Document Type

Article

Publication Date

1-2021

Keywords

amino-acids; accumulation; nitrate; emissions; plants; n-15

Abstract

No post-season analysis method currently exists for rice (Oryza sativa L.) to determine whether N was managed properly during the growing season. Our primary research objective was to determine whether post-season, rice stem N concentrations can be used to predict if sufficient or excessive N was available. Aboveground biomass samples were taken from N response trials at harvest. Stalks were separated into 5-cm segments starting at the soil surface and extending upward to 45 cm. One-half of the samples had all of the leaf material (leaves and leaf sheaths) removed, whereas the other half remained intact. All samples were analyzed for N concentration in the form of amino acids (AA-N), ammonium (NH4+-N), and nitrate (NO3--N). Samples analyzed with leaf material were found to be statistically different from samples analyzed without leaf material for all three forms of N (P < .0001). Due to significant variability in response, AA-N and NH4+-N were discovered to be incompatible for a post-season tissue test in rice. However, NO3--N concentrations showed strong consistency in response to N fertilization rates. Upon further analysis, NO3--N concentrations in the lower portion of the rice stem were found to be more responsive to excessive N fertilization than the upper sections of the rice stem (P < .0001). These results suggest that rice stalks sampled from the lower portion of the plant near maturity and analyzed for NO3--N could be used to predict over-fertilization and should be investigated further.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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