Abstract
Cassava is growing in importance in Nigeria as a food and industrial crop. Current yields are low due to poor soil fertility and because farmers do not use improved germplasm, clean planting material, or improved crop management in Nigeria. To provide feasible agronomic recommendations targeting increased root yield, the effects of tillage intensity, fertilizer application, plant density and weed control were tested in 230 farmers’ fields in southwestern Nigeria over two years. In 2016, tillage treatments were zero, single and double passage with a disc plough, followed by ridging (soil shaping) versus leaving the soil flat. Fertilizer application at 75:20:90 kg ha−1 NPK was tested against a control and two plant densities (10,000 versus 12,500 ha−1) were compared. In 2017, plant density at 10,000 ha−1 and double plough were excluded, while pre- and post-emergence herbicide application versus farmer’s choice of weed control (i.e. manual weeding using hand hoe) was introduced. Cassava was harvested at 12 months after planting, and yields were recorded as fresh root mass. In 2016, double plough (15.9 Mg ha−1) had a minor advantage over single plough (14.3 Mg ha−1), while zero plough produced 12.9 Mg ha−1 (P < 0.001). Ridging increased yield significantly (P < 0.01) by 2.3 Mg ha−1 after single and zero plough, but not after double plough. Across tillage treatments, planting at 12,500 plants ha−1 and fertilizer application increased yields by 1.5 and 4.2 Mg ha−1, respectively. In 2017, ridging resulted in a yield increase of 1.7 Mg ha−1 after single plough and 5.6 Mg ha−1 after zero plough. Fertilizer application increased root yield by 2.9 Mg ha-1 across tillage treatments. The use of herbicides negatively affected cassava yields in zero plough fields, compared with manual weeding. After ploughing, yield in herbicide based and manual weed control were not different. Cassava root yield response to tillage intensity strongly varied across fields, with low-yielding fields commonly responding less frequently to tillage. We conclude that unresponsive fields require measures other than increased tillage intensity to increase cassava root yields and that cost-intensive tillage operations must be targeted to responsive fields together with fertilizer application and improved weed control.
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Claims 14
Claim · model-written summary
Double plough yielded 15.9 Mg ha−1, versus 14.3 after single plough and 12.9 after zero plough in 2016.
- Taxon
- cassava
Manihot esculentat0 - Treatment
- double ploughe0
- Outcome
- cassava root yieldt0
- Direction
- advantagee0
- Value
- 15.9 Mg ha−1e0
- Qualifier
- 14.3 Mg ha−1e0
- Comparator
- single ploughe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 2016, double plough (15.9 Mg ha−1) had a minor advantage over single plough (14.3 Mg ha−1), while zero plough produced 12.9 Mg ha−1 (P < 0.001).”
t0“cassava root yield”
Claim · model-written summary
Zero plough yielded 12.9 Mg ha−1 in 2016.
- Taxon
- cassavaManihot esculentat0
- Treatment
- zero ploughe0
- Outcome
- cassava root yieldt0
- Value
- 12.9 Mg ha−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“zero plough produced 12.9 Mg ha−1 (P < 0.001)”
t0“cassava root yield”
Claim · model-written summary
Ridging increased yield by 2.3 Mg ha−1 after single and zero plough.
- Taxon
- cassavaManihot esculentat0
- Treatment
- Ridginge0
- Outcome
- yielde0
- Direction
- increasede0
- Value
- 2.3 Mg ha−1e0
- Qualifier
- after single and zero ploughe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ridging increased yield significantly (P < 0.01) by 2.3 Mg ha−1 after single and zero plough”
t0“cassava root yield”
Claim · model-written summary
Ridging did not increase yield after double plough.
- Taxon
- cassavaManihot esculentat0
- Treatment
- Ridginge1
- Outcome
- yielde1
- Qualifier
- double ploughe1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but not after double plough.”
e1“Ridging increased yield significantly (P < 0.01) by 2.3 Mg ha−1 after single and zero plough, but not after double plough.”
t0“cassava root yield”
Claim · model-written summary
Higher planting density raised yield by 1.5 Mg ha−1 across tillage treatments.
