Abstract
Introduction A proper understanding of the residual value of zinc (Zn) is essential for sustainable biofortification of food crops. This study hypothesized that Zn applied at rates higher than the current national recommendation would have significant residual benefits on maize productivity and Zn uptake. Methods The residual effects of soil-applied Zn on maize grain Zn concentration and uptake were evaluated at two Malawian agricultural research stations, Chitedze and Chitala, each with Lixisols and Vertisols soil types. The experiment used three Zn fertilizer rates (1, 30, and 90 kg Zn ha -1 ) applied as ZnSO 4 .7H 2 O in the previous season, arranged in a randomized complete block design (RCBD) with 10 replications per site. Maize grain yield, and Zn concentrations in grain and stover were measured at harvest. Data were analyzed to assess crop yield and Zn uptake relative to Zn application rates and soil types. Results Maize grain yield in the second season was 24.6% higher on plots receiving 30 kg Zn ha -1 compared to those with 1 kg Zn ha -1 . Grain Zn concentration and Zn uptake increased by 12.5% and 29.6%, respectively, on plots with 30 kg Zn ha -1 versus the lowest rate. Application of 90 kg Zn ha -1 did not provide additional benefits over 30 kg ha -1 for yield, Zn concentration, or Zn uptake. Residual Zn benefits did not vary between soil types. Discussion These results demonstrate that residual application of 30 kg Zn ha -1 significantly enhances maize productivity and Zn biofortification compared to the current national recommendation of 1 kg Zn ha -1 . Given no added advantage with 90 kg Zn ha -1 , revising Zn fertilizer guidelines to higher but optimized rates could improve the effectiveness of biofortification programs without environmental or economic drawbacks.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 6
Claim · model-written summary
Residual 30 kg Zn ha -1 increased second season maize grain yield by 24.6% versus 1 kg Zn ha -1.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Maize grain yield in the second season was 24.6% higher on plots receiving 30 kg Zn ha -1 compared to those with 1 kg Zn ha -1 .”
Claim · model-written summary
Residual 30 kg Zn ha -1 increased grain zinc concentration by 12.5% versus the lowest rate.
- Treatment
- 30 kg Zn ha -1e0
- Outcome
- Grain Zn concentratione0
- Direction
- increasede0
- Value
- 12.5%e0
- Comparator
- lowest ratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Grain Zn concentration and Zn uptake increased by 12.5% and 29.6%, respectively, on plots with 30 kg Zn ha -1 versus the lowest rate.”
t0“maize”
Claim · model-written summary
Residual 30 kg Zn ha -1 increased Zn uptake by 29.6% versus the lowest rate.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Grain Zn concentration and Zn uptake increased by 12.5% and 29.6%, respectively, on plots with 30 kg Zn ha -1 versus the lowest rate.”
t0“maize”
Claim · model-written summary
Residual 90 kg Zn ha -1 gave no extra benefit over 30 kg ha -1 for yield, zinc concentration or zinc uptake.
- Treatment
- 90 kg Zn ha -1e0
- Outcome
- yield, Zn concentration, or Zn uptakee0
- Direction
- did not provide additional benefitse0
- Comparator
- 30 kg ha -1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Application of 90 kg Zn ha -1 did not provide additional benefits over 30 kg ha -1 for yield, Zn concentration, or Zn uptake.”
t0“maize”
Claim · model-written summary
Residual zinc benefits did not vary between soil types.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Residual Zn benefits did not vary between soil types.”
t0“maize”
Claim · model-written summary
The authors suggest revising zinc fertilizer guidelines to higher optimized rates.
- Outcome
- revising Zn fertilizer guidelines to higher but optimized ratese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“revising Zn fertilizer guidelines to higher but optimized rates could improve the effectiveness of biofortification programs”
t0“maize”
The same questions in other papers
zinc atom · nutrient: content · Zea mays (maize)Results differ
198 papers in the same direction as this paper · 33 in the opposite direction · 3 reporting no difference from an alternative
- positive
- positive
- no effect
231 papers more in this group
See all 235 papers →zinc atom · yield · Zea mays (maize)Results differ
390 papers in the same direction as this paper · 47 in the opposite direction · 3 reporting no difference from an alternative
- no effect
- positive
- positive
437 papers more in this group
See all 441 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.