To address water scarcity and soil damage in the Hexi Oasis irrigation area of China, a study was conducted on regulating water and nitrogen levels for soybean growth under film drip irrigation over two growing seasons (2020 and 2021). Two irrigation levels were tested: mild deficit (W1, 60-70% of field water capacity, FC) and full irrigation (W2, 70-80% of FC), along with three nitrogen levels: low (N1, 60 kgha-1), medium (N2, 120 kgha-1), and high (N3, 180 kgha-1). The control treatment was no nitrogen with full irrigation (W2N0), totaling seven treatments. Results showed that during both growing seasons, soybean plant height reached its peak at the tympanic ripening stage, while the leaf area index (LAI), net photosynthesis rate (Pn), and transpiration rate (Tr) decreased at the tympanic ripening stage. The highest values for the plant height, LAI, Pn, Tr, yield, and the cost-benefit ratio were observed under the W2N2 treatment, significantly outperforming the W2N0 in all aspects (p < 0.05). Over the two-year period, the plant height and LAI were notably higher by 22.86% and 7.09%, respectively, in the W2N2 treatment compared to the W1N1. Full irrigation under N1 and N2 conditions resulted in an enhanced soybean Pn and Tr. However, under N3 conditions, a deficit-tuned irrigation treatment led to a 15.71% increase in the Pn and a 13.34% increase in the Tr on a two-year average. The W2N2 treatment had the highest yield, with a significant 4.93% increase over the W1N3 treatment on a two-year average. The highest rate of change in yield was observed in W1. The two-year cost-benefit ratio and unilateral water benefit reached their peak values in W2N2 and W1N2, respectively. Water use efficiency (WUE) was lower in N1 but significantly increased by 21.83% on a two-year average in W1N3 compared to W1N2. Additionally, W1 had a 14.21% higher WUE than W2 over two years. N3 had the lowest partial factor productivity of nitrogen, which increased by 17.78% on a two-year average in W2N1 compared to W1N1. All nine indicators related to yield formation and water-nitrogen use efficiency showed a positive correlation (p < 0.05) in this study. The highest composite scores were achieved with the W2N2 treatment in both years using the entropy weight and TOPSIS method. Overall, the W2N2 treatment provides a water and nitrogen combination that enhances soybean water and fertilizer efficiency, making it a promising option for high-yield soybean cultivation with water and nitrogen conservation in the Hexi Oasis irrigation area of China. This study offers valuable insights for achieving efficient soybean production while saving water and reducing nitrogen use.

Urban trees have attracted increasing attention to serve as a green prescription for addressing various challenges facing human society like climate change and environmental deterioration. However, without healthy growth of urban trees, they cannot service any environmental, social, and economic benefits in a sustainable manner. By monitoring the canopy development, the tree growth dynamics in different urban habitats can be detected and appropriate management approaches can be executed. Using the Kowloon Peninsula, Hong Kong, as a case, this study explores how remote sensing data can help monitor and understand the impacts of heterogeneous urban habitats on tree canopy dynamics. Four algorithms based on WorldView-2 satellite image are compared to optimize the canopy segmentation. Then the individual tree canopy is integrated with Sentinel-2 satellite data to obtain canopy growth dynamics for each season from 2016 to 2020. Three indicators are applied to reflect tree canopy status, including the fluorescence correction vegetation index (FCVI, tracking leaf chlorophyll density), the soil adjusted total vegetation index (SATVI, measuring the density of woody branches and twigs), and the normalised difference phenology index (NDPI, capturing canopy water content). And four heterogeneous habitats where urban trees stand are specified. The results revealed that urban trees show varying canopy growth status, in a descending order from natural terrains, parks, residential lands, to road verges, suggesting that urban habitats curtail trees' growth significantly. Additionally, two super-typhoons in 2017 and 2018, respectively, caused serious damages to tree canopy. Relevant resiliency of tree varies, echoing the sequence of canopy growth status with those in road verges the least resilient. This study shows how remote sensing data can be used to provide a better understanding of long-term tree canopy dynamics across large-scale heterogeneous urban habitats, which is key to monitoring and maintaining the health and growth of urban trees.

Wildfires considerably disturb the structure and forest ecosystem functioning. The disturbances estimation as well as the extent of damage to the soil and vegetation soon after the fire is crucial information for planning of restoration efforts. Because of the financial resources needed for field work and the involvement of experts, remote aerospace methods and data are extensively employed in monitoring ecological research. The aim of this paper is to assess postfire forest disturbances and initial regrowth processes using the tasseled cap derived Direction Angle (DA). DA is an index introduced by the authors in previous research - the angle between the Greenness component from the TCT (tasseled cap transformation) and VIC (Vector of Instantaneous Condition). The proposed method is based on linear orthogonal transformation of multispectral satellite images and is characterized with higher accuracy compared to standard methodologies using vegetation indices. The higher accuracy of the methodology is based on the linear orthogonal transformation of multispectral satellite images (TCT), which increases the degree of identification of the three main components changing during fire - soil, vegetation, and moisture/water. The methodology proposed in this paper is characterized by high accuracy in assessing the recovery of undergrowth, that is difficult to differentiate using standard monitoring methodologies based on vegetation indices. The DA raster images show the direction of change of the green tasseled cap component (TCG) relative to the VIC, which allows to estimate the degree of recovery of the vegetation component for different moments of the study period. The variations observed in DA values illustrate the pattern of the green component at various points during the investigation period, enabling the assessment of disturbances and the monitoring of regrowth processes. The test area is located in the Middle Rhodopes, near the village of Hvoyna (Smolyan region), Bulgaria, where on 28/08/2023 a wildfire broke out. 1,500 decares have been burnt by the fire, including deciduous and coniferous forest. The wildfire affected 100-130 years old black pine (Pinus nigra) forests.