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.

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
PublisherElsevier France-Editions Scientifiques Medicales Elsevier

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