Abstract
Abstract Aims Fertilisating crops with zinc (Zn) is considered important to enhance agricultural productivity and combat human Zn deficiencies in sub-Saharan Africa. However, it is unclear on which soils Zn fertilisation can lead to higher yields and increased grain Zn concentrations. This study aimed to find soil properties that predict where soil Zn is limiting maize yields and grain Zn concentrations, and where these respond positively to Zn fertilisation. Methods Zinc omission trials were set up at multiple farm locations in Kenya (n = 5), Zambia (n = 4) and Zimbabwe (n = 10). Grain yields and tissue Zn concentrations were analysed from plots with a full fertiliser treatment as compared to plots where Zn was omitted. Results A positive maize yield response to soil Zn fertilisation was found at only two out of nineteen locations, despite soil Zn levels being below suggested critical concentrations at most locations. Soil properties nor plant concentrations were able to explain maize yield response to Zn fertilisation. However, positive responses in Zn uptake and grain Zn concentrations to Zn fertilisation were found at the majority of sites, especially in soils with low pH and organic carbon contents. Labile soil Zn measurements related more with Zn uptake (R 2 = 0.35) and grain Zn concentrations (R 2 = 0.26) than actual available Zn measurements. Conclusions We conclude that soil Zn fertilisation did not increase maize yields, but can increase maize grain Zn concentrations, especially in soils with low pH and organic carbon content. Predicting a yield response to Zn fertilisation based on soil properties remains a challenge.
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Claims 7
Claim · model-written summary
Soil zinc fertilisation increased maize yield at only two of nineteen locations.
- Treatment
- soil Zn fertilisatione0
- Outcome
- maize yielde0
- Direction
- positivee0
- Value
- two out of nineteen locationse0
- Comparator
- Zn was omittede1
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A positive maize yield response to soil Zn fertilisation was found at only two out of nineteen locations”
e1“plots where Zn was omitted”
Claim · model-written summary
Most sites had soil zinc below suggested critical concentrations despite limited yield response.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soil Zn levels being below suggested critical concentrations at most locations”
t0“maize yields”
Claim · model-written summary
Soil properties and plant concentrations did not explain maize yield response to zinc fertilisation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Soil properties nor plant concentrations were able to explain maize yield response to Zn fertilisation”
Claim · model-written summary
Zinc fertilisation increased zinc uptake at the majority of sites, especially soils with low pH and organic carbon.
- Treatment
- Zn fertilisatione0
- Outcome
- Zn uptakee0
- Direction
- positivee0
- Qualifier
- soils with low pH and organic carbon contentse0
- Comparator
- Zn was omittede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“positive responses in Zn uptake and grain Zn concentrations to Zn fertilisation were found at the majority of sites, especially in soils with low pH and organic carbon contents”
t0“maize yields”
e1“plots where Zn was omitted”
Claim · model-written summary
Zinc fertilisation increased grain zinc concentration at the majority of sites, especially soils with low pH and organic carbon.
- Treatment
- Zn fertilisatione0
- Outcome
- grain Zn concentrationse0
- Direction
- positivee0
- Qualifier
- soils with low pH and organic carbon contentse0
- Comparator
- Zn was omittede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“positive responses in Zn uptake and grain Zn concentrations to Zn fertilisation were found at the majority of sites, especially in soils with low pH and organic carbon contents”
t0“maize yields”
e1“plots where Zn was omitted”
Claim · model-written summary
Labile soil zinc measurements related more strongly to zinc uptake than actual available zinc measurements.
- Outcome
- Zn uptakee0
- Direction
- related moree0
- Value
- R 2 = 0.35e0
- Comparator
- actual available Zn measurementse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Labile soil Zn measurements related more with Zn uptake (R 2 = 0.35) and grain Zn concentrations (R 2 = 0.26) than actual available Zn measurements”
t0“maize yields”
Claim · model-written summary
Labile soil zinc measurements related more strongly to grain zinc concentration than actual available zinc measurements.
- Outcome
- grain Zn concentrationse0
- Direction
- related moree0
- Value
- R 2 = 0.26e0
- Comparator
- actual available Zn measurementse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Labile soil Zn measurements related more with Zn uptake (R 2 = 0.35) and grain Zn concentrations (R 2 = 0.26) than actual available Zn measurements”
t0“maize yields”
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