The prospection of N organic sources for the controlled release fertilizers production

Abstract

Food demand from populations that should reach 9 billion tons worldwide until 2050, raising the challenge to increase agricultural production. The development of new technologies to increase food production levels to meet demands for the next decades is essential. In this context, fertilizers use efficiency (FUE) emerges as an important tool in which nutrients such as nitrogen, phosphorus and potassium are available in a gradual and synchronized way to satisfy nutrient demand of crops. However, FUE have mostly urea as an N source causing the disadvantageous action of urease that promotes volatilization losses or rapid availability of nutrients resulting in a mismatch between supply and plant needs. An alternative to the use of urea as an N source is the use of organic compounds such as castor bean and soybean, blood and animal manures, or industrial sources such as polyureas, (e.g.: urea-formaldehyde, melamine) that are mineralized in the soil due to microbial action and supply N in the form of ammonium or nitrate. This supply reaches the highest values 10-80 days, varying with the chemical composition of the material. The combination of readily available sources such as urea, and organic materials slower release (mineralization) presents as an interesting alternative for the production of FUE, however, identifying and finding sources with varying rates of mineralization are essential to establish the mix ratios and assess the effectiveness to provide nutrients. This study aims to identify the mineralization rate of different N sources and produce a fertilizer that provides enhanced efficiency of the nutrient in a spaced temporal way and hopefully synchronized to the culture.