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Soil water is the main water source for plants, which is replenished by rainfall in the water-limited agricultural systems. Quantifying temporal dynamics of water soil deficit and its replenishment by rainfall can evaluate whether soil water meet the water demand for plants. This would provide accurate guide for when and how the irrigation practices conducted. However, this topic has not been deeply elucidated. In this study, soil water content at varied soil depths and precipitation were continuously monitored during two growing seasons in an apple orchard in the Loess Plateau of China. Soil water storage, soil water deficit and replenishment were also quantified. The results showed that soil water content varied temporally due to the impacts of rainfalls. Soil water storage at 0 ~ 200 cm depth ranged from 272.5 mm to 355.6 mm and the degree of soil water deficit ranged from 0.34 to 0.53 correspondingly. Meanwhile, replenishment of soil water by rainfall was 13.00% in 2017 and 9.78% in 2018, respectively. The qualitative relationship between monthly rainfalls and replenishment indicated that soil water was replenished by rainwater only at soil layers shallower than 160 cm. From the temporal dynamics of soil water content and deficit conditions, soil water could meet the water demand at the fruit expanding stage of apple trees. Irrigation measures should be taken to reduce the soil drought stress at this stage. This study provided an effective hydrological basis to improve the irrigation management of orchards and the efficiency of water resource. [ABSTRACT FROM AUTHOR]

We develop a 3‐D isotropic shear velocity model for the Alaska subduction zone using data from seafloor and land‐based seismographs to investigate along‐strike variations in structure. By applying ambient noise and teleseismic Helmholtz tomography, we derive Rayleigh wave group and phase velocity dispersion maps, then invert them for shear velocity structure using a Bayesian Monte Carlo algorithm. For land‐based stations, we perform a joint inversion of receiver functions and dispersion curves. The forearc crust is relatively thick (35–42 km) and has reduced lower crustal velocities beneath the Kodiak and Semidi segments, which may promote higher seismic coupling. Bristol Bay Basin crust is relatively thin and has a high‐velocity lower layer, suggesting a dense mafic lower crust emplaced by the rifting processes. The incoming plate shows low uppermost mantle velocities, indicating serpentinization. This hydration is more pronounced in the Shumagin segment, with greater velocity reduction extending to 18 ± 3 km depth, compared to the Semidi segment, showing smaller reductions extending to 14 ± 3 km depth. Our estimates of percent serpentinization from VS reduction and VP/VS are larger than those determined using VP reduction in prior studies, likely due to water in cracks affecting VS more than VP. Revised estimates of serpentinization show that more water subducts than previous studies, and that twice as much mantle water is subducted in the Shumagin segment compared to the Semidi segment. Together with estimates from other subduction zones, the results indicate a wide variation in subducted mantle water between different subduction segments. Plain Language Summary: This study uses seismic data from the 2018–2019 Alaska Amphibious Community Seismic Experiment and other land stations to image the 3‐D seismic velocity structure of the Alaska subduction zone. The analysis combines constraints from both Rayleigh waves and converted body waves. The results provide insight into the distinct lateral variations observed for many properties of the subduction zone. Thick, low‐velocity forearc crust is found beneath the Kodiak and Semidi segments, which may be related to the higher seismic coupling in these regions. The Bristol Bay Basin has a thin crust with a high velocity lower layer, suggesting a dense mafic lower crust emplaced by the extensional processes that formed the basin. Low velocities in the incoming plate near the trench in the Shumagin segment indicate pronounced mantle hydration, extending to about 18 km below the Moho. Together with estimates from other subduction zones, the results indicate a wide variation in subducted mantle water between different subduction segments. Key Points: Crustal thickness of the inner forearc (35–42 km) generally exceeds that of the volcanic arc, but becomes variable in the Shumagin segmentThe Shumagin segment has more incoming plate mantle hydration than the Semidi segment, aligning with abundant plate bending normal faultsHydration extends to depths of 18 km below the Moho, indicating more water subducts than most previous estimates [ABSTRACT FROM AUTHOR]

The frequency, intensity, and duration of extreme droughts, with devastating impacts on tree growth and survival, have increased with climate change over the past decades. Assessing growth resistance and resilience to drought is a crucial prerequisite for understanding the responses of forest functioning to drought events. However, the responses of growth resistance and resilience to extreme droughts with different durations across different climatic zones remain unclear. Here, we investigated the spatiotemporal patterns in growth resistance and resilience in response to extreme droughts with different durations during 1901–2015, relying on tree‐ring chronologies from 2389 forest stands over the mid‐ and high‐latitudinal Northern Hemisphere, species‐specific plant functional traits, and diverse climatic factors. The findings revealed that growth resistance and resilience under 1‐year droughts were higher in humid regions than in arid regions. Significant higher growth resistance was observed under 2‐year droughts than under 1‐year droughts in both arid and humid regions, while growth resilience did not show a significant difference. Temporally, tree growth became less resistant and resilient to 1‐year droughts in 1980–2015 than in 1901–1979 in both arid and humid regions. As drought duration lengthened, the predominant impacts of climatic factors on growth resistance and resilience weakened and instead foliar economic traits, plant hydraulic traits, and soil properties became much more important in both climatic regions; in addition, such trends were also observed temporally. Finally, we found that most of the Earth system models (ESMs) used in this study overestimated growth resistance and underestimated growth resilience under both 1‐year and 2‐year droughts. A comprehensive ecophysiological understanding of tree growth responses to longer and intensified drought events is urgently needed, and a specific emphasis should be placed on improving the performance of ESMs. [ABSTRACT FROM AUTHOR]