Ts. Perrin et al., DECREASING NITROGEN LEACHING FROM SANDY SOIL WITH AMMONIUM-LOADED CLINOPTILOLITE, Journal of environmental quality, 27(3), 1998, pp. 656-663
Nitrogen (N) loss from irrigated cropland, particularly sandy soils, s
ignificantly contributes to nitrate (NO3-) levels in surface and groun
dwaters, In this study, as a preface to a plant growth study, we compa
red N leaching from NH4+-loaded clinoptitolite (A-Cp) and (NH4)(2)SO4
(AS) in two media: a rounded quartz sand and a sandy soil. We hypothes
ized that quartz sand or soil amended with A-Cp would leach significan
tly less N than these media amended with AS, and that more N would lea
ch from smaller A-CD size fractions than front larger A-Cp size fracti
ons. Ammonium sulfate, or one of the three A-CI, size fractions, small
(<0.25 mm), medium (0.25-2 mm), or large (2-4 mm), was banded at a de
pth of 5 cm in leaching columns filled with inert quartz sand at a rat
e of 112, 224, or 336 kg N ha(-1). The experiment was repeated with sa
ndy soil in greenhouse pots at rates of 112 and 224 kg N ha(-1). The c
olumns and Dots were leached for about 40 d with a simulated irrigatio
n water. Significantly more N, as NH4+ and NO3-, leached from AS amend
ments than any of the A-Cp amendments in both experiments. Results ind
icated that the larger the A-Cp size fraction, the slower NH4+ is rele
ased from A-Cp. Ammonium-Cp slowly releases N and could significantly
minimize N leaching from sandy soils compared to AS.