Impact of Source and Method of Potassium Application on Dry Matter Accumulation and Partitioning of Potassium in Rice (Oryza sativa L.)

The experiment was carried out to assess dry matter accumulation and potassium partitioning in submerged rice upon application of three organic potassium salts, viz., potassium citrate (KC), potassium gluconate (KG), and potassium humate (KH), and inorganic salt, potassium sulfate (KS). Treatments included recommended dose of potassium (RDF-K, 60 kg ha−1) via foliar or soil application of KS, alone or in combination with foliar application of three organic potassium salts (KC, KG, and KH), in three split doses at three rice phenological stages, viz., tillering, panicle initiation, and early flowering. Solely foliar application of organic K salts resulted in 76% K uptake in rice straw compared with 13% K uptake in grain, which diminished internal use efficiency (IUE) and partial factor productivity (PFP) of K. Conjoint application of KS (half of RDF-K as soil application) and KH (half of RDF-K as foliar spraying) obtained highest grain K accumulation and significantly enhanced IUE and PFP of K. KH performed best among the different K salts used and significantly enhanced root dry matter which resulted in significantly highest grain N and P uptake. This study confirmed that organic salts of K altered dry matter and K partitioning, and soil application of KS (half of RDF-K) in combination with foliar application of KH (half of RDF-K) at three growth stages elevated K utilization efficiency of submerged rice.