The use of clinoptilolite as carrier of nitrogened fertilizer with controlled release

Nitrogen fertilizers are widely used in agriculture and urea fertilizer due to their high content of nitrogen. However, their high losses, which are mainly associated with the ammonia volatilization, make it necessary the study and developmentof technologies that reduce these effects. The goal in this study was to produce new formulations based on urea fertilizer and natural zeolite clinoptilolite with tablet formulation evaluating their physical and chemical properties, as well as nitrogen losses by ammonia volatilization. The high cationic exchange capacity and the possibility of interaction with ammonia ions were the reasons to study clinoptilolite as urea carrier. The fertilizers formulations were produced with pellets with, 7 mm of diameter and 4 mm thickness, varying their carrier content urea from 1:4, 1:8 and 1:16, besides a pellet containing only grinded urea, mixed with the additives used in all samples (talc, polyvinylpyrrolidone solution and magnesium stearate) were denominated Z1U4, Z1U8, Z1U16 and tablet urea, respectively. The fertilizers were characterized by their chemical composition and morphology using techniques of XRD, FTIR, N-2 adsorption, TPD-NH3, TG and SEM/DSC. To evaluate the nitrogen losses from ammonia volatilization, it was carried out an experiment in a greenhouse with superficial application of the fertilizers on the soil The doses ranged between 100 and 200 kg N ha(-1). For the losses quantification, a Semi-Open Static Free System (SALE) was used. The characterization shows that there were no chemical interactions among the components of the formulation and changes in the composition of clinoptilolite and urea fiertilizer. Even so, the formulations was able to decrease the amount of ammonia volatilized., For the sample Z1U16, it was showed a reduction of 53% when compared with the pure urea.