Microbial biomass P dynamics and sequential P fractionation in high and low P fixing Kenyan soils

A - Papers appearing in refereed journals

Koutika, L-S., Crews, T. E., Ayaga, G. and Brookes, P. C. 2013. Microbial biomass P dynamics and sequential P fractionation in high and low P fixing Kenyan soils. European Journal Of Soil Biology. 59 (Nov-Dec), pp. 54-59.

AuthorsKoutika, L-S., Crews, T. E., Ayaga, G. and Brookes, P. C.
Abstract

We tested how the incorporation of farmyard manure (FYM) and inorganic phosphorus (P), KH2PO4 fertilizer changed soil microbial biomass phosphorus (biomass Po and inorganic and organic P fractions) in high and low P fixing Kenyan soils. Four soil treatments were compared during 32 weeks of laboratory incubation: (i) Nil; (ii) FYM (10 g kg−1); (iii) KH2PO4 (2.5 g kg−1) (P); and (iv) FYM (10 g kg−1) + KH2PO4 (2.5 g P kg−1). Biomass P was determined by fumigation-extraction followed by resin extraction, and P availability determined using a modified Hedley P fractionation method. The addition of FYM + KH2PO4 only increased biomass P in the high P fixing soil. From a maximum of about 22.5 μg P g−1 soil (week 1), biomass P declined to 4.8 (week 2), increased steadily to week 16 (15.2), and then decreased to 9.7 μg P g−1 soil (week 32). Biomass P in the low P fixing soil, with higher fertility, resin P and organic matter concentrations did not show any significant change. The P fractions that changed the most relative to the control, were the resin, Po–HCO3 and P–OH (week 1 and 16). This difference was enhanced in the high P fixing soil but resin P was the same in that soil at week 16, and the reduction in Po–OH in the FYM + KH2PO4 treatment (162.4 μg P g−1) compared to the control (242.2 μg P g−1) was more pronounced. This indicates an enhancement of microbial activity in the high P fixing soil.

KeywordsResin P; Microbial biomass P; High P fixing soil; Low P fixing soil; Sequential P fractionation
Year of Publication2013
JournalEuropean Journal Of Soil Biology
Journal citation59 (Nov-Dec), pp. 54-59
Digital Object Identifier (DOI)doi:10.1016/j.ejsobi.2013.10.002
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDelivering Sustainable Systems (SS) [ISPG]
Optimisation of nutrients in soil-plant systems: Determining how phosphorus availability is regulated in soils
Output statusPublished
Publication dates
Online30 Oct 2013
Publication process dates
Accepted07 Oct 2013
Copyright licensePublisher copyright
ISSN1164-5563
PublisherElsevier France-Editions Scientifiques Medicales Elsevier

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