Next Article in Journal
Nitrate–Conductivity Correlations in Aqueous Environments: From Standard Solutions to Natural Water Bodies
Previous Article in Journal
Multivariate Analyses of Soil Properties and CO2 Emissions Under Long-Term Fertilization and Crop Rotation in Luvic Chernozem
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
This is an early access version, the complete PDF, HTML, and XML versions will be available soon.
Article

Optimizing Rice Yield and Heat Stress Resilience Through Nitrogen Top Dressing Before Panicle Emergence

1
Department of International Agricultural Development, Graduate School of Agriculture, Tokyo University of Agriculture, Tokyo 156-8502, Japan
2
Faculty of Agriculture, Nangarhar University, Jalalabad 2601, Afghanistan
3
Faculty of Agriculture, Tokyo University of Agriculture and Technology (TUAT), Saiwai-cho 3-5-8, Fuchu-shi, Tokyo 183-8509, Japan
4
Faculty of Engineering Geology and Mines, Jowzjan University, Sheberghan 1901, Afghanistan
*
Authors to whom correspondence should be addressed.
Nitrogen 2025, 6(2), 40; https://doi.org/10.3390/nitrogen6020040
Submission received: 10 March 2025 / Revised: 16 May 2025 / Accepted: 22 May 2025 / Published: 29 May 2025

Abstract

The increased frequency of extreme heat stress events due to climate change is adversely impacting rice yield. Nitrogen (N) is an essential element in the synthesis of chlorophyll in rice, contributing substantially to the achievement of spikelet fertility and addressing the high yields. Two experiments were conducted in Japan and Afghanistan in 2020 and 2022, respectively, utilizing IR64 and Nipponbare (NPB) varieties to elucidate the efficacy of N top-dressing on spikelet fertility and yield of rice under heat stress conditions. In experiment I, the treatments involved were based on N application before panicle emergence in pots, including (1) control (fertilized at the tillering stage), (2) control + N topdressing, (3) heat stress (fertilized at the tillering stage), and (4) heat stress + N topdressing. Experiment II consisted of (1) control (basal dressing at the tillering stage) and (2) control + N topdressing, which was conducted under field conditions. Results showed that N application significantly (p < 0.05) increased SPAD values and spikelet fertility rates in both experiments. A positive correlation (range; r = 0.83–0.98) was observed between enhanced SPAD values and spikelet fertility rates in IR64 and NPB rice varieties under both ambient and heat stress conditions. Moreover, there were notable increases in photosynthetic rate (7.4% to 52.6%) and leaf transpiration. N top dressing significantly (p < 0.05) increased the panicle length, panicle weight, number of secondary branches/panicle, filled grain/panicle, total spikelets/panicle, and yield/plant. However, there was no significant difference in the number of primary branches per panicle and 1000-grain weight. In addition, the number of unfilled grains/panicle decreased from 5.5 to 49.7% with N top dressing in both experiments. Applying N as a top dressing improved the spikelet fertility percentage and other yield components, resulting in a high yield/plant.
Keywords: heat stress; nitrogen; SPAD value; spikelet fertility rate; rice heat stress; nitrogen; SPAD value; spikelet fertility rate; rice

Share and Cite

MDPI and ACS Style

Aryan, S.; Gulab, G.; Habibi, S.; Zahid, T.; Safi, Z.; Habibi, N.; Mahmoodzada, A.B.; Amin, M.W.; Samsor, I.A.; Erie, K. Optimizing Rice Yield and Heat Stress Resilience Through Nitrogen Top Dressing Before Panicle Emergence. Nitrogen 2025, 6, 40. https://doi.org/10.3390/nitrogen6020040

AMA Style

Aryan S, Gulab G, Habibi S, Zahid T, Safi Z, Habibi N, Mahmoodzada AB, Amin MW, Samsor IA, Erie K. Optimizing Rice Yield and Heat Stress Resilience Through Nitrogen Top Dressing Before Panicle Emergence. Nitrogen. 2025; 6(2):40. https://doi.org/10.3390/nitrogen6020040

Chicago/Turabian Style

Aryan, Shafiqullah, Gulbuddin Gulab, Safiullah Habibi, Tayebullah Zahid, Zabihullah Safi, Nasratullah Habibi, Abdul Basir Mahmoodzada, Mohammad Wasif Amin, Ijaz Ahmad Samsor, and Kenji Erie. 2025. "Optimizing Rice Yield and Heat Stress Resilience Through Nitrogen Top Dressing Before Panicle Emergence" Nitrogen 6, no. 2: 40. https://doi.org/10.3390/nitrogen6020040

APA Style

Aryan, S., Gulab, G., Habibi, S., Zahid, T., Safi, Z., Habibi, N., Mahmoodzada, A. B., Amin, M. W., Samsor, I. A., & Erie, K. (2025). Optimizing Rice Yield and Heat Stress Resilience Through Nitrogen Top Dressing Before Panicle Emergence. Nitrogen, 6(2), 40. https://doi.org/10.3390/nitrogen6020040

Article Metrics

Back to TopTop