The optimal timing and allocation of micro-supplemental irrigation, and the root–nitrogen mechanisms linking stage-targeted water inputs

The gap

Evidence profile

Sourced from the future work and abstract of the source papers, classified as general, drawn from work published between 2024 and 2026, spanning 2 journals. Those papers have been cited 23 times in total.

Supporting evidence — 3 representative gaps

• Root system architecture remodeling under oxygen-mediated subsurface drip irrigation: a mechanistic hypothesis framework linking multiphase mass transfer to root foraging decisions (2026) · Frontiers in Plant Science · doi

  4.1 Conclusions SDI has inherent structural trade-offs in the soil pore space: it is quite challenging to simultaneously meet the supply of water and oxygen. This review holds that in the heterogeneous water-oxygen field generated by point source infiltration, the root response may not be fully explained merely by soil moisture distribution or root morphology. From the perspective of the optimal foraging theory, root plasticity under aerated irrigation is more appropriately understood as a spatial investment adjustment, which tracks the changes in foraging metabolic costs. The reconstruction framework proposed in this review lies precisely here: By integrating evidence from root ecology, plant oxygen signaling, and irrigation engineer- ing, we reposition aerated SDI from a purely hydraulic intervention to a framework for managing the location and cost of root resource acquisition. The core proposition - that root zone oxygen availabil- ity not only serves as a growth promoter but also as a variable regulating the metabolic cost of resource acquisition - is proposed here as a testable mechanism hypothesis framework. The existing evidence converges into a coherent mechanism along the path from oxygen perception and signal integration of the physical environment in the root zone to root configuration adjustment: Micro-nano bubbles (MNBs) can alleviate the limitations of water-rich and oxygen-poor conditions on root activity, reduce the physiological cost of foraging, and thereby reshape root configuration and rhizosphere microbial function by increasing the dissolved oxygen concentration around the root tip. We propose this as a mechanism-based explanation mainly based on correlation and dominated by controlled environmental evidence, rather than a closed causal chain. There are still two boundaries to be resolved: the spatiotemporal dynamics of irrigation-induced oxygen fluctua- tions and the field-scale behavior of MNBs in heterogeneous soil. By listing these as open-ended questions, this review transforms descrip- tive narratives into predictions that can be confirmed or refuted. Oxygen mediation is not solely an environmental factor that promotes root growth; however, it is also a key variable regulating the cost and efficiency of root resource acquisition. Accordingly, the optimization target of SDI should transition from increasing soil water coverage alone to optimizing FAD. Additionally, aer- ated irrigation does not need to be defined solely by the synchro- nous supply of water, nutrients, and oxygen; however, it can be reframed around the interactions among roots, soil, water, nutri- ents, oxygen, and the microbiome, together with root behavioral regulation. This perspective may provide a more coherent theo- retical basis for improving water and nutrient use efficiencies in irrigated agriculture. 4.2 Future research directions Future studies should focus along three directions: microscopic mechanisms, cross-scale integration, and macroscale application, and, more specifically, across four levels: decision modeling of rhizosphere ecosystems, functional–structural plant models embed- ded with OFT, climate-adaptive resilience design of irrigation systems, and scale-up and translational pathways. The cost–benefit decision engine of the OFT serves as the central link, providing evidence from microscopic processes to macroscale regulation targets and supporting a smart root-zone regulation system based on a sensing–simulation–feedback loop (Figure 6). 4.2.1 Establishing the causal role of oxygen The most consequential open question is whether oxygen independently drives RSA remodeling or merely co-varies with

  generalfuture work
  Keywords: root oxygen water soil irrigation cost evidence review foraging framework resource acquisition zone mechanism based
• Drip irrigation frequency leads to plasticity in root water uptake by apple trees (2024) · Agricultural Water Management · cited 22× · doi

  This root water uptake plasticity explains the lacking evidence of physiological stress in sap flux records at DI and supports the potential for further improvements of precision irrigation in similar climatic and edaphic settings.

  generalabstractevidence 5/5
  Keywords: root water uptake plasticity explains lacking evidence physiological stress flux records supports potential further improvements
• Stage-targeted micro-supplemental irrigation at jointing and tasseling enhances sorghum yield and nitrogen uptake by optimizing root morphology in semi-arid dryland systems (2026) · Agricultural Water Management · cited 1× · doi

  However, the optimal timing and allocation of micro-supplemental irrigation, and the root–nitrogen mechanisms linking stage-targeted water inputs to yield formation and water use efficiency (WUE), remain insufficiently quantified.

  generalabstractevidence 5/5
  Keywords: water optimal timing allocation micro supplemental irrigation root nitrogen mechanisms linking stage targeted inputs yield

Questions about this gap