Abstract
Twenty-two field experiments in England, done between 1986 and 2000, tested the effects of phosphorus (P) fertilizers on number of tubers and tuber yield in Solanum tuberosum . Applying P fertilizer resulted in statistically significant increases in tuber yield in six experiments and the optimal P application rate ranged from c . 90 to 180 kg P/ha. Statistically significant increases in yield in response to application of P fertilizers were found only in soils that contained < 26 mg Olsen-P/l (< Index 3) and appeared to be associated with increases in ground cover. Statistically significant increases in the number of tubers in response to application of P fertilizer were found only in soils that contained < 16 mg Olsen-P/l (< Index 2) and appeared to be associated with an increase in ground cover by the time of tuber initiation ( c. 5–6 week after planting). Each tonne of tuber fresh-weight yield was, on average, associated with removal of 0·39 kg P but regression analysis showed that this value increased as soil Olsen-P increased. Re-analysis of published data showed that whilst the probability of a response to P fertilizer and the optimum P application rate may have been overestimated, some statistically significant responses to P fertilizer did occur when Olsen-P was > 26 mg/l. The absence of yield responses on P Index 3 soils found in the current experiments was attributed to increased use of irrigation that may have increased the availability of soil P. Re-interpretation of data from long-term experiments showed that the agronomic benefits of increasing soil P status by applying more P than is removed by harvested crop parts, are small. Since large P residues, estimated by Olsen-P or degree of soil P saturation, are associated with desorption of P and consequent loss to drainage water it is inadvisable to increase soil P above Index 3. For these reasons, no P fertilizer is recommended for Index 4 soils, an amount equivalent to replacement is recommended for Index 3 soils but up to 110–130 kg P/ha should be applied to Index 0 soils. Applications of foliar P had no effect on number of tubers or tuber yield and this practice cannot be recommended.
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Claims 14
Claim · model-written summary
P fertilizer significantly increased tuber yield in six experiments.
- Taxon
- Solanum tuberosum
Solanum tuberosumt0 - Treatment
- P fertilizere0
- Outcome
- tuber yielde0
- Direction
- increasese0
- Value
- six experimentse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applying P fertilizer resulted in statistically significant increases in tuber yield in six experiments”
t0“Solanum tuberosum”
Claim · model-written summary
The optimal P application rate ranged from about 90 to 180 kg P/ha.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Outcome
- optimal P application ratee0
- Value
- c . 90 to 180 kg P/hae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the optimal P application rate ranged from c . 90 to 180 kg P/ha”
t0“Solanum tuberosum”
Claim · model-written summary
Significant P fertilizer yield increases were found only below 26 mg Olsen-P/l soil.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Treatment
- application of P fertilizerse0
- Outcome
- yielde0
- Direction
- increasese0
- Qualifier
- < 26 mg Olsen-P/l (< Index 3)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Statistically significant increases in yield in response to application of P fertilizers were found only in soils that contained < 26 mg Olsen-P/l (< Index 3)”
t0“Solanum tuberosum”
Claim · model-written summary
Significant tuber number increases were found only below 16 mg Olsen-P/l soil.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Treatment
- application of P fertilizere0
- Outcome
- number of tuberse0
- Direction
- increasese0
- Qualifier
- < 16 mg Olsen-P/l (< Index 2)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Statistically significant increases in the number of tubers in response to application of P fertilizer were found only in soils that contained < 16 mg Olsen-P/l (< Index 2)”
t0“Solanum tuberosum”
Claim · model-written summary
Each tonne of tuber fresh-weight yield was associated on average with removal of 0·39 kg P.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Organ / stage
- tubere0
- Outcome
- removal of 0·39 kg Pe0
- Value
- 0·39 kg Pe0
- Qualifier
- Each tonne of tuber fresh-weight yielde0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Each tonne of tuber fresh-weight yield was, on average, associated with removal of 0·39 kg P”
t0“Solanum tuberosum”
Claim · model-written summary
P removal per tonne increased as soil Olsen-P increased.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Outcome
- this valuee0
- Direction
- increasede0
- Setting
- soil Olsen-Pe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this value increased as soil Olsen-P increased”
t0“Solanum tuberosum”
Claim · model-written summary
Reanalysis found some significant P responses above 26 mg/l Olsen-P.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Treatment
- P fertilizere0
- Outcome
- responsese0
- Qualifier
- Olsen-P was > 26 mg/le0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“some statistically significant responses to P fertilizer did occur when Olsen-P was > 26 mg/l”
t0“Solanum tuberosum”
Claim · model-written summary
Long-term data showed small agronomic benefits from increasing soil P above harvested removal.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Treatment
- applying more P than is removed by harvested crop partse0
- Outcome
- agronomic benefitse0
- Direction
- smalle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the agronomic benefits of increasing soil P status by applying more P than is removed by harvested crop parts, are small”
t0“Solanum tuberosum”
Claim · model-written summary
The authors advise against raising soil P above Index 3.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Outcome
- increase soil P above Index 3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it is inadvisable to increase soil P above Index 3”
t0“Solanum tuberosum”
Claim · model-written summary
No P fertilizer is recommended for Index 4 soils.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Outcome
- no P fertilizer is recommended for Index 4 soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no P fertilizer is recommended for Index 4 soils”
t0“Solanum tuberosum”
Claim · model-written summary
Replacement P is recommended for Index 3 soils.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Outcome
- an amount equivalent to replacement is recommended for Index 3 soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an amount equivalent to replacement is recommended for Index 3 soils”
t0“Solanum tuberosum”
Claim · model-written summary
Up to 110–130 kg P/ha is recommended for Index 0 soils.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Outcome
- up to 110–130 kg P/ha should be applied to Index 0 soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“up to 110–130 kg P/ha should be applied to Index 0 soils”
t0“Solanum tuberosum”
Claim · model-written summary
Foliar P had no effect on tuber number or yield.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Treatment
- Applications of foliar Pe0
- Outcome
- number of tubers or tuber yielde0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applications of foliar P had no effect on number of tubers or tuber yield”
t0“Solanum tuberosum”
Claim · model-written summary
The authors do not recommend foliar P application.
- Taxon
- Solanum tuberosumSolanum tuberosumt0
- Outcome
- this practice cannot be recommendede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this practice cannot be recommended”
t0“Solanum tuberosum”
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See all 450 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.