Tuesday, November 14, 2006

Zeolite Soil Amendment to Increase Nitrogen Fertilizer Efficiency Sand-based Root Zone Mixes.

Jorge Hernandez and Getie Yilma. S. Illinois Univ. Mail Code 4415, Dept of Plant & Soil Science, Dept of Plant & Soil Science, Carbondale, IL 62901-4415, United States of America

Water pollution via the leaching of nitrogen fertilizers is becoming a significant concern in urban areas.  Golf courses may have a potential to increase N input. Establishment and maintenance of high quality turf system requires intensive application of nutrients, especially Nitrogen (N).  Sand-based root zones are specified for golf course putting greens because they resist compaction and maintain drainage under heavy traffic. However, they have low nutrient retention ability. Fertilizers such nitrate base and urea (U) are highly susceptible to leaching.  We hypothesized that the combination of clinoptilolite zeolite (CIZ) and slow release N fertilizers would increase the N efficiency in this area. Root zone mixtes were amended with 3%, 6% and 12% (W/W) CIZ, then 400 mg N/kg-1of N was applied and incubated for 90 days (24±1 ºC ). Samples were extracted 5, 15, 30, 45, 60, 90 days and analyzed for NH4+ and NO3--N (2M KCl).  The experimental design was a completely randomized design with three factors: arrangement of root zone mixes, levels of CIZ amendments, and types of fertilizers.  Another leaching experiment was also set up using leaching columns.  A local sand-based root zone mix was amended with 3 levels (0%, 6% and 12%, W/W) of CIZ and packed into leaching columns. Then 400 mg N /kg-1 as U and MU were applied.  All treatments including control units were kept at field capacity for 6 weeks.  Afterwards, each week, 0.01M KCl was added to columns until 100mL of leachate was collected.  The leachate was measured for NO3N.  The incubation study analysis showed that NH4+- N retention ability of the 12%, w/w CIZ amended root mixes was increased.  All mixes with MU are also shown a better NH4+- N retention ability than those of with U.