Mingu Zhou

Leaf area index (LAI) is an important indicator of canopy structure and growth status in kiwifruit. To address the high cost of field LAI measurements, limited deep-learning generalization under small-sample conditions, and the lack of quantitative growth-assessment criteria, UAV multispectral imagery and field-measured LAI data from ‘Xuxiang’ kiwifruit orchards in Mei County, China, were integrated to develop an improved ResNet-based LAI retrieval model with an LAI-constrained Mosaic augmentation strategy. The WOFOST crop growth model was parameter-localized using EFAST sensitivity analysis and field observations to simulate multi-year kiwifruit LAI dynamics. A five-level growth assessment system was then established using LAI anomaly percentage. The LAI retrieval model achieved a coefficient of determination (R²) of 0.893, a root mean square error (RMSE) of 0.604, and a mean absolute error (MAE) of 0.447. The localized WOFOST model reproduced LAI dynamics across key phenological stages, with R² values of 0.744–0.821. The stage-specific growth assessment system characterized spatial variation in orchard canopy growth status. Overall, integrating UAV multispectral remote sensing, deep learning, and process-based crop modeling provides a quantitative framework for spatiotemporal monitoring and growth-status assessment in kiwifruit orchards.

To enhance the wear resistance of laser-cladded Ni-WC coatings, recrystallization and stress-relief annealing treatments were applied. The effects of different annealing treatments on the friction performance of the coatings were analyzed using XRD, SEM, and a friction wear tester. The results showed that recrystallization annealing refined the grains and transformed the Ni₄B₃ phase, with the lowest crack rate (10.1%) observed at 800 °C. Stress-relief annealing effectively released residual stress, achieving the lowest crack rate (6.3%) at 500 °C, while promoting the transformation of the Cr₇C₃ phase and improving coating stability. Furthermore, recrystallization annealing was more suitable for enhancing wear resistance, as the coating treated at 800 °C exhibited a lower friction coefficient (0.46) and the smallest wear volume (0.351 mm³). In contrast, stress-relief annealing was more effective in improving hardness, with the coating treated at 500 °C achieving the highest microhardness (936.54 HV1).

Infiltration irrigation with saline water is a more effective method than drip irrigation to alleviate water scarcity worldwide, but so far, no report has discussed the clogging rules of ceramic emitters, a major component of infiltration irrigation system. To explore the clogging mechanism of ceramic emitter in saline water infiltration irrigation system, we used four kinds of saline water sources with electrical conductivity (EC) of 0.18, 1.74, 3.78, and 7.74 ds/m, respectively. In addition, we specifically investigated the law of discharge ratio variation (Dra) of ceramic emitters, as well as the composition and growth process of clogging substance. The results indicated that the Dra of ceramic emitters decreased in the process of saline water irrigation, and the higher the EC, the more obvious the decrease. The calcium carbonate (CaCO₃) was the main component of the clogging substance in the inner wall of ceramic emitters. The clogging part was a layer on the inner wall of the emitters rather than the pores in the walls, and the clogging did not occur suddenly. Instead, it was caused by the long–term accumulation of the clogging substance. Moreover, with the increase of EC, the flocculation between the clogging particles in the water was enhanced and thus promoted the formation of stable and compact aggregates, which fundamentally led to the clogging acceleration of ceramic emitters. This clogging mechanism of ceramic emitters can provide some theoretical reference for the establishment of anti-clogging strategy.