Abstract
Most soils used for agriculture in south-western Australia are sandy and are now deficient in both potassium (K) and nitrogen (N) for cereal and canola (oilseed rape; Brassica napus L.) grain production. However, the effect of applying different levels of both fertiliser K and N on grain yields of these crops is not known. We report results of 10 field experiments, conducted on sandy soils in the region, to measure the effects of applying both K and N on canola grain yields and concentration of oil and protein in grain. Four levels of K (0–60 kg K/ha as potassium chloride) and four levels of N (0–138 kg N/ha as urea) were applied. Significant grain yield responses to applied N occurred in all experiments for the nil-K treatment and each level of K applied, with responses increasing as more N was applied. For all levels of N applied, significant grain yield responses occurred when up to 30 kg K/ha was applied, with no further significant grain yield responses occurring when 60 kg K/ha was applied. The K × N interaction was always significant for grain production. Application of K had no effect on the concentration of oil and protein in grain. Application of N consistently decreased concentration of oil and increased concentration of protein in grain. The K × N interaction was not significant for concentration of oil or protein in grain, but application of up to 30 kg K/ha significantly increased canola grain and so oil yields (concentration of oil in grain multiplied by grain yield). Our results are likely to be relevant for all acidic to neutral sandy soils worldwide used for growing canola crops.
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Claims 10
Claim · model-written summary
Applied N significantly increased grain yield at each K level.
- Taxon
- canola
.jpg?width=60)
Brassica napus var. napust0 - Treatment
- applied Ne0
- Outcome
- grain yielde0
- Direction
- increasinge0
- Comparator
- nil-K treatment and each level of K appliede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“canola (Brassica napus L.)”
e0“Significant grain yield responses to applied N occurred in all experiments for the nil-K treatment and each level of K applied, with responses increasing as more N was applied.”
Claim · model-written summary
K up to 30 kg K/ha significantly increased grain yield at all N levels.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- up to 30 kg K/hae0
- Outcome
- grain yielde0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“For all levels of N applied, significant grain yield responses occurred when up to 30 kg K/ha was applied”
Claim · model-written summary
K at 60 kg K/ha produced no further significant grain yield response.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- 60 kg K/hae0
- Outcome
- grain yield responsese0
- Direction
- no furthere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“with no further significant grain yield responses occurring when 60 kg K/ha was applied.”
Claim · model-written summary
K and N interacted significantly for grain production.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- K × Ne0
- Outcome
- grain productione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“The K × N interaction was always significant for grain production.”
Claim · model-written summary
K application did not change grain oil concentration.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- Application of Ke0
- Outcome
- concentration of oile0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“Application of K had no effect on the concentration of oil and protein in grain.”
Claim · model-written summary
K application did not change grain protein concentration.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- Application of Ke0
- Outcome
- protein in graine0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“Application of K had no effect on the concentration of oil and protein in grain.”
Claim · model-written summary
N application decreased grain oil concentration.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- Application of Ne0
- Outcome
- concentration of oile0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“Application of N consistently decreased concentration of oil and increased concentration of protein in grain.”
Claim · model-written summary
N application increased grain protein concentration.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- Application of Ne0
- Outcome
- concentration of protein in graine0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“Application of N consistently decreased concentration of oil and increased concentration of protein in grain.”
Claim · model-written summary
K and N did not significantly interact for grain oil or protein concentration.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- K × Ne0
- Outcome
- concentration of oil or protein in graine0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“The K × N interaction was not significant for concentration of oil or protein in grain”
Claim · model-written summary
K up to 30 kg K/ha significantly increased grain and oil yields.
- Taxon
- canolaBrassica napus var. napust0
- Treatment
- up to 30 kg K/hae0
- Outcome
- grain and so oil yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“canola (Brassica napus L.)”
e0“application of up to 30 kg K/ha significantly increased canola grain and so oil yields”
The same questions in other papers
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See all 22 papers →nitrogen · quality: protein · Brassica napus (oilseed rape)Positive and negative results
33 papers in the same direction as this paper · 3 in the opposite direction
- positive
- negative
- no effect
33 papers more in this group
See all 37 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.