Selenium biofortification of crops on a Malawi Alfisol under conservation agriculture

Ligowe, Ivy Sichinga; Young, Scott D.; Ander, E. Louise; Kabambe, V. H.; Chilimba, A. D.; Bailey, Elizabeth H.; Lark, R. Murray; Nalivata, Patson C.

doi:10.1016/j.geoderma.2020.114315

Cited by 23 publications

(20 citation statements)

References 37 publications

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“…Keskinen et al, (2009) studied the fate of residual Se in Finland soils, amended with Se fertilizers and observed that soluble Se account for approximately 1% of Se T . Similarly, Ligowe et al, (2020) investigated the fate of residual isotopically labelled 77 Se fertilizer in Malawian soils, using the same sequential extraction procedure as used in the current study and found that the soluble fraction of Se accounted for * 3% of total 77 Se applied in the preceding year.…”

Section: Fractionation Of Soil Seleniummentioning

confidence: 81%

Multiple geochemical factors may cause iodine and selenium deficiency in Gilgit-Baltistan, Pakistan

Shariati

Bailey

Arshad

et al. 2021

Environ Geochem Health

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Deficiencies of the micronutrients iodine and selenium are particularly prevalent where populations consume local agricultural produce grown on soils with low iodine and selenium availability. This study focussed on such an area, Gilgit-Baltistan in Pakistan, through a geochemical survey of iodine and selenium fractionation and speciation in irrigation water and arable soil. Iodine and selenium concentrations in water ranged from 0.01–1.79 µg L−1 to 0.016–2.09 µg L−1, respectively, which are smaller than levels reported in similar mountainous areas in other parts of the world. Iodate and selenate were the dominant inorganic species in all water samples. Average concentrations of iodine and selenium in soil were 685 µg kg−1 and 209 µg kg−1, respectively, much lower than global averages of 2600 and 400 µg kg−1, respectively. The ‘reactive’ fractions (‘soluble’ and ‘adsorbed’) of iodine and selenium accounted for < 7% and < 5% of their total concentrations in soil. More than 90% of reactive iodine was organic; iodide was the main inorganic species. By contrast, 66.9 and 39.7% of ‘soluble’ and ‘adsorbed’ selenium, respectively, were present as organic species; inorganic selenium was mainly selenite. Very low distribution coefficients (kd = adsorbed/soluble; L kg−1) for iodine (1.07) and selenium (1.27) suggested minimal buffering of available iodine and selenium against leaching losses and plant uptake. These geochemical characteristics suggest low availability of iodine and selenium in Gilgit-Baltistan, which may be reflected in locally grown crops. However, further investigation is required to ascertain the status of iodine and selenium in the Gilgit-Baltistan food supply and population.

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Section: Fractionation Of Soil Seleniummentioning

confidence: 81%

Multiple geochemical factors may cause iodine and selenium deficiency in Gilgit-Baltistan, Pakistan

Shariati

Bailey

Arshad

et al. 2021

Environ Geochem Health

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“…After wheat harvest, a maize crop was planted on the site (June 2018), grown, and subsequently sampled (November 2018); a second wheat crop was then planted (December 2018) and harvested (June 2019) as before. Soil was sampled at each harvest and analysed for soluble (Se sol ), adsorbed (Se ads ), organic (Se TMAH ), and total 77 Se ( 77 Se T ); plant analysis included grain and other parts (Mathers et al 2017 ; Ligowe et al 2020b ).…”

Section: Methodsmentioning

confidence: 99%

“…The milled soil was also used for measuring soil organic carbon in a Leco TruMac CN analyser (Stockport, UK). Acid digestion (HNO 3 –HClO 4 –HF) of finely ground soil was undertaken in PFA vessels using a teflon-coated graphite block digester (Model A3, Analysco Ltd.) controlled by a Eurotherm unit (Mather et al 2017 ; Ligowe et al 2020b ). Total selenium concentration (Se T ), 77 Se isotopes, and other elemental analyses were undertaken using a triple-quadrupole ICP-MS (model iCAP-TQ, Thermo Scientific, Bremen, Germany).…”

Section: Methodsmentioning

confidence: 99%

“…Inorganic Se species, selenite (Se IV ) and selenate (Se VI ), are both available for plant uptake (Broadley et al 2006 ; Li et al 2008 ). Selenate is normally used for biofortification because it is more soluble and hence more bioavailable (Chilimba et al 2012a ; Ligowe et al 2020b ), but it is also more prone to leaching, particularly in coarse-textured soils at high pH. It is recognised that soils in Gilgit-Baltistan are largely coarse-textured and calcareous with a high pH (> 7) (Hashmi and Shafiullah 2003 ).…”

