Ts. Perrin et al., AMMONIUM-LOADED CLINOPTILOLITE - A SLOW-RELEASE NITROGEN-FERTILIZER FOR SWEET CORN, Journal of plant nutrition, 21(3), 1998, pp. 515-530
Nitrogen(N) loss from irrigated cropland, particularly sandy soils, si
gnificantly contributes to nitrate (NO3-) contamination in surface and
ground waters and increases N applications to crops. Ammonium-loaded
clinoptilolite (A-Cp) may reduce N leaching from sandy soils while sus
taining plant productivity. We conducted Mo greenhouse plant growth ex
periments with sweet corn (Zea mays L.). Pots containing a sandy soil
planted with sweet corn were fertilized with either ammonium sulfate (
AS) or one of three size fractions of A-Cp, small (<0.25 mm), medium (
0.25 to 2 mm), or large (2 to 4 mm), at rates of 112, 224, or 336 kg N
ha(-1) (Experiment #1) and 112 or 224 kg N ha(-1) (Experiment #2). We
compared ammonium (NH4+) and NO3- leaching from these pots and compar
ed corn relative growth rates (RGR), leaf area ratio (LAR), and net as
similation rate (NAR) among all N fertilizers. Soil amended with AS le
ached 10 to 73% of the added N, depending on N rate, whereas <5% of th
e added N leached from the A-Cp amended soil regardless of N rate and
Cp particle size. No differences in corn growth were observed among N
fertilizers, however, plants fertilized with A-Cp assimilated signific
antly more N than AS fertilized plants. Results indicate fertilization
with A-Cp will minimize N leaching from sandy soils while sustaining
normal corn growth.