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Leaf angle across the sorghum canopy is genetically controlled by both common and layer-specific loci, which holds potential for the development of an optimized canopy associated with higher yields.

• Hydrological regime in the reservoir fluctuation zone has been significantly altered.• Grain-size variations are diagnostic for sedimentary stratigraphy differentiation.• Post-dam sedimentation processes were reproduced by chronology determination.• Regular flow regulation controls contemporary seasonal sedimentary dynamics. Since the launch of the Three Gorges Dam on the Yangtze River, a distinctive reservoir fluctuation zone has been created and significantly modified by regular dam operations. Sediment redistribution within this artificial landscape differs substantially from that in natural fluvial riparian zones, due to a specific hydrological regime comprising steps of water impoundment with increasing magnitudes and seasonal water level fluctuation holding a range of sediment fluxes. This study reinterpreted post-dam sedimentary dynamics in the reservoir fluctuation zone by stratigraphy determination of a 345-cm long sediment core, and related it to impact of the hydrological regime. Seasonality in absolute grain-size composition of suspended sediment was applied as a methodological basis for stratigraphic differentiation. Sedimentary laminations with relatively higher proportions of sandy fractions were ascribed to sedimentation during the dry season when proximal subsurface bank erosion dominates source contributions, while stratigraphy with a lower proportion of sandy fractions is possibly contributed by sedimentation during the wet season when distal upstream surface erosion prevails. Chronology determination revealed non-linear and high annual sedimentation rates ranging from 21.7 to 152.1 cm/yr. Although channel geomorphology may primarily determine the spatial extent of sedimentation, seasonal sedimentary dynamics was predominantly governed by the frequency, magnitude, and duration of flooding. Summer inundation by G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o Contents lists available at ScienceDirectScience of the Total Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n v natural floods with enhanced sediment loads produced from upstream basins induced higher sedimentation rates than water impoundment during the dry season when distal sediment supply was limited. We thus conclude that flow regulation manipulates contemporary seasonal sedimentary dynamics in the reservoir fluctuation zone, though little impact on total sediment retention rate was detected. Ongoing reductions in flow and sediment supply under human disturbance may have profound implications in affecting sedimentary equilibrium in the reservoir fluctuation zone. The results herein provide insights of how big dams have disrupted the sediment conveyance processes of large scale fluvial systems.

Sorghum (Sorghum bicolor) is known as a major feedstock for biofuel production. To improve its biomass yield through genetic research, manually measuring yield component traits (e.g. plant height, stem diameter, leaf angle, leaf area, leaf number, and panicle size) in the field is the current best practice. However, such laborious and time-consuming tasks have become a bottleneck limiting experiment scale and data acquisition frequency. This paper presents a high-throughput field-based robotic phenotyping system which performed side-view stereo imaging for dense sorghum plants with a wide range of plant heights throughout the growing season. Our study demonstrated the suitability of stereo vision for field-based three-dimensional plant phenotyping when recent advances in stereo matching algorithms were incorporated.A robust data processing pipeline was developed to quantify the variations or morphological traits in plant architecture, which included plot-based plant height, plot-based plant width, convex hull volume, plant surface area, and stem diameter (semiautomated). These image-derived measurements were highly repeatable and showed high correlations with the in-field manual measurements. Meanwhile, manually collecting the same traits required a large amount of manpower and time compared to the robotic system. The results demonstrated that the proposed system could be a promising tool for large-scale field-based high-throughput plant phenotyping of bioenergy crops. K E Y W O R D Sbioenergy sorghum, high-throughput phenotyping, point cloud processing, stereo vision, yield component traits

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