Agricultural & Environmental Letters最新文献

Increasing global food demand combined with more frequent and intense periods of drought necessitates new strategies to improve agricultural water use efficiency. Amending soils with biosurfactants provides a method to increase soil wettability and improve soil water retention, thereby reducing freshwater demand. This study evaluates the impacts of soil texture on soil water retention after amendment with the biosurfactant, surfactin. Texture effects were systematically investigated by mixing silty clay loam soil with Ottawa sand, ensuring chemically equivalent soil constituents. Sandy loam texture exhibited the most significant response after 50 mg kg⁻¹ surfactin treatment, indicated by a 25% water contact angle decrease and a twofold increase in soil water retention after a 48-h dryout period. In contrast, all other soil textures, including silty clay loam, loam, and loamy sand, had no significant improvements. These findings highlight the critical role of soil texture on biosurfactant efficacy for optimized application in agricultural soils.

Core Ideas

Metformin is an anti-diabetic drug that has received increased environmental attention due to probable toxic effects on aquatic ecosystems. Although several studies reported metformin adsorption on soils and minerals, spectroscopic evidence of adsorption mechanisms is limited. Thus, we evaluated metformin adsorption mechanisms on gibbsite and a Tennessee soil (Loring silt loam) using in situ attenuated total reflectance Fourier transform infrared (FTIR) spectroscopy. FTIR results (wavenumber shifts at 1638, 1570, and 1499 cm⁻¹) suggested that 250 µM metformin interacts with soil and gibbsite through the lone pair of electrons on N atoms (N₅, N₆, or N₇ moieties) and delocalized electrons in N₃-N₅-N₆ systems. For soil, metformin may additionally bind via cation exchange in the inter-layer spaces of permanent charge minerals. Direct spectroscopic evidence corroborates earlier studies and provides focus for future investigations to elucidate the fate of metformin at the soil–water interface, depending on different soil physicochemical properties and mineralogy.

Core Ideas

Conflict between agriculture and climate change has long existed, resulting in chronic stresses in farming communities, particularly in low- and middle-income countries (LMICs). This commentary provides an overview of current limitations in plans to address climate change in agriculture of LMICs and suggests modern approaches and integrated solutions to overcome impediments. Five major limitations were identified: lack of reliable climate data, limited technical capacity to predict future climate conditions, limited capacity to design climate-resilient crops, lack of societal awareness of climate injustice, and slow process to identify climate-vulnerable groups in LMICs. Three broad-scale recommendations in the LMIC context could be improved climate monitoring, building capacity for scientific analyses of crop responses to climate stressors at both physiological and molecular levels, and improving climate adaptation with vulnerable farming communities. Integration of state-of-the-art technologies to combat climate injustices is imperative for the agrarian communities of LMICs.

Core Ideas

Chile's agricultural production occurs in a highly variable Mediterranean climate and faces declining annual precipitation trends as well as growing competition from other uses. Water availability for agriculture depends on winter precipitation; however, a more even distribution of precipitation throughout the year would better support agricultural planning and management. We examine the occurrence, frequency, and trends of dry spells in Central Chile (32°–40° S) as a proxy for changes in the timing of dry-wet seasons, using a gridded daily precipitation dataset spanning the period from 1960 to 2021. Our results indicate a significant increase in dry spells (+1 event/decade), but shorter (−2 days/event), and a significant decrease in precipitation per wet spell (−2 mm/event/decade). Findings suggest that changes in dry spells should also be considered in planning and policy, as some regions may be experiencing water shortages due to shifts in timing and access, rather than simply having less water.

Core Ideas

Microplastics are contaminants of global concern that are primarily studied in marine and urban environments. Understanding of microplastics in drained agricultural watersheds is lacking. We aimed to evaluate microplastics in ditch and tile drainage water through periodic sampling. Water samples were filtered to capture particulates that were digested to remove organics, then stained and evaluated using fluorescence microscopy and image analysis. Further, we compared and contrasted microplastic abundance, the current reporting standard, with microplastic mass concentration, often unreported, to determine the most accurate assessment. Open-ditch drainage had greater microplastic contamination than drainpipe outlets. Agricultural drainage contained 2–6 orders of magnitude less mass concentrations of microplastics than sampled urban surface waters and laundry graywater. However, when evaluated by abundance, the difference was not apparent. These findings improve our understanding of microplastics in agricultural watersheds and demonstrate the importance of evaluating microplastic contamination based on mass concentrations for accurate assessments.

Core Ideas