Mapping the Spatial Variability of Soil Acidity in Zambia

Chabala, Lydia M.; Mulolwa, Augustine; Lungu, Obed I.

doi:10.3390/agronomy4040452

Cited by 16 publications

(8 citation statements)

References 9 publications

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“…TMP had a detection frequency of 34.6 % and was detected at relatively lower concentration (maximum of 140 ng/L) as compared with SMX. This could be partly due to its high distribution coefficient (K d ), and that the soil pH ranges in the study area of 4.02-5.56 (Chabala et al, 2014) are within TMP optimum sorption pH (4-6); hence, TMP is expected to be largely immobile (Kodešová et al, 2015). In addition, TMP is almost exclusively administered together with sulfonamides such as SMX in fixed ratio (1:5, TMP: SMX), leading to its lower mass load into the environment (WHO, 2016a).…”

Section: Resultsmentioning

confidence: 95%

Occurrence of antibiotics and antiretroviral drugs in source-separated urine, groundwater, surface water and wastewater in the peri-urban area of Chunga in Lusaka, Zambia

Ngumba

Gachanja

Nyirenda

et al. 2020

WSA

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Recently, there has been an increased interest in bridging the knowledge gap in the occurrence and fate of pharmaceuticals in African urban water cycles. In this study, the occurrence of 7 antibiotics and 3 antiretrovirals in source-separated urine, groundwater, wastewater and surface water of the peri-urban area of Chunga in Lusaka, Zambia, was studied. In groundwater, the pharmaceuticals were only sporadically present with 4 antibiotics and 1 antiretroviral detected. The concentration of the antibiotics ranged from below limit of quantification (<LOQ) to 880 ng/L, with sulfamethoxazole having the highest detection frequency of 42.3%. In the surface water, a comparatively high concentration of pharmaceuticals was measured with concentrations ranging from <LOQ–11 800 ng/L to <LOQ–49 700 ng/L for antibiotics and antiretroviral drugs, respectively. Similarly, the concentration of antibiotics in wastewater treatment plant (WWTP) influent and effluent waters ranged from 100–33 300 ng/L and 80–30 040 ng/L, respectively. The concentration of the antiretrovirals was also relatively high in the wastewater and ranged from 680–118 970 ng/L and 1 720–55 760 ng/L in the influent and effluent, respectively. The concentration of the target analytes in source-separated urine were several orders of magnitude higher than in wastewater. Sulfamethoxazole, trimethoprim and lamivudine had the highest concentrations, of 7 740 µg/L, 12 800 µg/L and 10 010 µg/L, respectively. The high concentration detected in source-separated urine calls for precautionary measures to be undertaken when such urine is to be used as a fertilizer. However, urine source separation has a major advantage of pooling a significant proportion of excreted pharmaceuticals into small manageable volumes which can be effectively treated, minimizing environmental contamination. The high concentrations of antibiotics and antiretroviral drugs measured in this study necessitate creation of effective barriers to mitigate the possible environmental and human health risks.

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Section: Resultsmentioning

confidence: 95%

Occurrence of antibiotics and antiretroviral drugs in source-separated urine, groundwater, surface water and wastewater in the peri-urban area of Chunga in Lusaka, Zambia

Ngumba

Gachanja

Nyirenda

et al. 2020

WSA

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“…This method is based on the creation of a semivariogram graphic and from the information contained in the best-fitted model [28,29].…”

Section: Interpolation Methodsmentioning

confidence: 99%

Tools for Optimizing Management of a Spatially Variable Organic Field

Panagopoulos

Jesús

Ben‐Asher³

2015

Agronomy

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Geostatistical tools were used to estimate spatial relations between wheat yield and soil parameters under organic farming field conditions. Thematic maps of each factor were created as raster images in R software using kriging. The Geographic Resources Analysis Support System (GRASS) calculated the principal component analysis raster images for soil parameters and yield. The correlation between the raster arising from the PC1 of soil and yield parameters showed high linear correlation (r = 0.75) and explained 48.50% of the data variance. The data show that durum wheat yield is strongly affected by soil parameter variability, and thus, the average production can be substantially lower than its potential. Soil water content was the limiting factor to grain yield and not nitrate as in other similar studies. The use of precision agriculture tools helped reduce the level of complexity between the measured parameters by the grouping of several parameters and demonstrating that precision agriculture tools can be applied in small organic fields, reducing costs and increasing wheat yield. Consequently, site-specific applications could be expected to improve the yield without increasing excessively the cost for farmers and enhance environmental and economic benefits. OPEN ACCESSAgronomy 2015, 5 90

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“…Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License retention. In addition, pests, disease, poor agronomic practices such as late planting, weeding, and planting uncertified poor quality seeds also reduce crop yields (Chabala et al, 2014: Tunwari et al, 2018. Traditionally, it is a rain-fed crop, with most groundnut farmers being small-holder; they have limited resources to and seldom use inputs (fertilisers, pesticides, lime, and supplemental irrigation systems) to address these production constraints (Mukuka and Shipekesa, 2013).…”

Section: Introductionmentioning

confidence: 99%

Effects of biochar and gypsum soil amendments on groundnut (Arachis hypogaea L.) dry matter yield and selected soil properties under water stress

Ngulube¹,

Mweetwa²,

Phiri³

et al. 2018

Afr. J. Agric. Res.

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The effects of amending soil with gypsum and biochar on groundnut chlorophyll concentration, water use efficiency (WUE), biomass yield and selected soil properties were investigated under water stress. Gypsum (CaSO 4 .2H 2 O) was applied at 0 and 200 kg/ha, groundnut shell biochar at 1, 2 and 4% w/w of soil, and water at 100, 70 and 40% of daily plant water requirement (PWR) as main, sub and sub-sub plots, respectively, in a split-split-plot design. Biochar neutralized the acid soil, significantly raising soil pH from 5 to 7.15 and increasing cation exchange capacity by 75%. Biochar amended at 1 and 2%, increased groundnut dry matter yield by 28%. The optimum biochar application rate for dry matter yield was 1.4% w/w. Biochar application at 4% and irrigation at 40% of PWR reduced the WUE by 45 and 50%, respectively. Chlorophyll concentration index was highest at 40% of PWR. The results suggest that biochar has potential to raise soil pH, increase moisture retention and improve crop performance. Applying water at 100% PWR can increase groundnut dry matter yields, while higher gypsum application rates may be required to affect crop performance.

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Mapping the Spatial Variability of Soil Acidity in Zambia

Cited by 16 publications

References 9 publications

Occurrence of antibiotics and antiretroviral drugs in source-separated urine, groundwater, surface water and wastewater in the peri-urban area of Chunga in Lusaka, Zambia

Occurrence of antibiotics and antiretroviral drugs in source-separated urine, groundwater, surface water and wastewater in the peri-urban area of Chunga in Lusaka, Zambia

Tools for Optimizing Management of a Spatially Variable Organic Field

Effects of biochar and gypsum soil amendments on groundnut (Arachis hypogaea L.) dry matter yield and selected soil properties under water stress

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