Abstract
Non-destructive assessment of plant nitrogen (N) status is essential for efficient crop production and N management in intensive rice (Oryza sativa L.) cropping systems. Chlorophyll meter (SPAD-502) has been widely used as a rapid, non-destructive and cost-effective diagnostic tool for in-season assessment of crop N status. The present study was intended to establish the quantitative relationships between chlorophyll meters readings, plant N concentration (PNC), N nutrition index (NNI), accumulated N deficit (AND), and N requirement (NR), as well as to compare the stability of these relationships at different vegetative growth stages in Japonica and Indica rice cultivars. Seven multi-locational field experiments using varied N rates and seven rice cultivars were conducted in east China. The results showed that the PNC and chlorophyll meters readings increased with increasing N application rates across the cultivars, growing seasons, and sites. The PNC and chlorophyll meters readings under varied N rates ranged from 2.29 to 3.21, 1.06 to 1.82 and 37.10 to 45.4 and 37.30 to 46.6, respectively, at TL and HD stages for Japonica rice cultivars, while they ranged from 2.25 to 3.23, 1.34 to 1.91 and 35.6 to 43.3 and 37.3 to 45.5 for Indica rice cultivars, respectively. The quantitative relationships between chlorophyll meters readings, PNC, NNI, AND, and NR established at different crop growth stages in two rice ecotypes, were highly significant with R2 values ranging from 0.69 to 0.93 and 0.71 to 0.86 for Japonica and Indica rice, respectively. The strongest relationships were observed for AND and NR at panicle initiation and booting stages in both rice ecotypes. The validation of the relationships developed in the present study with an independent data exhibited a solid model performance and confirmed their robustness as a reliable and rapid diagnostic tool for in-season estimation of plant N parameters for sustainable N management in rice. The results of this study will offer a suitable approach for managing N application precisely during the growth period of the rice crop in intensive rice cropping systems in east China.
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Claims 5
Claim · model-written summary
Plant N concentration and chlorophyll meter readings increased with increasing N application rates across cultivars, seasons and sites.
- Taxon
- Rice
Oryza sativat0 - Treatment
- increasing N application ratese2
- Outcome
- PNC and chlorophyll meters readingse2
- Direction
- increasede2
- Setting
- east Chinae1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Measurements in Rice”
e1“Seven multi-locational field experiments using varied N rates and seven rice cultivars were conducted in east China”
e2“The results showed that the PNC and chlorophyll meters readings increased with increasing N application rates across the cultivars, growing seasons, and sites”
Claim · model-written summary
Quantitative relationships between chlorophyll meter readings, PNC, NNI, AND and NR were highly significant, with R2 of 0.69 to 0.93 in Japonica and 0.71 to 0.86 in Indica rice.
- Taxon
- RiceOryza sativat0
- Material
- Japonica and Indica ricee3
- Organ / stage
- different crop growth stagese3
- Outcome
- quantitative relationships between chlorophyll meters readings, PNC, NNI, AND, and NRe3
- Value
- 0.69 to 0.93 and 0.71 to 0.86e3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Measurements in Rice”
e3“The quantitative relationships between chlorophyll meters readings, PNC, NNI, AND, and NR established at different crop growth stages in two rice ecotypes, were highly significant with R2 values ranging from 0.69 to 0.93 and 0.71 to 0.86 for Japonica and Indica rice, respectively”
Claim · model-written summary
The strongest relationships in rice were for AND and NR at panicle initiation and booting stages in both ecotypes.
- Taxon
- RiceOryza sativat0
- Material
- both rice ecotypese4
- Organ / stage
- panicle initiation and booting stagese4
- Outcome
- AND and NRe4
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Measurements in Rice”
e4“The strongest relationships were observed for AND and NR at panicle initiation and booting stages in both rice ecotypes”
Claim · model-written summary
The validation with independent data showed solid model performance, confirming the relationships as a reliable and rapid diagnostic tool for in-season estimation of plant N parameters in rice.
- Taxon
- RiceOryza sativat0
- Outcome
- model performancee5
- Comparator
- an independent datae5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Measurements in Rice”
e5“The validation of the relationships developed in the present study with an independent data exhibited a solid model performance and confirmed their robustness as a reliable and rapid diagnostic tool for in-season estimation of plant N parameters”
Claim · model-written summary
The relationships offer a suitable approach for managing N application precisely during the rice growth period.
- Taxon
- RiceOryza sativat0
- Outcome
- managing N applicatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Measurements in Rice”
e6“The results of this study will offer a suitable approach for managing N application precisely during the growth period of the rice crop”
The same questions in other papers
nitrogen · nutrient: content · Oryza sativa (rice)Positive and negative results
408 papers in the same direction as this paper · 52 in the opposite direction · 3 reporting no difference from an alternative
- positive
- negative
- no effect
460 papers more in this group
See all 464 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.