Oxalic acid with rock phosphate gave the highest growth increase.

oxalic acid · growth · Zea mays (maize)Positive and negative results

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

1. negative
   Oxalic acid gave the minimum maize shoot dry weight, 4.06 g pot−1.

   Comparison of Low-Molecular-Weight Organic Acids and Ethylenediaminetetraacetic Acid to Enhance Phytoextraction of Heavy Metals by Maize · 2013

   Opposite direction

2. positive
   At the lowest Pb level, oxalic acid increased maize shoot dry weight against no organic acid.

   Lead Phytostabilization and Cationic Micronutrient Uptake by Maize as Influenced by Pb Levels and Application of Low Molecular Weight Organic Acids · 2019 · compared with absence of organic acid

   Same direction

3. positive
   5 mmol kg−1 oxalic acid increased Z. mays total biomass 2.97 folds.

   Response of growth and Pb accumulation characteristics of plants with intercropping Arabis alpina - Zea mays to exogenous oxalic acid · 2023

   Same direction

4. positive
   Oxalic acid increased root biomass.

   Effects of Natural Organic Acids on Growth of Maize and Uptake of Copper and Lead by Maize in Contaminated Soil · 2011

   Same direction

phosphorus · growth · Zea mays (maize)Positive and negative results

251 papers in the same direction as this claim · 51 in the opposite direction · 3 reporting no difference from an alternative

1. positive
   Single super phosphate gave a higher total biomass than phosphate rocks in maize and cowpea.

   Effects of phosphate rock application on dry matter yield and phosphorus recovery of maize and cowpea grown in sequence · 2010 · compared with phosphate rocks (PR)

   Same directionCited by this paper

2. negative
   Growth was diminished under drought with prohexadione-Ca treatment alone.

   Participation of abscisic acid and gibberellins produced by endophyticAzospirillumin the alleviation of drought effects in maize · 2009

   Opposite direction

3. no effect
   Supplemental N and P did not alleviate crop growth inhibition.

   Allelopathic Effects of Annual Weed Residues on Growth and Nutrient Uptake of Corn and Soybeans¹ · 1984

   Opposite direction

4. no effect
   Emergence m-2 was not significantly affected by nitrogen and phosphorus levels.

   Effect of Different Levels of Nitrogen and Phosphorus on the Phenology and Yield of Maize Varieties · 2014

   Opposite direction

5. negative
   Phosphorus deprivation rapidly and strongly reduced leaf expansion.

   Maize root system growth and development as influenced by phosphorus deficiency · 1999 · compared with P deprivation

   Opposite direction

6. negative
   Phosphorus deprivation decreased maize shoot fresh weight.

   Phosphate Deficiency in Maize. V. Mobilization of Nitrogen and Phosphorus within Shoots of Young Plants and its Relationship to Senescence · 1995

   Opposite direction

7. no effect
   Phosphorus and zinc foliar spray had no effect on dry matter yield of forage maize.

   The effects of a foliar spray containing phosphorus and zinc on the development, composition and yield of forage maize · 2001

   Opposite direction

8. negative
   Under severe dehydration, pressurization induced only brief elongation and slight growth-induced water-potential response.

   Root pressurization affects growth-induced water potentials and growth in dehydrated maize leaves · 2003

   Opposite direction

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