Foliar Spraying of Potassium Nitrate, Salicylic Acid, and Thio-urea Effects on Growth, Physiological Processes, and Yield of Sodicity-Stressed Paddy (Oryza sativa L.) with Alkali Water Irrigation

• Published in: Journal of plant growth regulation 2022-07, Vol.41 (5), p.1989-1998
• Main Authors: Singh, Awtar, Bali, Aradhana, Kumar, Ashwani, Yadav, Rajender Kumar, Minhas, Paramjit Singh
• Format: Article
• Language: English
• Subjects: Agriculture; Alkalinity; Biomedical and Life Sciences; Crop yield; Foliar applications; Grain; Groundwater; Groundwater irrigation; Growth regulators; Gypsum; Irrigation; Irrigation water; Life Sciences; Lysimeters; Moisture content; Photosynthesis; Physiological effects; Physiology; Plant Anatomy/Development; Plant growth; Plant Physiology; Plant Sciences; Potassium; Potassium nitrate; Receiving waters; Response functions; Salicylic acid; Sodium; Sodium carbonate; Spraying; Sulfuric acid; Urea; Water content
• ISSN: 0721-7595; 1435-8107
• DOI: 10.1007/s00344-022-10575-8

Exogenous applications of plant growth regulators (PGRs) were evaluated for their effects on growth, physiological attributes, and yield of sodicity stressed paddy during 2018 and 2019. Crop was grown in fixed lysimeters enduring sodicity stress due to long-term irrigation with two types of alkali waters having residual sodium carbonate [RSC (AW 1 : 5 and AW 2 : 10 me/L)], and latter (AW 2 ) ameliorated to neutralize RSC equivalent to 5 me/L with either sulfuric acid or gypsum. Consequent losses in paddy yield with different alkalinity water irrigation ranged between 17–48% and 34–100% during 2018 and 2019, respectively. Each plot, receiving different alkalinity water irrigation, was further divided into four equal parts for evaluation of PGRs. PGRs included thio-urea (TU, 500 ppm), potassium nitrate (PN, 15 g/L), and combinations of TU + PN during 2018 while latter was replaced with salicylic acid (SA, 10 µM) in 2019. PGRs were sprayed four times, i.e., at tillering, maximum growth, panicle initiation to grain formation, and two days after 3rd spray. The increase in grain yield was equal to 14, 12, and 12% with TU, PN, and TU + PN during 2018 and 5–14% during 2019. PGRs triggered physiological attributes like photosynthetic rate, SPAD values, proline, membrane injury, malondialdehyde, and relative water content. Maas and Hoffman-type response functions showed that, at exchangeable sodium percentage (%) 30, the relative yields were 0.59, 0.53, and 0.49 under TU, PN, and control (No PGR), respectively. These results signify the agronomic usefulness of foliar spray of PGRs in improving paddy yield in the alkali groundwater irrigation-induced sodicity stress areas. Graphical Abstract