Abdul Kadir

Crop and drought monitoring are vital for sustainable agriculture, as they ensure optimal crop growth, identify stress factors, and enhance productivity, all of which contribute to food security. However, climate projections are equally important as they provide future adaptation scenarios for agriculture. This study aims to project climatic scenarios for northern Bangladesh, assess agricultural and meteorological drought, and estimate crop yield using remote sensing and field data. Our simulated data from 21 CMIP6 models (ensemble mean) under SSP2-4.5 scenarios reveal that maximum temperatures will rise in northwestern regions such as Nawabganj, Rajshahi, Naogaon, Dinajpur, and Joypurhat. By 2050 and 2060, the areas affected by rising mean temperatures are expected to expand into other districts. Additionally, projected rainfall is expected to increase in northern districts, particularly after 2040. Drought assessments using the TOTRAM model reveal a water deficit in many areas in 2022, with milder conditions in 2023. Applying SPEI (Hargreaves-Zamani method) from 1984 to 2024, Sirajganj faced moderately dry conditions (14.38%), while Dinajpur had near-normal conditions (63.33%). Our crop yield model, incorporating Leaf Area Index (LAI), NDVI, SAVI, and field data, demonstrates successful yield estimation, with a significant correlation between predicted and observed yields. The multiple linear regression model achieved a 0.82 goodness-of-fit value, indicating effective yield estimation. We emphasize that timely, accurate information dissemination and monitoring are often more effective in preventing agricultural losses than structural developments. This study encourages decision-makers to integrate geospatial technologies and share critical information with farmers to strengthen food security.

This study aims to assess the impacts of land use and land cover (LULC) changes on the water quality of the Surma river in Bangladesh. For this, seasonal water quality changes were assessed in comparison to the LULC changes recorded from 2010 to 2019. Obtained results from this study indicated that pH, electrical conductivity (EC), and total dissolved solids (TDS) concentrations were higher during the dry season, while dissolved oxygen (DO), 5-day biological oxygen demand (BOD₅), temperature, total suspended solids (TSS), and total solids (TS) concentrations also changed with the season. The analysis of LULC changes within 1000-m buffer zones around the sampling stations revealed that agricultural and vegetation classes decreased; while built-up, waterbody and barren lands increased. Correlation analyses showed that BOD₅, temperature, EC, TDS, and TSS had a significant relationship (5% level) with LULC types. The regression result indicated that BOD₅ was sensitive to changing waterbody (predictors, R² = 0.645), temperature was sensitive to changing waterbodies and agricultural land (R² = 0.889); and EC was sensitive to built-up, vegetation, and barren land (R² = 0.833). Waterbody, built-up, and agricultural LULC were predictors for TDS (R² = 0.993); and waterbody, built-up, and barren LULC were predictors for TSS (R² = 0.922). Built-up areas and waterbodies appeared to have the strongest effect on different water quality parameters. Scientific finding from this study will be vital for decision makers in developing more robust land use management plan at the local level.

The effect of alloy disorder on optical density of states and average room-temperature carrier statistics in Ga1−xInxNyAs1−y quantum wells is discussed. A redshift between the peak of the room-temperature photoluminescence and the surface photovoltage spectra that systematically increases with nitrogen content y is observed. The relationship between this Stokes shift and the absorption linewidth in different samples suggests that the photoexcited carriers undergo a continuous transition—from quasithermal equilibrium with the lattice to complete trapping by quantum dot like potential fluctuations—with increase in nitrogen fraction. The “electron temperatures” inferred from photoluminescence spectra are consistent with this interpretation.