Mainak Ghosh
SPAD Chlorophyll Meter-Based Real-Time Nitrogen Management in Manure-Amended Lowland Rice
Ghosh, Mainak; Roychowdhury, Arnab; Dutta, Swaraj Kumar; Hazra, Kali Krishna; Singh, Garima; Kohli, Anshuman; Kumar, Sanjay; Acharya, Shivashankar; Mandal, Jajati; Singh, Yanendra Kumar; Pathak, Sushil Kumar; Gupta, Sanjeev Kumar
Authors
Arnab Roychowdhury
Swaraj Kumar Dutta
Kali Krishna Hazra
Garima Singh
Anshuman Kohli
Sanjay Kumar
Shivashankar Acharya
Dr Jajati Mandal J.Mandal2@salford.ac.uk
University Fellow
Yanendra Kumar Singh
Sushil Kumar Pathak
Sanjeev Kumar Gupta
Abstract
Precise adjustment of timing and dosage of fertilizer nitrogen (N) under real-time nitrogen management (RTNM) is crucial to maximize benefits. The study aimed to assess and recommend the best combination of threshold SPAD-502 chlorophyll meter reading (SCMR) and top dressing N rate for lowland flooded rice, amended with farmyard manure 5 t ha−1, to maximize yield, N use efficiency, and economic gains. In optimization trial, four SCMR-based N scheduling (SCMR34, SCMR36, SCMR38, SCMR40), each with three top dressing N rates (15, 20, 25 kg N ha−1) as RTNM treatments, were evaluated for crop growth and yield, nutrient use efficiency, simulated N2O emission, and economics, comparing with fixed-time N management (FTNM) (100 kg N ha−1, 4 splits). Subsequently, the best-fit SCMR treatment was validated across seven rice cultivars. Top dressing of 20 kg N ha−1 at ≤ SCMR 38 (SCMR38N20) led to a higher yield (+ 8%), N use efficiency (+ 43%), net return (+ 11%), and reduced N input (− 18%) compared to FTNM. The yield advantage with SCMR38N20 was attributed to higher internal N use efficiency and optimal source–sink balance (higher harvest index). In validation trial, the best-fit RTNM treatment (SCMR38N20) showed yield advantage (+ 7%), but significant for four out of seven cultivars. In lowland rice production, the RTNM with top dressing of 20 kg N ha−1 at ≤ SCMR38 can increase yield of medium duration cultivar (Rajendra Swata) and N use efficiency. However, cultivar-specific adjustments to the SCMR threshold and N rate are equally important for significant yield advantage.
Journal Article Type | Article |
---|---|
Acceptance Date | Aug 25, 2023 |
Online Publication Date | Sep 5, 2023 |
Deposit Date | Sep 16, 2023 |
Publicly Available Date | Sep 6, 2024 |
Journal | Journal of Soil Science and Plant Nutrition |
Print ISSN | 0718-9508 |
Electronic ISSN | 0718-9516 |
Publisher | Springer |
Peer Reviewed | Peer Reviewed |
DOI | https://doi.org/10.1007/s42729-023-01457-3 |
Keywords | Plant Science; Soil Science; Agronomy and Crop Science |
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