Abstract
Abstract Phosphite (Phi) may potentially supply phosphorus (P) nutrition to plants and is widely marketed as a super P fertilizer for many crops. This study investigated the effects of Phi on growth and P nutrition in spinach (Spinacia oleracea L.). High-rate foliar application experiments designed to evaluate the phytotoxicity and P nutritional potential of different Phi formulations by foliar application at two rates (0.15 and 0.3% P2O5) showed that all Phi formulations did not improve plant growth under different available P-soils, but rather significantly decreased shoot dry weight (DW) at the higher rate. In two other soil and hydroponic experiments, Phi was foliar applied at a low rate (0.05% P2O5) and root P treatments were combinations of Phi and phosphate (Pi) at different Pi : Phi ratios for a high P level (the soil experiment) or a low P level (the hydroponic experiment). In both experiments, shoot DW decreased markedly as the Pi : Phi ratios decreased from 100:0 to 0:100 and Phi foliar application did not improve plant growth. In the soil experiment, plants grew poorest at 0:100, but grew well when both Phi and Pi were applied at a high rate of 115 mg P pot−1, indicating that at this level Phi had a negative effect on only severely P-deficient plants. Root growth of no Pi-fertilized plants was strongly inhibited by Phi from either root or foliar application. In both experiments, P concentration drastically decreased with decreasing Pi : Phi ratios from 100:0 to 0:100, but increased substantially with foliar application of Phi compared with Pi, suggesting that Phi was absorbed poorly by the roots, but was well absorbed by the leaves compared to Pi. We conclude that Phi cannot be used as a P fertilizer for spinach via either root or foliar applications at low or high levels, and also that Phi has no beneficial effect on the growth of spinach. As Phi is now widely marketed as a P fertilizer for many crops, care should be taken in selecting Phi as a P fertilizer for a given crop.
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Claims 14
Claim · model-written summary
No phosphite formulation improved spinach growth under soils differing in available P.
- Taxon
- spinach
Spinacia oleraceat0 - Treatment
- Phi formulationse0
- Outcome
- plant growthe0
- Direction
- did not improvee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“all Phi formulations did not improve plant growth under different available P-soils”
Claim · model-written summary
At the higher foliar rate, phosphite formulations significantly decreased spinach shoot dry weight.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- Phi formulationse0
- Outcome
- shoot dry weight (DW)e0
- Direction
- decreasede0
- Qualifier
- at the higher ratee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“all Phi formulations did not improve plant growth under different available P-soils, but rather significantly decreased shoot dry weight (DW) at the higher rate”
Claim · model-written summary
Spinach shoot DW decreased markedly as the Pi : Phi ratio decreased from 100:0 to 0:100 in the soil and hydroponic experiments.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- Pi : Phi ratiose0
- Outcome
- shoot DWe0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“shoot DW decreased markedly as the Pi : Phi ratios decreased from 100:0 to 0:100”
Claim · model-written summary
Low-rate foliar phosphite application did not improve spinach growth.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- Phi foliar applicatione0
- Outcome
- plant growthe0
- Direction
- did not improvee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“Phi foliar application did not improve plant growth”
Claim · model-written summary
In the soil experiment, spinach plants grew poorest at the 0:100 Pi : Phi ratio.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- 0:100e0
- Outcome
- plants grew pooreste0
- Direction
- pooreste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“plants grew poorest at 0:100”
Claim · model-written summary
In the soil experiment, spinach grew well when both Phi and Pi were applied at a high rate of 115 mg P pot−1.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- both Phi and Pi were applied at a high rate of 115 mg P pot−1e0
- Outcome
- grew welle0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“grew well when both Phi and Pi were applied at a high rate of 115 mg P pot−1”
Claim · model-written summary
The authors interpret that at 115 mg P pot−1 phosphite had a negative effect only on severely P-deficient spinach plants.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- negative effecte0
- Qualifier
- only severely P-deficient plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“indicating that at this level Phi had a negative effect on only severely P-deficient plants”
Claim · model-written summary
Root growth of spinach not fertilized with Pi was strongly inhibited by phosphite from either root or foliar application.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- Phi from either root or foliar applicatione0
- Outcome
- Root growthe0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“Root growth of no Pi-fertilized plants was strongly inhibited by Phi from either root or foliar application”
Claim · model-written summary
Spinach P concentration decreased drastically as the Pi : Phi ratio decreased from 100:0 to 0:100.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- Pi : Phi ratiose0
- Outcome
- P concentratione0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“P concentration drastically decreased with decreasing Pi : Phi ratios from 100:0 to 0:100”
Claim · model-written summary
Spinach P concentration increased substantially with foliar application of Phi compared with Pi.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- foliar application of Phie0
- Outcome
- P concentratione0
- Direction
- increasede0
- Comparator
- Pie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“P concentration drastically decreased with decreasing Pi : Phi ratios from 100:0 to 0:100, but increased substantially with foliar application of Phi compared with Pi”
Claim · model-written summary
The authors suggest phosphite was absorbed poorly by roots but well by leaves compared with phosphate.
- Taxon
- spinachSpinacia oleraceat0
- Organ / stage
- rootse0
- Compound
- Phie0
- Outcome
- absorbed poorly by the rootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“suggesting that Phi was absorbed poorly by the roots, but was well absorbed by the leaves compared to Pi”
Claim · model-written summary
The authors conclude that Phi cannot be used as a P fertilizer for spinach via root or foliar applications at low or high levels.
- Taxon
- spinachSpinacia oleraceae0
- Outcome
- cannot be used as a P fertilizere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phi cannot be used as a P fertilizer for spinach via either root or foliar applications at low or high levels”
Claim · model-written summary
The authors conclude that phosphite has no beneficial effect on spinach growth.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- Phie0
- Outcome
- growthe0
- Direction
- no beneficial effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phi has no beneficial effect on the growth of spinach”
Claim · model-written summary
The authors advise care in selecting Phi as a P fertilizer for a given crop.
- Outcome
- care should be taken in selecting Phi as a P fertilizere0
Not reportedTaxon
Verbatim
e0“care should be taken in selecting Phi as a P fertilizer for a given crop”
The same questions in other papers
application · nutrient: content · Spinacia oleracea (spinach)Positive and negative results
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See all 25 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.