Shivashankar K, Potdar M P, Gawdiya Sandeep, Golshetti Aishwarya, Kanade Aditya Kamalakar, Balol Gurupada, Biradar D P, Math K K, Al-Ansari Nadhir, El-Hendawy Salah, Mattar Mohamed A, Salem Ali
Department of Agronomy, College of Agriculture, UAS, Dharwad, 580005, India.
School of Agriculture, Galgotias University, Greater Noida, Uttar Pradesh, 203201, India.
Sci Rep. 2025 Jul 2;15(1):22842. doi: 10.1038/s41598-025-05255-y.
Real-time monitoring of canopy chlorophyll content is crucial for understanding crop growth and guiding precision agricultural management. The SPAD chlorophyll meter is a valuable tool for assessing nitrogen status in maize (Zea mays L.), a key cereal crop used for food, feed, and biofuels. Efficient nitrogen management is essential to maximize maize yield, particularly under varying water regimes. A study conducted over two years (2020-2021) utilized a strip plot design to investigate the spatiotemporal dynamics of SPAD readings and their correlation with maize yield under rainfed (M1) and irrigated (M2) conditions. Eight precision nitrogen management practices were implemented, including SPAD at sufficiency index and Green Seeker at response index, achieving ranges of 86-100% and 1.11-1.41, respectively. The findings revealed that irrigated maize produced significantly higher grain yields (6347 kg ha) compared to rainfed maize (5262 kg ha). The highest yield (9508.2 kg ha) was achieved when nitrogen was applied at a sufficiency index of 96-100%. The correlation between SPAD values and grain yield was strongest at reproductive stages (VT and R4), with R² values of 0.99 and 0.98 under rainfed conditions. In irrigated conditions, R² values ranged from 0.95 to 0.96 for earlier growth stages (V10, V12, VT, and R4). Multivariate analysis indicated critical management stages for optimizing yields in both conditions. Overall, SPAD-based nitrogen management strategies have the potential to enhance maize yields and resource efficiency while informing the development of sophisticated monitoring tools for real-time crop management.
实时监测冠层叶绿素含量对于了解作物生长和指导精准农业管理至关重要。SPAD叶绿素仪是评估玉米（Zea mays L.）氮素状况的重要工具，玉米是一种用于食品、饲料和生物燃料的关键谷类作物。高效的氮素管理对于实现玉米产量最大化至关重要，特别是在不同水分条件下。一项为期两年（2020 - 2021年）的研究采用条带试验设计，研究了雨养（M1）和灌溉（M2）条件下SPAD读数的时空动态及其与玉米产量的相关性。实施了八种精准氮素管理措施，包括充足指数下的SPAD和响应指数下的绿色寻踪仪，其范围分别为86 - 100%和1.11 - 1.41。研究结果表明，灌溉玉米的籽粒产量（6347 kg/ha）显著高于雨养玉米（5262 kg/ha）。当充足指数为96 - 100%时施氮，产量最高（9508.2 kg/ha）。在生殖阶段（VT和R4），SPAD值与籽粒产量的相关性最强，雨养条件下R²值分别为0.99和0.98。在灌溉条件下，早期生长阶段（V10、V12、VT和R4）的R²值范围为0.95至0.96。多变量分析表明了两种条件下优化产量的关键管理阶段。总体而言，基于SPAD的氮素管理策略有潜力提高玉米产量和资源利用效率，同时为开发用于实时作物管理的精密监测工具提供依据。
