系向更深的土层生长，而在这些土层中本可以获得水分，从而减少，植物生长减少。我们的结果表明，土壤穿透阻力、根系结构和水分吸收密切相关，从而决定了植物获取土壤水分库的潜力。因此，在制定缓解作物系统中水分限制的策略时，必须考虑这些相互作用及其对水分可获取性和作物生产力的反馈。
