Abstract

MILLAN, Guillermo et al. Use of clinoptilolite as a carrier for nitrogen fertilizers in soils of the Pampean regions of Argentina. Cienc. Inv. Agr. [online]. 2008, vol.35, n.3, pp.293-302. ISSN 0718-1620.  http://dx.doi.org/10.4067/S0718-16202008000300007.

The properties of clinoptilolite related to cationic exchange and ionic selectivity have motivated us to study its application for agronomic purposes. The high potential of the clinoptilolite has been demonstrated as a vehicle for nitrogen fertilizers, with the aims of decreasing negative impacts on the environment and increasing fertilizer efficiency The objective of this study was to evalúate the effects of an exchanged form, clinoptilolite-NH₄, and an occluded form, clinoptilolite-urea, of nitrogen fertilizer relative to commercial urea on dry matter and the nitrogen uptake efficiency of Lolium multiflorum under controlled conditions. Lolium multiflorum, sowed in a sandy loam soil, was fertilized with 0, 60, 120, and 180 kgha'of nitrogen. Yield increased considerably and nitrogen uptake efficiency was enhanced when clinoptilolite-NH₄ was used, possibly due to its ability to retain and slowly libérate NH₄⁺ ions. This effect produces time differences in nitrogen disponibility in relation to urea, making the nitrogen available for a longer time for the plant. The clinoptilolite-urea treatments reduced yields significantly in comparison with urea applications only at the lowest dose. In addition, the nitrogen uptake efficiency was always lower than the other treatments. This behavior is related to the fact that nitrogen liberation dynamics of the occluded form are much slower than for the ionic one.

Keywords : Cation desorption; molecular occlusion; N uptake efficiency.

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