Preparation of a Slow Release Biofertilizer From a Polymeric Urea-Formaldehyde Matrix (PUFM)

Fertilizers industry faces the challenge of improving the efficiency of its products either by optimizing the fertilizers in use or by developing new types of them. During the last decade, controlled and slow release technologies have become more important. These technologies aim to increase the efficiency of the applied substance by increasing its action over time and avoiding losses of all kinds (leaching, volatilization). The main purpose of the current study was to obtain a slow release biofertilizer by incorporating microalgae into a polymeric urea-formaldehyde matrix (PUFM). The quantitative analysis of macronutrients and micronutrients in the microalgae was determined using different techniques including titration, UV and Atomic Adsorption Spectroscopy. The matrix and the formulation obtained (PUFM + CHLO) were also characterized by Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The "in vitro" study showed a typical slow release behavior of nitrogen (N), phosphorus (P) and potassium (K) macronutrients. It was also shown that (PUFM + CHLO) formulation has the slowest macronutrients release time with a maximum release of 28%, 26% y 46% for (N-P-K) macronutrients respectively during a period of 30 days. The "in vivo" study exposed the benefits of the biofertilizer formulation (PUFM + CHLO) from conventional commercial fertilizer (CF) (NPK-14-5-12). Due to the presence of nutrients of natural origin in microalgae, (PUFM + CHLO) shows ecological effects which could also developing sustainable agriculture systems.