Section: Introductionmentioning

confidence: 99%

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Fate of selenium in biofortification of wheat on calcareous soil: an isotopic study

Shariati

Bailey

Arshad

et al. 2021

Environ Geochem Health

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Selenium (Se) biofortification of staple cereal crops can improve the Se nutritional status of populations. A field trial employing an enriched stable isotope of Se (77Se) was undertaken over three consecutive cropping seasons in a coarse-textured, calcareous soil in Gilgit-Baltistan, Pakistan. The objectives were to (1) assess the feasibility and efficiency of Se biofortification, (2) determine the fate of residual Se, and (3) assess the consequences for dietary Se intake. Isotopically enriched 77Se (77SeFert) was applied, either as selenate or as selenite, at three levels (0, 10, and 20 g ha−1) to a wheat crop. Residual 77SeFert availability was assessed in subsequent crops of maize and wheat without further 77SeFert addition. Loss of 77SeFert was c.35% by the first (wheat) harvest, for both selenium species, attributable to the practice of flood irrigation and low adsorption capacity of the soil. No 77SeFert was detectable in subsequent maize or wheat crops. The remaining 77SeFert in soil was almost entirely organically bound and diminished with time following a reversible (pseudo-)first-order trend. Thus, repeat applications of Se would be required to adequately biofortify grain each year. In contrast to native soil Se, there was no transfer of 77SeFert to a recalcitrant form. Grain from control plots would provide only 0.5 µg person−1 day−1 of Se. By contrast, a single application of 20 g ha−1 SeVI could provide c. 47 µg person−1 day−1 Se in wheat, sufficient to avoid deficiency when combined with dietary Se intake from other sources (c. 25 µg day−1).

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“…For land used for growing crops, amendments such as lime, fertilisers, manure or incorporation of crop residues are often used for moisture retention or to improve the availability of essential elements (e.g. Zn, Se) for crop health and for the consumer (Vondr a ckov a et al, 2017;Ligowe et al, 2020;Manzeke Muneta et al, 2020). In Zambia's farming systems, lime and manure are recommended amendments for improving soil acidity and fertility, but usually only small doses are applied by most farmers due to cost constraints.…”

Section: Introductionmentioning

confidence: 99%

Do soil amendments used to improve agricultural productivity have consequences for soils contaminated with heavy metals?

Kaninga

Chishala

Maseka

et al. 2020

Heliyon

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This study presents an analysis of the effects of manure and lime commonly used to improve agricultural productivity and evaluates the potential for such soil amendments to mobilise/immobilise metal fractions in soils contaminated from nearby mine tailings in the Zambian Copperbelt. Lime and manure were applied at the onset of the study, and their effects were studied over two planting seasons, i.e. 2016-17 and 2017-18. Operationally defined plant-available Cd, Cu, Ni, Pb and Zn in the soil, were determined by extraction with DTPA-TEA (diethylenetriaminepentaacetic acid-triethanolamine) and 0.01 M Ca(NO 3 ) 2 , before, and after, applying the amendments. In unamended soils, Cd was the most available and Ni the least. Lime application decreased extractable Cd, Cu, Ni, Pb and Zn. The response to lime was greater in soils with an initially acidic pH than in those with approximately neutral pH values. Manure increased DTPA extractable Zn, but decreased DTPA and Ca(NO 3 ) 2 extractable Cd, Cu and Pb. Combined lime and manure amendment exhibited a greater reduction in DTPA extractable Cd, Ni, Pb, Zn, as well as for Ca(NO 3 ) 2 extractable Cd compared to separate applications of lime and manure. The amendments had a significant residual effect on most of the soil fractions between season 1 and 2. The results obtained in this study showed that soil amendment with minimal lime and manure whilst benefiting agricultural productivity, may significantly reduce the mobility or plant availability of metals from contaminated agricultural soils. This is important in contaminated, typical tropical soils used for crop production by resource poor communities affected by mining or other industrial activities.

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Selenium biofortification of crops on a Malawi Alfisol under conservation agriculture

Cited by 23 publications

References 37 publications

Multiple geochemical factors may cause iodine and selenium deficiency in Gilgit-Baltistan, Pakistan

Multiple geochemical factors may cause iodine and selenium deficiency in Gilgit-Baltistan, Pakistan

Fate of selenium in biofortification of wheat on calcareous soil: an isotopic study

Do soil amendments used to improve agricultural productivity have consequences for soils contaminated with heavy metals?

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