Abstract
Abstract Optimal potassium (K) fertilization is beneficial for oilseed‐rape ( Brassica napus L.) yield and quality. However, the discrepancy between the high K demand of winter oilseed rape and low soil fertility and insufficient potassium input has limited the sustainable development of oilseed‐rape production. A series of on‐farm experiments in the key winter oilseed‐rape domains of China was conducted from 2004 to 2010 to evaluate K‐fertilizer management for winter oilseed rape. Currently, the average NH 4 OAc‐extractable K content in the 0–20 cm soil layer is 89.1 mg kg –1 indicative of “slight deficiency”. In addition, farmers in China usually fail to use sufficient K fertilizer in oilseed‐rape production, the average mineral‐potassium‐fertilizer input in 2010 being only 35 kg K ha –1 , far lower than the recommended rate of potassium for winter oilseed rape. Adequate potassium fertilization significantly raises seed yield. The average yield‐increase rate for the major production regions due to K‐fertilizer application was 18.5%, and the average K fertilizer–use efficiency 36.1%. Based on the negative correlation between yield response to potassium fertilization and available soil K content, a soil‐K‐test index was established for winter oilseed rape with a threshold value for NH 4 OAc‐extractable soil K of 135 mg kg –1 . When available soil K‐content is below this threshold value, more K fertilizer should be applied to achieve high seed yield and to increase soil fertility. The major challenge for K‐fertilizer management in winter oilseed‐rape production in China will be to guide farmers in the different regions in making reasonable use of K fertilizer through soil K‐testing technology in order to maintain both seed yield and soil fertility.
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Claims 8
Claim · model-written summary
Mean extractable soil potassium was 89.1 mg kg –1, indicating slight deficiency.
- Taxon
- winter oilseed‐rape
_Brassica_napus_-_Habit.jpg?width=60)
Brassica napust0 - Outcome
- NH 4 OAc‐extractable K contente0
- Value
- 89.1 mg kg –1e0
- Qualifier
- slight deficiencye0
Not reportedOrgan / stage
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Brassica_napus_-_Habit.jpg?width=500)
Verbatim
e0“average NH 4 OAc‐extractable K content in the 0–20 cm soil layer is 89.1 mg kg –1 indicative of “slight deficiency””
t0“winter oilseed‐rape”
Claim · model-written summary
Mean mineral potassium input in 2010 was 35 kg K ha –1.
- Taxon
- winter oilseed‐rapeBrassica napust0
- Outcome
- mineral‐potassium‐fertilizer inpute0
- Value
- 35 kg K ha –1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“average mineral‐potassium‐fertilizer input in 2010 being only 35 kg K ha –1”
t0“winter oilseed‐rape”
Claim · model-written summary
Potassium fertilization significantly raised seed yield.
- Taxon
- winter oilseed‐rapeBrassica napust0
- Treatment
- potassium fertilizatione0
- Outcome
- seed yielde0
- Direction
- raisese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Adequate potassium fertilization significantly raises seed yield.”
t0“winter oilseed‐rape”
Claim · model-written summary
Potassium application increased yield by 18.5% on average in the major production regions.
- Taxon
- winter oilseed‐rapeBrassica napust0
- Treatment
- K‐fertilizer applicatione0
- Outcome
- yield‐increase ratee0
- Direction
- increasee0
- Value
- 18.5%e0
- Setting
- major production regionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average yield‐increase rate for the major production regions due to K‐fertilizer application was 18.5%”
t0“winter oilseed‐rape”
Claim · model-written summary
Average potassium fertilizer use efficiency was 36.1%.
- Taxon
- winter oilseed‐rapeBrassica napust0
- Outcome
- K fertilizer–use efficiencye0
- Value
- 36.1%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“average K fertilizer–use efficiency 36.1%”
t0“winter oilseed‐rape”
Claim · model-written summary
Yield response to potassium fertilization was negatively correlated with available soil potassium.
- Taxon
- winter oilseed‐rapeBrassica napust0
- Outcome
- yield response to potassium fertilizatione0
- Direction
- negativee0
- Setting
- available soil K contente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“negative correlation between yield response to potassium fertilization and available soil K content”
t0“winter oilseed‐rape”
Claim · model-written summary
The soil potassium test index threshold was 135 mg kg –1.
- Taxon
- winter oilseed rapeBrassica napuse0
- Outcome
- soil‐K‐test indexe0
- Value
- 135 mg kg –1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a soil‐K‐test index was established for winter oilseed rape with a threshold value for NH 4 OAc‐extractable soil K of 135 mg kg –1”
Claim · model-written summary
The authors recommend more potassium fertilizer below the soil potassium threshold.
- Taxon
- winter oilseed‐rapeBrassica napust0
- Outcome
- more K fertilizer should be appliede0
- Qualifier
- below this threshold valuee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When available soil K‐content is below this threshold value, more K fertilizer should be applied to achieve high seed yield and to increase soil fertility.”
t0“winter oilseed‐rape”
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See all 378 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.