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Effectiveness of recovered magnesium phosphates as fertilizers in neutral and slightly alkaline soils

Massey, M.S. and Davis, J.G. and Ippolito, J.A. and Sheffield, R.E. (2009) Effectiveness of recovered magnesium phosphates as fertilizers in neutral and slightly alkaline soils. Agronomy Journal. 101(2):323-329.

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Magnesium phosphates such as struvite (MgNH4PO4 · 6H2O) can be recovered from municipal, industrial, and agricultural
wastewaters. However, limited information is available on the beneficial reuse of these recovered products; research has focused
on low pH soils. Th is study determined whether recovered struvite and dittmarite (MgNH4PO4 · H2O) were effective P fertilizers
in neutral to slightly alkaline soils. In addition to commercially available triple superphosphate (TSP) and certified organic
rock phosphate (RP), recovered struvite, dittmarite, and a heterogeneous recovered phosphate were evaluated in a laboratory
dissolution study and as fertilizers for spring wheat (Triticum aestivum L.) in a greenhouse study. Struvite and dittmarite were
much more soluble than RP, but less soluble than TSP. Laboratory dissolution kinetics were fast, with most materials nearing
equilibrium within 7 to 14 d. At a soil pH of 6.5, both dittmarite and struvite increased the average plant P concentration over the
control. Struvite and dittmarite performance was similar to TSP. There were no significant differences in plant dry matter (DM)
production or total P uptake at pH 6.5. In the limed soil (pH 7.6), many treatments had plant P concentrations significantly lower
than the control, but most fertilizers increased DM production over the control; all fertilizers generally performed similarly to
one another. These findings support previous work showing recovered Mg phosphates to be effective in acidic soils, and provide
evidence that they are also effective in slightly alkaline soils. Recovered Mg phosphates could become a useful alternative for P
fertilization in arid and semiarid environments.

Item Type: Article
NWISRL Publication Number: 1285
Subjects: Soil > Fertility
Soil > Chemistry
Depositing User: Users 6 not found.
Date Deposited: 17 Apr 2009 14:57
Last Modified: 18 Oct 2016 15:15
Item ID: 1309