Release Kinetics and Plant Availability of Potassium in Soils of Eastern India

• Published in: Communications in Soil Science and Plant Analysis Vol. 55; no. 16; pp. 2367 - 2378
• Main Authors: Zhimo, Alika N., Pal, S. K., Saha, S.
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 07.09.2024; Taylor & Francis Ltd
• Subjects: Alfisols; Bioavailability; Biomass; Boron; Entisols; Fertilizers; Inceptisols; Incubation; Incubation period; K release kinetics; Kinetics; Lolium perenne; Mathematics; Plant extracts; Potassium; ryegrass; Sodium; sodium tetraphenylboron; Soil; Soils; India
• ISSN: 0010-3624; 1532-2416; 1532-4133
• DOI: 10.1080/00103624.2024.2359576

The present experiment was undertaken to characterize the K releasing pattern as well as the bioavailability of K in nine soils under three dominant soil orders of eastern India. Soils were extracted with 0.2 M sodium tetraphenyl boron (NaTPB) and perennial ryegrass (Lolium perenne L.) was grown repeatedly with and without the addition of K fertilizer to study the K release kinetics and bioavailability. The highest K release by 0.2 M NaTPB at 144 h incubation was recorded in Entisols, while the least in Alfisols. Cumulative K released was mathematically best described by a parabolic diffusion equation and the empirical constants up to a 2 h incubation period was significantly related to relative biomass yield and K uptake by ryegrass. Considering relative biomass yield and K uptake as indices of plant K availability, the sequence of K supplying capacity of the soils under different orders was: Entisols>Inceptisols>Alfisols. The K-release rate of 30.8 mg kg-1 h-1 and the ryegrass leaf K concentration of 32.1 g kg-1 were found to be critical for this experiment. Based on the critical K release rate, the maximum amount of K released for plant uptake before showing any K deficiency symptom ranged from 179.3 mg kg-1 to 596 mg kg-1 for soils under the order Entisols, 247.9 mg kg-1 to 687.84 mg kg-1 for soils under Inceptisols and 118.67 mg kg-1 to 184.25 mg kg-1 for soils under Alfisols.