Abstract
Mean grain yield of flooded rice in southern Brazil has increased in recent years due to the use of high-yield cultivars and improvement of crop management practices. Nevertheless, stagnation in grain yields has been observed in some rice-producing regions. Adoption of conservation tillage systems based on cover crops may be a strategy to increase rice grain yield potential. The objective of the present study was to evaluate the effect of winter cover crops on initial establishment, development, and grain yield of flooded rice (Oryza sativa L.) grown under different fertilization levels and no-tillage. A field experiment was carried out for three consecutive years (2010/11, 2011/12, and 2012/13) in Cachoeirinha, Rio Grande do Sul, South Brazil. Treatments included three winter cover crops [ryegrass (Lolium multiflorum Lam.), native serradella (Ornithopus micranthus Benth.), and a ryegrass-serradella mixture] and fallow, and three fertilization levels for rice grown in succession. More than 3 Mg ha−1 of serradella aboveground residue or 4 Mg ha−1 of ryegrass residue limited rice emergence in the first year when rainfall in the sowing-emergence period was higher than in the second and third years. In contrast, a large amount of residue (serradella >2 Mg ha−1; ryegrass >3 Mg ha−1) was beneficial to rice emergence when rainfall was low in the sowing-emergence period of the second and third years. The serradella cover crop increased rice aboveground biomass at anthesis by 22 % compared to the ryegrass cover crop. Furthermore, rice grain yield was 15 % higher in succession to serradella than to ryegrass in the third year. Continuous cultivation of flooded rice in succession to ryegrass over three years reduced grain yield by around 1.4 Mg ha−1, regardless of fertilization level. Fertilization for very high production expectations increased rice grain yield in all years, especially in the second year, when solar radiation was higher than normal. The use of winter cover crops affected plant emergence, aboveground biomass, and grain yield of flooded rice. Rice grain yield increased with increases in fertilization level, and this response was not affected by the previous cover crop.
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Claims 9
Claim · model-written summary
High serradella residue limited rice emergence in the rainy first year.
- Taxon
- rice
Oryza sativae0 - Treatment
- More than 3 Mg ha−1 of serradella aboveground residuee0
- Outcome
- rice emergencee0
- Direction
- limitede0
- Qualifier
- first year when rainfall in the sowing-emergence period was highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“More than 3 Mg ha−1 of serradella aboveground residue or 4 Mg ha−1 of ryegrass residue limited rice emergence in the first year when rainfall in the sowing-emergence period was higher than in the second and third years”
Claim · model-written summary
High ryegrass residue limited rice emergence in the rainy first year.
- Taxon
- riceOryza sativae0
- Treatment
- 4 Mg ha−1 of ryegrass residuee0
- Outcome
- rice emergencee0
- Direction
- limitede0
- Qualifier
- first year when rainfall in the sowing-emergence period was highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“More than 3 Mg ha−1 of serradella aboveground residue or 4 Mg ha−1 of ryegrass residue limited rice emergence in the first year when rainfall in the sowing-emergence period was higher than in the second and third years”
Claim · model-written summary
Serradella residue above 2 Mg ha−1 benefited rice emergence under low rainfall.
- Taxon
- riceOryza sativae0
- Treatment
- serradella >2 Mg ha−1e0
- Outcome
- rice emergencee0
- Direction
- beneficiale0
- Qualifier
- when rainfall was lowe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a large amount of residue (serradella >2 Mg ha−1; ryegrass >3 Mg ha−1) was beneficial to rice emergence when rainfall was low”
Claim · model-written summary
Ryegrass residue above 3 Mg ha−1 benefited rice emergence under low rainfall.
- Taxon
- riceOryza sativae0
- Treatment
- ryegrass >3 Mg ha−1e0
- Outcome
- rice emergencee0
- Direction
- beneficiale0
- Qualifier
- when rainfall was lowe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a large amount of residue (serradella >2 Mg ha−1; ryegrass >3 Mg ha−1) was beneficial to rice emergence when rainfall was low”
Claim · model-written summary
Serradella increased rice biomass at anthesis by 22 % relative to ryegrass.
- Taxon
- riceOryza sativae0
- Organ / stage
- anthesise0
- Treatment
- serradella cover crope0
- Outcome
- rice aboveground biomasse0
- Direction
- increasede0
- Value
- 22 %e0
- Comparator
- ryegrass cover crope0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The serradella cover crop increased rice aboveground biomass at anthesis by 22 % compared to the ryegrass cover crop”
Claim · model-written summary
Rice yield after serradella was 15 % higher than after ryegrass in year three.
- Taxon
- riceOryza sativae0
- Treatment
- serradellae0
- Outcome
- rice grain yielde0
- Direction
- highere0
- Value
- 15 %e0
- Qualifier
- third yeare0
- Comparator
- ryegrasse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rice grain yield was 15 % higher in succession to serradella than to ryegrass in the third year”
Claim · model-written summary
Three years of rice after ryegrass reduced grain yield by about 1.4 Mg ha−1.
- Taxon
- flooded ricee0
- Treatment
- succession to ryegrass over three yearse0
- Outcome
- grain yielde0
- Direction
- reducede0
- Value
- around 1.4 Mg ha−1e0
- Qualifier
- regardless of fertilization levele0
Not reportedComparator
Verbatim
e0“Continuous cultivation of flooded rice in succession to ryegrass over three years reduced grain yield by around 1.4 Mg ha−1, regardless of fertilization level”
Claim · model-written summary
Fertilization for very high production expectations raised rice yield in all years.
- Taxon
- riceOryza sativae0
- Treatment
- Fertilization for very high production expectationse0
- Outcome
- rice grain yielde0
- Direction
- increasede0
- Qualifier
- in all years, especially in the second yeare0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilization for very high production expectations increased rice grain yield in all years, especially in the second year, when solar radiation was higher than normal”
Claim · model-written summary
Yield response to increased fertilization was unaffected by previous cover crop.
- Taxon
- RiceOryza sativae0
- Treatment
- increases in fertilization levele0
- Outcome
- Rice grain yielde0
- Direction
- increasede0
- Qualifier
- this response was not affected by the previous cover crope0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice grain yield increased with increases in fertilization level, and this response was not affected by the previous cover crop”
The same questions in other papers
cover crop · growth · Oryza sativa (rice)Positive and negative results
4 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
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See all 6 papers →fertilization · yield · Oryza sativa (rice)Positive and negative results
3,182 papers in the same direction as this paper · 207 in the opposite direction · 65 reporting no difference from an alternative
- no effect
- no effect
- negative
3,451 papers more in this group
See all 3,455 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.