Sugarcane is a multifunctional crop mainly used for sugar and renewable bioenergy production. Accurate and timely estimation of the sugarcane yield before harvest plays a particularly important role in the management of agroecosystems. The rapid development of remote sensing technologies, especially Light Detecting and Ranging (LiDAR), significantly enhances aboveground fresh weight (AFW) estimations. In our study, we evaluated the capability of LiDAR mounted on an Unmanned Aerial Vehicle (UAV) in estimating the sugarcane AFW in Fusui county, Chongzuo city of Guangxi province, China. We measured the height and the fresh weight of sugarcane plants in 105 sampling plots, and eight variables were extracted from the field-based measurements. Six regression algorithms were used to build the sugarcane AFW model: multiple linear regression (MLR), stepwise multiple regression (SMR), generalized linear model (GLM), generalized boosted model (GBM), kernel-based regularized least squares (KRLS), and random forest regression (RFR). The results demonstrate that RFR (R² = 0.96, RMSE = 1.27 kg m⁻²) performs better than other models in terms of prediction accuracy. The final fitted sugarcane AFW distribution maps exhibited good agreement with the observed values (R² = 0.97, RMSE = 1.33 kg m⁻²). Canopy cover, the distance to the road, and tillage methods all have an impact on sugarcane AFW. Our study provides guidance for calculating the optimum planting density, reducing the negative impact of human activities, and selecting suitable tillage methods in actual cultivation and production.

Understanding the changes in regional droughts is important for promoting overall sustainable development. However, the spatiotemporal dynamics of soil droughts in Guangxi under the background of global warming and regional vegetation restoration have not been studied extensively, and the potential causes are scarcely understood. Here, using TerraClimate soil moisture data, we constructed a monthly standardized soil moisture index (SSMI), analyzed the seasonal and annual spatiotemporal distribution of droughts from the perspective of soil moisture, and studied past soil drought events in Guangxi. Migration methods of drought centroid, trend analysis, and principal component decomposition were used. In the interannual dynamics, the overall SSMI increased, indicating that the soil drought situation was gradually alleviated in Guangxi. Further, the frequency of extreme and severe droughts decreased with time, mainly in autumn and winter. During early drought stages, the migration path was short, which extended as the droughts progressed. Ocean temperature and soil moisture were strongly correlated, indicating that abnormal ocean surface temperature may drive soil moisture. This study provides scientific guidance for the early warning, prevention, and mitigation of losses associated with soil droughts in Guangxi and serves as valuable reference for understanding the impacts of large-scale climate anomalies on soil moisture.

Vegetation plays a vital role in the terrestrial ecosystem. Vegetation variations not only result from climatic and environmental change but also feed back to the climate through biogeochemical and biogeophysical processes. Previous studies have mainly focused on the influence of environmental factors on vegetation changes, but the interactions between vegetation and the prevalent environmental factors in the karst areas of southwestern China have been poorly understood. Based on remote sensing data, this study used trend analysis and Granger causality analysis to investigate vegetation trends, the driving factors, and their interactions during the period 2001 to 2021. In summary, we explored how these factors influenced vegetation growth and how vegetation changes fed back to produce ecosystems and environmental variations in southwestern China during this period. The results showed improvements in water conditions as well as a vegetation greening trend in most of the regions of southwestern China, together with a weakening trend of rocky desertification and an increasing trend of vegetation growth during the period. Both terrestrial water storage and vegetation growth in the energy-limited alpine regions are sensitive to temperature. Natural restoration is suggested in this area. Vegetation growth in the karst areas is sensitive to water stress-related variables due to the particular geological and soil characteristics. The bidirectional causality relationship between vegetation greening and the environment factors in many of these areas indicates that the vegetation changes can also significantly affect water balance and conditions. Ecological engineering projects are suggested in this area. The vegetation growth in the SC Basin, HN, HB, GD, and eastern GX is also sensitive to water stress, while these regions are vulnerable to waterlogging. This study helps to improve our understanding of ecosystem management and promote sustainable development in southwestern China.

Background: Cadmium (Cd) and microplastics (MPs) are gradually increasing in soils, posing a serious threat to humans and crop production. Biochar is a important amendment used worldwide for the remediation of contaminated soils. The role of biochar in mitigating combined Cd and MPs toxicity is rarely studied. Thus, we studied the impact of nano-zinc modified biochar (NZMB) on rice growth, functioning, and productivity in Cd and MPs-co-contaminated soil. Methods: The study has different treatments: control, Cd contaminated soil (20 mg kg ^-1 ), MPs contaminated soil (1%), Cd + MPs contaminated soil, NZMB (2%), Cd contaminated soil (20 mg kg ^-1 ) + NZMB (2%), MPs contaminated soil (1%) + NZMB (2%) and Cd + MPs contaminated soil + NZMB (2%). Results: It was observed that Cd and MPs reduced rice yield (-81%) by impairing chlorophyll synthesis, leaf water contents (-91%), soil nutrient availability, and increasing Cd availability. Biochar application increased the antioxidants activities, osmolyte synthesis, soil organic carbon (+26%), soil pH (18%), nitrogen (+61%), phosphorus (+50%) and potassium availability (40%) and reduced soil Cd availability (-31%), roots Cd (-52%) and shoot Cd (-28%), led to increase in yield in Cd + MPs contaminated soil. Further, NZMB also enhanced the gene expression related to proline ( OsP5CS ), sucrose ( OsSPS1 ), and antioxidants, while decreased expression of gene associated with Cd uptake ( OsNRAMP1 and OsHMA3 ), all of which contributed to an increase in rice yield. Conclusion: This study highlights that NZMB can mitigate the combined Cd and MPs toxicity by decreasing Cd uptake and improving plant functioning. Therefore, these findings will help to develop eco-friendly measures for remediating multi-contaminated soils.