Estimation of microbial biomass potassium in paddy field soil

Abstract

Potassium (K) in microbial cells, microbial biomass K, in soil has been recently recognized as a K pool for plant growth. We determined soil microbial biomass K in paddy fields to reveal its importance as a K pool in paddy field soil for the first time. Microbial biomass K ranged from 5 to 21 mg K kg −1 in the soil samples periodically collected from a paddy field and the value corresponded to 41% of the exchangeable K on average. Both microbial biomass K and exchangeable K increased conspicuously due to the long-term application of livestock manure compost or rice straw compost. Biomass K was higher than exchangeable K under K-deficient conditions in the long-term experimental plots without K application. The present study revealed that the microbial biomass contained considerable amounts of K in paddy field soil, indicating the need for evaluation of the microbial biomass K as a source and a stock of K in soil that has been overlooked.

Base cations in the soil bank. Non-exchangeable pools may sustain centuries of net loss to forestry and leaching

“…Calcium in known to form insoluble complexes with organic compounds such as oxalate anion, which are not salt-extractable (Dauer et al 2014), but these complexes may be available to plants and microbes over relatively short timescales. The microbial biomass of the soil is quite large, has considerably higher nutrient concentrations than bulk organic matter, and turns over very rapidly, and may thus represent a significant pool of available base cations that is missed in salt extractions (Yamashita et al, 2014, Lorenz et al 2010, van der Heijden et al 2014.…”

Base cations in the soil bank: non-exchangeable pools may sustain centuries of net loss to forestry and leaching

“…Calcium is known to form strong complexes with organic compounds such as the oxalate ion, which are poorly soluble and not salt extractable (Dauer and Perakis, 2014), but these complexes may be available to plants and microbes over relatively short timescales. The microbial biomass of the soil is quite large, has considerably higher nutrient concentrations than bulk organic matter, turns over very rapidly, and may thus represent a significant pool of available base cations that is missed in salt extractions (Yamashita et al, 2014;Lorenz et al, 2010;van der Heijden et al, 2014). Aluminum and iron oxides and hydroxides may also directly or indirectly (via organic matter or phosphate bridges) adsorb base cations (Kinniburgh et al, 1976;Grove et al, 1981).…”

“…It focuses specifically on the monitoring of physical, chemical, and biological processes in time and space to increase the knowledge on causes of ecosystem changes (Starr, 2011). Data from the Kindla catchment are used for biogeochemical process evaluations (see e.g., articles in Starr, 2011), status and trend assessments (e.g., Vuoremaa et al, 2018), and model exercises (e.g., Zetterberg et al, 2014;McGivney et al, 2019). The Kindla site is also designated as one Critical Zone Observatory, and in this article we evaluate data from Kindla soils collected and analyzed within the EU Fp7 project Soil Transformations in European Catchments (SoilTrEC, Banwart et al, 2011).…”

“…2 Bulk density was estimated for each horizon with the pedo-transfer function fromNilsson and Lundin (2006) based on depth and organic carbon content. 3 Site index according toZetterberg et al (2014).…”

Optimasi produksi kedelai (Glycine max L. Merr) melalui aplikasi pupuk hayati dan budidaya jenuh air di lahan rawa

“…Fosfor tersedia meningkat karena aktivitas bakteri Aeromonas punctata RJM 3020 dapat meningkatkan pelarutan P terfiksasi didalam tanah. Peningkatan K dapat dipertukarkan di dalam tanah mungkin dapat pula disebabkan karena perkembangan aktivitas mikroorganisme di dalam tanah (Araujo et al, 2009;Yamashita et al, 2013;Singh et al, 2010;Parmar & Sindhu, 2013).…”