Potassium chloride and sulphate with 25 kg/ha iron in the main fertilization, or without iron, increased leaf iron

sulfate · nutrient: content · VitisPositive and negative results

2 papers in the same direction as this claim · 1 in the opposite direction

1. no effect
   Trunk injection of magnesium sulphate did not raise grape leaf magnesium concentration.

   A comparison of three methods of magnesium application to grapes. · 2008

   Opposite direction

2. positive
   Additional sulfate improved sulfur availability under drought in grapevine.

   Sulfate enhances metabolic acclimation under drought stress – a comparative study of grapevine and maize · 2025

   Same direction

3. positive
   Iron sulfate spray at 5000 mg/L raised grape leaf iron concentration versus control and other treatments.

   Effects of acidic fertilizers spray on the improvement of iron chlorosis in grape cv. Askari in Yasouj · 2019 · compared with control and other treatments

   Same direction

iron atom · nutrient: content · VitisPositive and negative results

3 papers in the same direction as this claim · 7 in the opposite direction

This claim is about lacking the nutrient, so it counts the other way round here.

1. positive
   Coated Fe EDTA increased iron uptake in leaves and shoots.

   Effect of slow release iron fertilizers on chlorosis in grape · 1992

   Opposite direction

2. positive
   Fe, Zn and B at 200 ppm gave the highest leaf micronutrient content.

   Quality Responses of Table Grapes ‘Flame Seedless’ as Effected by Foliarly Applied Micronutrients · 2021

   Opposite direction

3. positive
   Iron deficiency decreased Fe content in leaves of grape plants grown in an artificial nutrient medium.

   Iron content in grape tissue when supplied with iron‐containing compounds · 1995

   Opposite directionAbout lacking this nutrient, so it counts the other way round

4. positive
   Spraying with 1 g L-1 of chelated iron significantly increased leaf iron to 651.70 mg kg-1 in young grapevines.

   Response of Young grapevines (Kishmishi cultivar) to Spraying by Iron Chelated and the growth regulator benzyl adenine · 2024

   Opposite direction

5. positive
   Foliar iron fertilisation increased iron levels in grapevine leaves and berries.

   Effects of Foliar Fertilizations in the Vitis vinifera L. Species · 2018

   Opposite direction

6. positive
   Iron sulfate spray at 5000 mg/L raised grape leaf iron concentration versus control and other treatments.

   Effects of acidic fertilizers spray on the improvement of iron chlorosis in grape cv. Askari in Yasouj · 2019 · compared with control and other treatments

   Opposite direction

7. positive
   Fe application prevented excessive Mn concentration increases in grapevine leaves and roots under Cu contamination.

   Mycorrhizal inoculation and application of Fe correction in the soil for ameliorating grapevine performance in a copper-contaminated soil · 2021

   Opposite direction

8. negative
   Both Fe deficiency types strongly stimulated root Fe(III)-reductase in Khamri and 140Ru.

   Biochemical Responses to True and Bicarbonate-Induced Iron Deficiency in Grapevine Genotypes · 2006

   Same directionAbout lacking this nutrient, so it counts the other way round

2 papers more in this group

fertilization · nutrient: content · VitisPositive and negative results

42 papers in the same direction as this claim · 4 in the opposite direction

1. positive
   Foliar fertilization increased grapevine leaf iron concentration.

   Vineyard Fertilization Management for Iron Deficiency and Chlorosis Prevention on Carbonate Soil · 2021 · compared with all the observed treatments

   Same directionCites this paper

2. no effect
   Fertilization left fruit juice total nitrogen unchanged in both cultivars.

   Influence of Timing of Nitrogen Fertilizer Application on Grapevines in the San Joaquin Valley · 1991

   Opposite direction

3. no effect
   Soil magnesium fertilizer did not effectively raise grape leaf magnesium concentration.

   A comparison of three methods of magnesium application to grapes. · 2008

   Opposite direction

4. no effect
   Fertilizer applications did not differ significantly in leaf N, P, Mn, and Zn content.

   The Effect of Microbial Fertilizer Applications on Grape Yield, Quality and Mineral Nutrition of Some Early Table Grape Varieties · 2019 · compared with control (no fertilizer)

   Opposite direction

5. no effect
   Summer nitrogen fertigation did not significantly alter vine nitrogen concentration.

   Foliar Urea Application in the Fall Affects Both Nitrogen and Carbon Storage in Young `Concord' Grapevines Grown under a Wide Range of Nitrogen Supply · 2004

   Opposite direction

6. positive
   Phosphorus fertilizer increased leaf phosphorus and magnesium concentrations above critical levels.

   A novel interaction of magnesium translocation with the supply of phosphorus to roots of grapevine (Vitis viniferaL.)^* · 1990

   Same direction

7. positive
   Applied manure increased grape petiole nitrate nitrogen, phosphorus and potassium contents over the control.

   Application of Poultry Manure Influences Thompson Seedless Grape Production and Soil Properties · 1988 · compared with the control

   Same direction

8. positive
   Coated Fe EDTA increased iron uptake in leaves and shoots.

   Effect of slow release iron fertilizers on chlorosis in grape · 1992

   Same direction

38 papers more in this group