Agriculture in highly weathered tropical soils often requires considerable application of lime and fertilizers to ensure satisfactory plant nutrient levels. The consequences of these continue long-term applications is not well understood may induce changes in soil chemical properties, the abundance, and speciation of potentially toxic trace element and as well as of micronutrients in agriculture soils. In this study, we evaluated the adsorption (at pH 5) and speciation of Zn in tropical soils (both agricultural and native vegetation) as a function of fertilization and contact time using chemical fractionation analyses and X-ray absorption spectroscopy. The soils overall had high Zn adsorption capacities (∼ 700 mg kg), but the agricultural soil was approximately 30 % higher than of the soil under native vegetation, and the proportion of Zn in the mobile fraction was 35 % in native vegetation and 21 % in agricultural soils. Zn speciation via linear combination analysis showed a strong relationship with soil mineralogical composition and reveled that Zn associated with organic matter decreased while Zn associated with P increased after the conversion of soils from native vegetation to highly fertilized soil. Aluminosilicate soil minerals were identified as major sinks of soil Zn, accounting for 34 % of total Zn retention regardless of soil origin and land use. Association of Zn with phosphate (i.e., hopeite) was observed in the agricultural soil samples, which might be an unexpected Zn-bearing mineral in highly weathered tropical soils and could have impacts on Zn plant nutrition.
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http://dx.doi.org/10.1016/j.scitotenv.2024.170223 | DOI Listing |
PLoS Negl Trop Dis
January 2025
DeWorm3 Project, Seattle, Washington, United States of America.
Background: Historically, soil-transmitted helminth (STH) control and prevention strategies have relied on mass drug administration efforts targeting preschool and school-aged children. While these efforts have succeeded in reducing morbidity associated with STH infection, recent modeling efforts have suggested that expanding intervention to treatment of the entire community could achieve transmission interruption in some settings. Testing the feasibility of such an approach requires large-scale clinical trials, such as the DeWorm3 cluster randomized trial.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Civil and Environmental Engineering, Nazarbayev University, Nur-Sultan, Kazakhstan.
Rainfall-induced landslides are a frequent geohazard for tropical regions with prevalent residual soils and year-round rainy seasons. The water infiltration into unsaturated soil can be analyzed using the soil-water characteristic curve (SWCC) and permeability function which can be used to monitor and predict incoming landslides, showing the necessity of selecting the appropriate model parameter while fitting the SWCC model. This paper presents a set of data from six different sections of the studied slope at varying depths that are used to test the performance of three SWCC models, the van Genuchten-Mualem (vG-M), Fredlund-Xing (F-X) and Gardner (G).
View Article and Find Full Text PDFSci Adv
January 2025
Department of Geography and Spatial Sciences, University of Delaware, Newark, DE, USA.
Climate change threatens smallholder agriculture and food security in the Global South. While cropland expansion is often used to counter adverse climate effects despite ecological trade-offs, the benefits for diets and nutrition remain unclear. This study quantitatively examines relationships between climate anomalies, forest loss from cropland expansion, and dietary outcomes in Nigeria, Africa's most populous country.
View Article and Find Full Text PDFArch Microbiol
January 2025
Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan, UMS, 88400, Kota Kinabalu, Sabah, Malaysia.
The agricultural productivity and world-wide food security is affected by different phytopathogens, in which Fusarium is more destructive affecting more than 150 crops, now got resistance against many fungicides that possess harmful effects on environment such as soil health, air pollution, and human health. Fusarium fungicide resistance is an increasing concern in agricultural and environmental contexts, requiring a thorough understanding of its causes, implications, and management approaches. The mechanisms of fungicide resistance in Fusarium spp.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
Department of Environmental and Resource Engineering, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark.
U and U are proven to be useful tracers to investigate upper-ocean hydrodynamics due to their source-specific isotopic ratios and conservative behaviors in the open ocean. However, their application in the Pacific Ocean has been limited by scarce observations and unclear source-term information. Here, we present our observations of U and U in the western North Pacific Subtropical Gyre (NPStG), showing the presence of a source of anthropogenic U featured by a low U/U ratio (∼1 × 10), which is an order of magnitude lower than the global fallout signature (∼2 × 10).
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