Abstract
Crop responses to increasing P fertilization are often variable and poorly related to soil P test. Our objectives were to determine the influence of P fertilizer on the growth and seed yield of canola ( Brassica napus L.) and to develop a first approximation of its critical phosphorus concentration (P c ) in shoot biomass. An experiment with four rates of P fertilizer (0, 20, 40, and 80 kg P ha −1 ) was conducted on soils with a low available P content at 5 site‐years [Normandin (QC; 2010, 2011, 2012) and Brandon (MB; 2010, 2012)] in Canada. Dry matter (DM) yield, and N and P concentrations were measured weekly on 5 d from early bolting to late flowering, and seed yield was measured at harvest. Seed yield was significantly increased by P fertilization at only 1 of the 5 site‐years, even though a positive response was expected at all site‐years. Phosphorus fertilization did not affect shoot growth and P uptake at any of the 5 site‐years. However, the estimated shoot biomass on the first sampling day was reduced with no P application at 3 of the 5 site‐years. A reduction in early crop growth of more than 30%, however, was required to affect seed yield. The whole‐plant canola P c was expressed as function of N concentration (P c = 1.74 + 0.024N, R 2 = 0.24, P = 0.05) but this first approximation requires further validation.
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Claims 5
Claim · model-written summary
P fertilization significantly increased canola seed yield at only 1 of the 5 site-years.
- Taxon
- Canola
.jpg?width=60)
Brassica napus var. napust0 - Treatment
- P fertilizatione0
- Outcome
- Seed yielde0
- Direction
- increasede0
- Qualifier
- at only 1 of the 5e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“Canola”
e0“Seed yield was significantly increased by P fertilization at only 1 of the 5”
Claim · model-written summary
Phosphorus fertilization did not affect canola shoot growth and P uptake at any of the 5 site-years.
- Taxon
- CanolaBrassica napus var. napust0
- Treatment
- Phosphorus fertilizatione0
- Outcome
- shoot growth and P uptakee0
- Direction
- did not affecte0
- Qualifier
- at any of the 5e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Canola”
e0“Phosphorus fertilization did not affect shoot growth and P uptake at any of the 5”
Claim · model-written summary
The estimated shoot biomass of canola on the first sampling day was reduced with no P application at 3 of the 5 site-years.
- Taxon
- CanolaBrassica napus var. napust0
- Treatment
- no P applicatione0
- Outcome
- estimated shoot biomass on the first sampling daye0
- Direction
- reducede0
- Qualifier
- at 3 of the 5e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Canola”
e0“the estimated shoot biomass on the first sampling day was reduced with no P application at 3 of the 5”
Claim · model-written summary
A reduction in early canola growth of more than 30% was required to affect seed yield.
- Taxon
- CanolaBrassica napus var. napust0
- Outcome
- seed yielde0
- Value
- more than 30%e0
- Qualifier
- reduction in early crop growth of more than 30%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Canola”
e0“A reduction in early crop growth of more than 30%, however, was required to affect seed yield”
Claim · model-written summary
The whole-plant canola critical P concentration (Pc) was expressed as a function of N concentration as Pc = 1.74 + 0.024N (R2 = 0.24, P = 0.05); this first approximation requires further validation.
- Taxon
- CanolaBrassica napus var. napust0
- Outcome
- P ce0
- Value
- P c = 1.74 + 0.024Ne0
- Qualifier
- this first approximation requires further validatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Canola”
e0“canola P c was expressed as function of N concentration (P c = 1.74 + 0.024N, R 2 = 0.24, P = 0.05)”
e1“this first approximation requires further validation”
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