Abstract
SUMMARY An evaluation was conducted in eastern India over three years, 2005–2007, to compare the performance of certain System of Rice Intensification (SRI) practices: transplanting single, young (10-day-old) seedlings in a square pattern; no continuous flooding; and use of a mechanical weeder – with those currently endorsed by the Central Rice Research Institute of India, referred to here as recommended management practices (RMP). All plots received the same fertilization, a combination of organic and inorganic nutrients, and the SRI spacing used was 20% less than usually recommended. Accordingly, the results reported here are designated as a modification of SRI recommendations (SRI m ). The objective of this research was to understand the benefits in terms of yield and other physiological parameters, if any, from using most if not all recommended SRI practices compared to RMP. These selected SRI practices out-yielded RMP by 42%, with the higher yield associated with various phenotypical alterations, which are reported here. Significant measurable changes were observed in physiological processes and plant characteristics, such as longer panicles, more grains panicle −1 and higher % of grain-filling. The decreased plant density with SRI m management was compensated for by increased per-plant productivity. SRI m hills with single plants were found to have deeper and better-distributed root systems, higher xylem exudation rates, more open plant architecture with more erect and larger leaves, and more tillers than did RMP hills having multiple plants. Due to the reduction in number of hills m −2 in SRI m plots compared to RMP, no significant difference was found in root dry weight or leaf number, tillers or panicle number on an area basis. Nevertheless, in spite of SRI m having fewer hills and fewer tillers per unit area, the leaf area index (LAI) with SRI m practice was greater due to larger leaves. These together with altered plant architecture, contributed to more light interception by SRI m plants. The higher leaf chlorophyll content at ripening stage reflected delayed senescence and the greater fluorescence efficiency (Fv/Fm and ФPS II) associated with SRI m practices contributed to more efficient utilization of light and a higher rate of photosynthesis, which was probably responsible for the observed increase in grain filling and heavier grains compared to RMP plants. The higher photosynthesis rate coupled with lower transpiration in SRI m plants indicated that they were using water more efficiently than did RMP plants. The latter produced 1.6 μ mol CO 2 fixed per m mol water transpired, compared to 3.6 μ mol CO 2 in SRI m plants.
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Claims 15
Claim · model-written summary
Selected SRI practices out-yielded RMP by 42%.
- Taxon
- RICE
Oryza sativat0 - Treatment
- selected SRI practicese0
- Outcome
- yieldede0
- Direction
- out-yieldede0
- Comparator
- RMPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These selected SRI practices out-yielded RMP by 42%”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI produced longer panicles, more grains per panicle, and higher grain filling.
- Taxon
- RICEOryza sativat0
- Outcome
- longer panicles, more grains panicle −1 and higher % of grain-fillinge0
- Direction
- longere0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Significant measurable changes were observed in physiological processes and plant characteristics, such as longer panicles, more grains panicle −1 and higher % of grain-filling”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants had deeper and better distributed roots.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI me0
- Outcome
- root systemse0
- Direction
- deeper and better-distributede0
- Comparator
- RMPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SRI m hills with single plants were found to have deeper and better-distributed root systems, higher xylem exudation rates, more open plant architecture with more erect and larger leaves, and more tillers than did RMP hills having multiple plants”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants had higher xylem exudation rates.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI me0
- Outcome
- xylem exudation ratese0
- Direction
- highere0
- Comparator
- RMPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SRI m hills with single plants were found to have deeper and better-distributed root systems, higher xylem exudation rates, more open plant architecture with more erect and larger leaves, and more tillers than did RMP hills having multiple plants”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants had more open architecture and larger leaves.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI me0
- Outcome
- plant architecture with more erect and larger leavese0
- Direction
- more opene0
- Comparator
- RMPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SRI m hills with single plants were found to have deeper and better-distributed root systems, higher xylem exudation rates, more open plant architecture with more erect and larger leaves, and more tillers than did RMP hills having multiple plants”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants had more tillers per hill.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SRI m hills with single plants were found to have deeper and better-distributed root systems, higher xylem exudation rates, more open plant architecture with more erect and larger leaves, and more tillers than did RMP hills having multiple plants”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
Root dry weight, leaf number, tillers and panicle number per area did not differ significantly.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI m plotse0
- Outcome
- root dry weight or leaf number, tillers or panicle number on an area basise0
- Direction
- no significant differencee0
- Comparator
- RMPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Due to the reduction in number of hills m −2 in SRI m plots compared to RMP, no significant difference was found in root dry weight or leaf number, tillers or panicle number on an area basis”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI had greater leaf area index due to larger leaves.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI m practicee0
- Outcome
- leaf area index (LAI)e0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the leaf area index (LAI) with SRI m practice was greater due to larger leaves”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants intercepted more light.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI m plantse0
- Outcome
- light interceptione0
- Direction
- moree0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These together with altered plant architecture, contributed to more light interception by SRI m plants”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI had higher leaf chlorophyll at ripening.
- Taxon
- RICEOryza sativat0
- Outcome
- leaf chlorophyll content at ripening stagee0
- Direction
- highere0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The higher leaf chlorophyll content at ripening stage reflected delayed senescence”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI had greater fluorescence efficiency.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI m practicese0
- Outcome
- fluorescence efficiency (Fv/Fm and ФPS II)e0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the greater fluorescence efficiency (Fv/Fm and ФPS II) associated with SRI m practices”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants had higher photosynthesis.
- Taxon
- RICEOryza sativat0
- Outcome
- rate of photosynthesise0
- Direction
- highere0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a higher rate of photosynthesis”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants had heavier grains than RMP plants.
- Taxon
- RICEOryza sativat0
- Outcome
- grainse0
- Direction
- heaviere0
- Comparator
- RMPe0
Not reportedTreatment
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“heavier grains compared to RMP plants”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants had lower transpiration.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI m plantse0
- Outcome
- transpiratione0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lower transpiration in SRI m plants”
t0“SYSTEM OF RICE INTENSIFICATION”
Claim · model-written summary
SRI plants fixed more CO2 per unit water transpired.
- Taxon
- RICEOryza sativat0
- Treatment
- SRI m plantse0
- Outcome
- CO 2 fixed per m mol water transpirede0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The latter produced 1.6 μ mol CO 2 fixed per m mol water transpired, compared to 3.6 μ mol CO 2 in SRI m plants”
t0“SYSTEM OF RICE INTENSIFICATION”
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