Ammonium Retention in Sand Amended with Clinoptilolite1
- G. A. Ferguson and
- I. L. Pepper2
Clinoptilolite zeolite has a rigid three-dimensional lattice with 10−9 m sized tunnels, and an affinity for NH+4 on its internal exchange sites. These internal tunnels are too small for 10−6 m size microbes to access; hence, clinoptilolite has the potential to physically protect NH+4 from nitrification by microbes, and may reduce volatilization losses. The objective of this study was to evaluate NH+4 retention of sand amended with clinoptilolite. Retention of NH+4 on clinoptilolite amended sands incubated at 20% volumetric water content, was studied in the laboratory. Treatments were washed mortar sand amended with 0, 5, and 10% clinoptilolite by volume and 2.38 and 3.57 moles of NH+4 m−3 of soil. Retention was evaluated by monitoring NH+4 loss from the soil mix. Loss of NH+4 decreased with increasing clinoptilolite amendment. Losses also decreased when the amount of NH+4 initially applied was decreased. The effect of clinoptilolite in retaining NH+4 was more pronounced when the amount of NH+4 initially applied was increased. Clinoptilolite reduced NH+4 losses from the soil mix and would allow increased plant N fertilizer-use efficiency. Thus clinoptilolite-amended sands have potential as a growth medium for turfgrasses on golf greens, where N use efficiency is typically low.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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