Sandy soils have lowwater and nutrient retention capabilities so that zeolite soil amendments are used for highvalue land uses including turf and horticulture to reduce leaching losses of NH4+ fertilisers. MesoLite is a zeoliticmaterial made by caustic treatment of kaolin at 80–95 °C. It has a moderately low surface area (9–12 m2/g) andvery high cation exchange capacity (494 cmol(+)/kg). Laboratory column experiments showed that anaddition of 0.4% MesoLite to a sandy soil greatly (90%) reduced leaching of added NH4+ compared to anunamended soil and MesoLite is 11 times more efficient in retaining NH4+ than natural zeolite. Furthermore,NH4-MesoLite slowly releases NH4+ to soil solution and is likely to be an effective slow release fertiliser.© 2009 Elsevier B.V. All rights reserved.