Improving Soil Functions by Zeolitic Amendments in Agricultural Lands

Over the years, natural zeolites are expected to find promising applications in agriculture given their unique nano-porous structure, capability of adsorption, cation exchange as well as molecular sieving and eco-friendly nature for sustainable agriculture. These make them attractive for a variety of potential applications including use as soil conditioners, nutrient retainers, slow-release fertilizers (N-P-K), zeoponic plant-growth substrates, carriers for pesticides and remediants in contaminated soils. Besides, synthesis of high performance multifunctional zeolites or modification of existing zeolites to obtain superior properties are recently under investigation. It is difficult to evaluate the performance of a particular application of a zeolite. This is because there are many factors that control its performance. Moreover, type of soil is a key factor in determining the effectiveness of zeolitic amendments to restore soil functions. Therefore, future works will need to address a number of questions with the use of zeolites in soils. Most benefits of soil-applied zeolite have been reported in course-textured acid or highly weathered soils. The addition of natural zeolites to soils increases both CEC and pH, of which the latter is not suitable for alkaline soils. For this, protonic zeolites may be good candidates for election. However, they should be fully characterized and tested before it can be used reliably. Eventually, very little (if any) is known about the long-term impact of zeolites on soil microbial community, which merits much more investigation in the future.