Abstract
Core Ideas Cassava is a major food crop in tropical Africa Cassava is efficient in uptake of immobile nutrients. Cassava is highly responsive to applied N. Cassava ( Manihot esculenta Crantz) is a major food crop in Africa with little information of response to applied nutrients. Our objectives were to: determine cassava yield response to macronutrients for production areas in Ghana, Kenya and Tanzania; evaluate the effect Mg, S, Zn and B application; and determine agronomic efficiency (AE) and value cost ratio (VCR) for nutrient application. Fresh storage root yield with no fertilizer averaged 14.4 Mg ha −1 and mean yield increases due to 80 kg ha −1 N applied were 8.1, 6.5 and 9.0 Mg ha −1 in Ghana, Kenya and Tanzania. Storage root yield was increased 93% with P application for Aduma in Ghana and there was a curvilinear to plateau response to K at Wenchi Ghana. No other responses to P and K rates occurred, but an N × P synergism occurred in Tanzania. There were no responses to applied Mg, S, Zn, and B. The VCR for N at all sites was >2 indicating sufficient profit opportunity to make N application attractive to many financially constrained farmers. The mean soil organic C (SOC) was 8 g kg −1 ; the results may lose applicability with much higher SOC soils. Over all trials, application of 80 kg ha −1 N had, on average 8.44 Mg ha −1 increased yield with 105 kg kg −1 agronomic efficiency and 7.8 $ $ −1 profit to cost ratio. The results indicate that cassava is efficient in P and K uptake with restricted and little profit potential for P and K application in these countries, respectively.
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Claims 15
Claim · model-written summary
Unfertilized fresh storage root yield averaged 14.4 Mg ha −1.
Not reportedTaxon
Verbatim
e0“Fresh storage root yield with no fertilizer averaged 14.4 Mg ha −1”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Nitrogen increased yield by 8.1 Mg ha −1 in Ghana.
- Taxon
- Cassava
Manihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mean yield increases due to 80 kg ha −1 N applied were 8.1, 6.5 and 9.0 Mg ha −1 in Ghana, Kenya and Tanzania.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Nitrogen increased yield by 6.5 Mg ha −1 in Kenya.
- Taxon
- CassavaManihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mean yield increases due to 80 kg ha −1 N applied were 8.1, 6.5 and 9.0 Mg ha −1 in Ghana, Kenya and Tanzania.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Nitrogen increased yield by 9.0 Mg ha −1 in Tanzania.
- Taxon
- CassavaManihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“mean yield increases due to 80 kg ha −1 N applied were 8.1, 6.5 and 9.0 Mg ha −1 in Ghana, Kenya and Tanzania.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Phosphorus increased root yield 93% for Aduma in Ghana.
- Taxon
- CassavaManihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Storage root yield was increased 93% with P application for Aduma in Ghana”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Potassium response at Wenchi followed a curvilinear plateau.
- Taxon
- CassavaManihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was a curvilinear to plateau response to K at Wenchi Ghana.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Other P and K rate responses were absent.
- Taxon
- CassavaManihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No other responses to P and K rates occurred”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Nitrogen and phosphorus had a synergistic interaction in Tanzania.
- Taxon
- CassavaManihot esculentat0e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an N × P synergism occurred in Tanzania.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Magnesium, sulfur, zinc and boron applications produced no responses.
- Taxon
- CassavaManihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no responses to applied Mg, S, Zn, and B.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Nitrogen VCR exceeded 2 at all sites.
- Taxon
- CassavaManihot esculentat0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The VCR for N at all sites was >2 indicating sufficient profit opportunity to make N application attractive to many financially constrained farmers.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Mean soil organic carbon was 8 g kg −1.
- Taxon
- CassavaManihot esculentat0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mean soil organic C (SOC) was 8 g kg −1 ; the results may lose applicability with much higher SOC soils.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Across trials, nitrogen increased yield 8.44 Mg ha −1 on average.
- Taxon
- CassavaManihot esculentat0e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Over all trials, application of 80 kg ha −1 N had, on average 8.44 Mg ha −1 increased yield with 105 kg kg −1 agronomic efficiency and 7.8 $ $ −1 profit to cost ratio.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Nitrogen agronomic efficiency was 105 kg kg −1.
- Taxon
- CassavaManihot esculentat0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Over all trials, application of 80 kg ha −1 N had, on average 8.44 Mg ha −1 increased yield with 105 kg kg −1 agronomic efficiency and 7.8 $ $ −1 profit to cost ratio.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
Nitrogen profit to cost ratio was 7.8 $ $ −1.
- Taxon
- CassavaManihot esculentat0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Over all trials, application of 80 kg ha −1 N had, on average 8.44 Mg ha −1 increased yield with 105 kg kg −1 agronomic efficiency and 7.8 $ $ −1 profit to cost ratio.”
t0“Cassava Yield and Economic Response to Fertilizer in Tanzania, Kenya and Ghana”
Claim · model-written summary
The authors conclude cassava efficiently takes up P and K, limiting profit from their application.
- Taxon
- cassavaManihot esculentae0
- Outcome
- P and K uptakee0
- Qualifier
- restricted and little profit potential for P and K applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The results indicate that cassava is efficient in P and K uptake with restricted and little profit potential for P and K application in these countries, respectively.”
The same questions in other papers
phosphorus · yield · Manihot esculenta (cassava)Positive and negative results
17 papers in the same direction as this paper · 2 in the opposite direction
- no effect
- negative
- positive
16 papers more in this group
See all 20 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.