HA+Fe was the best treatment for overall growth, yield and edible-part Fe accumulation in lettuce.

iron atom · yield · Lactuca sativa (garden lettuce)Results differ

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

1. negative
   Fe, Zn and Mn deficiency led to a lesser production of dry mass in lettuce.

   Effect of iron, zinc and manganese shortage-induced change on photosynthetic pigments, some osmoregulators and chlorophyll fluorescence parameters in lettuce · 2017

   Opposite direction

2. negative
   Iron at 2.0 mM reduced lettuce yield 25.3% versus control.

   Iron Biofortification of Red and Green Pigmented Lettuce in Closed Soilless Cultivation Impacts Crop Performance and Modulates Mineral and Bioactive Composition · 2019 · compared with control treatment

   Opposite direction

3. positive
   The Fe chelates also increased lettuce yields.

   Effects of Fe compounds on nutrient uptake by plants grown in sand media with different pH · 2004

   Same direction

other · yield · Lactuca sativa (garden lettuce)Positive and negative results

32 papers in the same direction as this claim · 2 in the opposite direction · 1 reporting no difference from an alternative

1. no effect
   Fine particle amendments had little effect on field lettuce yield.

   Effects of textural amendment of coarse soils on crop growth and water use · 1980 · compared with unamended soil

   Opposite direction

2. no effect
   Silicon amendment insignificantly increased the output of flowering Chinese cabbage and lettuce grown in Cd over-standard soils.

   Effect of Application of Silicon Amendment on Cd Over-Standard Soils of Vegetable Fields · 2012 · compared with control

   Opposite direction

3. no effect
   Organic substrate amendments gave lettuce yields similar to mineral fertilizer.

   Effects of spent mushroom substrates and inorganic fertilizer on the characteristics of a calcareous clayey‐loam soil and lettuce production · 2016 · compared with mineral fertilizer

   No difference from an alternative

4. positive
   Trichoderma biostimulants, especially GV41, increased lettuce yield in unfertilized plots.

   Trichoderma-Based Biostimulants Modulate Rhizosphere Microbial Populations and Improve N Uptake Efficiency, Yield, and Nutritional Quality of Leafy Vegetables · 2018 · compared with unfertilized plots

   Same direction

5. positive
   Compost improved plant growth and yield.

   The Effects of Biochar and Its Combination with Compost on Lettuce (Lactuca sativaL.) Growth, Soil Properties, and Soil Microbial Activity and Abundance · 2017

   Same direction

6. positive
   Under non-fertilized regimens, foliar plant biostimulants increased growth and yield of baby lettuce compared with non-treated plants.

   Effect of Vegetal- and Seaweed Extract-Based Biostimulants on Agronomical and Leaf Quality Traits of Plastic Tunnel-Grown Baby Lettuce under Four Regimes of Nitrogen Fertilization · 2019 · compared with non-treated plants

   Same direction

7. positive
   TG41 plus VBP increased fresh lettuce yield by 67% under 0N fertilization.

   Appraisal of Combined Applications of Trichoderma virens and a Biopolymer-Based Biostimulant on Lettuce Agronomical, Physiological, and Qualitative Properties under Variable N Regimes · 2020 · compared with 0N fertilization

   Same direction

8. positive
   Wheat mash amendment increased lettuce head weight in unfumigated soil.

   Efficacy of Bacillus thuringiensis, Paecilomyces marquandii,and Streptomyces costaricanus with and without Organic Amendments against Meloidogyne hapla Infecting Lettuce. · 2000

   Same direction

27 papers more in this group