Browsing by Author "Munishi, Linus K."

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    Characterization of land use influence on soil phosphate bioavailability in Usangu agro-ecosystem-Tanzania
    (ELSEVIER, 2021) Mng’ong’o, Marco; Munishi, Linus K.; Ndakidemi, Patrick A.
    Phosphorus (P) is an important nutrient required for plant growth. Land use influences concentration and bioavail- ability of P in agricultural soils. About 198 soil samples (0-30 cm soil depth) were collected from three land-use types (maize, paddy, and conserved areas) in Usangu basin located in Southern Highland Tanzania. The con- centration of soil P determined were compared among different land-use types and locations. The total P (TP), complexed (Po), and bioavailable P (B-P) were measured. The concentration of TP and B-P was determined by acid digestion and Mehlich 3 method, respectivelly, The Po concentration in soil extract was obtained by subtract- ing B-P from TP. TP, B-P and Po concentration in collected soils samples were in range of; Total P (63.12-1350.9 mg/kg), Bioavailable P (0.52-49.87 mg/kg), and complexed P (62.60-1301.03 mg/kg). The cropping area had high TP but very low B-P, especially in paddy farming areas indicating cropping and associated activity decrease bioavailable P in agricultural soils. Furthermore, soils from cropping areas had higher Al, Fe, and Mg concentra- tions than conserved areas, which caused a substantial reduction in B-P due to increased P fixation and adsorption. It is important to note that converting natural land to farming land could potentially influence soil P dynamics thus affecting P bioavailability, crop productivity, and environmental safety.
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    Towards Agricultural Sustainability: Status and Distribution of Copper in Usangu Agro-Ecosystem, Tanzania
    (ELSEVIER, 2022) Mng’ong’o, Marco; Munishi, Linus K.; Ndakidemi, Patrick A.
    Despite the positive role of copper (Cu) in plants and animals, excessive amounts have environmental and health effects. Cu has been excessively accumulating in agricultural soils worldwide due to increased agrochemicals and wastewater use in farming. The increased Cu concentration in soil negatively impacts soil microbes and plants, affecting crop productivity and environmental quality. Here, the status and spatial distribution of Cu in Tan- zanian agro-ecosystem were characterized as its information are currently missing. The study assessed 198 soil samples from 10 irrigation schemes and 3 land use, where total and bioavailable Cu were determined and contamination status assessed. The variable Cu status and distribution were observed among studied land use where paddy farming areas had higher total (5892.36 μg/kg) and bioavailable Cu (3342 μg/kg) than total and bioavailable Cu concentration in maize farming areas (total Cu 1522.09 μg/kg and bioavailable Cu 779 μg/kg) and conserved areas (total Cu 4415 μg/kg and bioavailable Cu 3267 μg/kg). The bioavailability of Cu for plant uptake was 52% in maize farming areas, 49.9–63.5% in paddy farming areas, and 48.4–51.6% in reserved areas, where farming areas had higher Cu bioavailability. Contrary to other agro-ecosystems worldwide, all Cu concentration values studied in the Usangu agro- ecosystem are within the acceptable limit (100000 μg/kg). However, this should not have to be taken for granted or ignored; there is a need to set strategic management to maintain Cu levels in agro-ecosystem within acceptable limits to ensure environmental quality, food safety, and sustainability.