- Taxon
- cassavaManihot esculentat0
- Treatment
- planting at 12,500 plants ha−1e0
- Outcome
- yieldse0
- Direction
- increasede0
- Value
- 1.5e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“planting at 12,500 plants ha−1 and fertilizer application increased yields by 1.5 and 4.2 Mg ha−1, respectively”
t0“cassava root yield”
Claim · model-written summary
Fertilizer increased yield by 4.2 Mg ha−1 across tillage treatments in 2016.
- Taxon
- cassavaManihot esculentat0
- Treatment
- fertilizer applicatione0
- Outcome
- yieldse0
- Direction
- increasede0
- Value
- 4.2 Mg ha−1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fertilizer application increased yields by 1.5 and 4.2 Mg ha−1, respectively”
t0“cassava root yield”
Claim · model-written summary
In 2017 ridging raised yield by 1.7 Mg ha−1 after single plough.
- Taxon
- cassavaManihot esculentat0
- Treatment
- ridginge0
- Outcome
- yielde0
- Direction
- increasee0
- Value
- 1.7 Mg ha−1e0
- Qualifier
- after single ploughe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 2017, ridging resulted in a yield increase of 1.7 Mg ha−1 after single plough and 5.6 Mg ha−1 after zero plough.”
t0“cassava root yield”
Claim · model-written summary
In 2017 ridging raised yield by 5.6 Mg ha−1 after zero plough.
- Taxon
- cassavaManihot esculentat0
- Treatment
- ridginge0
- Outcome
- yielde0
- Direction
- increasee0
- Value
- 5.6 Mg ha−1e0
- Qualifier
- after zero ploughe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In 2017, ridging resulted in a yield increase of 1.7 Mg ha−1 after single plough and 5.6 Mg ha−1 after zero plough.”
t0“cassava root yield”
Claim · model-written summary
Fertilizer raised root yield by 2.9 Mg ha-1 in 2017.
- Taxon
- cassavaManihot esculentat0
- Treatment
- Fertilizer applicatione0
- Outcome
- root yielde0
- Direction
- increasede0
- Value
- 2.9 Mg ha-1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilizer application increased root yield by 2.9 Mg ha-1 across tillage treatments.”
t0“cassava root yield”
Claim · model-written summary
Herbicides lowered cassava yield versus manual weeding in zero-plough fields.
- Taxon
- cassavaManihot esculentae0
- Treatment
- herbicidese0
- Outcome
- cassava yieldse0
- Direction
- negatively affectede0
- Qualifier
- zero plough fieldse0
- Comparator
- manual weedinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The use of herbicides negatively affected cassava yields in zero plough fields, compared with manual weeding.”
Claim · model-written summary
Herbicide and manual weed control yielded similarly after ploughing.
- Taxon
- cassavaManihot esculentat0
- Treatment
- herbicide basede0
- Outcome
- yielde0
- Direction
- not differente0
- Comparator
- manual weed controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After ploughing, yield in herbicide based and manual weed control were not different.”
t0“cassava root yield”
Claim · model-written summary
Cassava yield response to tillage varied strongly among fields.
- Taxon
- CassavaManihot esculentae0
- Outcome
- root yield response to tillage intensitye0
- Direction
- variede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cassava root yield response to tillage intensity strongly varied across fields”
Claim · model-written summary
Low-yielding fields responded less often to tillage.
- Taxon
- cassavaManihot esculentat0
- Outcome
- respondinge0
- Direction
- less frequentlye0
- Setting
- low-yielding fieldse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low-yielding fields commonly responding less frequently to tillage”
t0“cassava root yield”
Claim · model-written summary
The authors recommend targeting costly tillage to responsive fields with fertilizer and improved weed control.
- Taxon
- cassavaManihot esculentat0
- Outcome
- cost-intensive tillage operations must be targeted to responsive fields together with fertilizer application and improved weed controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cost-intensive tillage operations must be targeted to responsive fields together with fertilizer application and improved weed control”
t0“cassava root yield”
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