*Article* **Influence of Fertilization and Rootstocks in the Biomass Energy Characterization of** *Prunus dulcis* **(Miller)**

### **Alba Mondragón-Valero 1, Borja Velázquez-Martí 2,\*, Domingo M. Salazar 1 and Isabel <sup>L</sup>ópez-Cortés 1**


Received: 16 March 2018; Accepted: 3 May 2018; Published: 8 May 2018

**Abstract:** The importance of replacing fossil fuels with new energy routes such as the use of biomass leads to the improvement of sources such as agricultural and forest systems through adequate managemen<sup>t</sup> techniques.The selection of the vegetal material and the managemen<sup>t</sup> practices can influence the properties and quality of the obtained biofuel. The properties of the biomass obtained from pruning almond trees (*Prunus dulcis* (Mill)) have been analyzed in this study. Two varieties were tested, Marcona and Vayro, with three rootstocks, GF305, GF677 and GN Garnem, under different fertilization systems. The quality of the biofuel was evaluated with respect to the chemical composition and gross calorific value. We observed that the variables that mostly influenced the gross calorific value of the biomass were the variety, the rootstock and, primarily, the variety-rootstock interaction. Marcona presented better biomass properties than Vayro. Trees grafted on GF305 obtained a higher gross calorific value than the ones grafted on GF677 and GN Garnem. The percentage of nitrogen highly depended on the fertilization treatment applied, with saccharides and aminoacid fertilization accumulating a higher level of nitrogen than the humic and fluvic fertilization.

**Keywords:** biomass; variety and rootstock selection; almond tree; agricultural practices
