Differential responses of rice (Oryza sativa L.) to foliar fertilization of organic potassium salts

Abstract

Citric acid, gluconic acid, and humic acid are effective biostimulants and potassium salts of these organic acids are evidenced to have positive impacts in plant nutrition. This experiment aimed to compare the performances of organic potassium salts, viz. potassium citrate (C), potassium gluconate (G), and potassium humate (H) with commercially available inorganic potassium salt on submerged rice. Treatments included foliar application of three organic potassium salts (C, G, and H) and foliar or soil application of inorganic potassium sulfate (S), alone or in combination, with different doses. Foliar application of organic potassium salts resulted in enhanced plant height (1.6%), chlorophyll content (11.6%), grain yield (6.9%), and nutrient uptake (N, P, K, and S) by rice than inorganic K2SO4. Conjoint application of H (half of RDF-K as foliar spraying) and S (half of RDF-K as soil application) obtained highest straw (22.4 g/kg soil) and grain yield (5.6 g/kg soil). Moreover, potassium humate performed best among the different potassium salts used and significantly enhanced the number of leaves, root biomass, and nutrient uptake. This study confirmed the growth promoting attributes of organic potassium salts by improving yield and nutrient uptake of submerged rice. © 2020 Taylor & Francis Group, LLC.