The dependence of cocksfoot productivity of liming and nitrogen application and the assessment of qualitative parameters and environmental impact using biomass for biofuels

Abstract

In order to evaluate the liming and nitrogen efficiency of cocksfoot (Dactylisglomerata L.) productivity, a field experiment was performed in Western Lithuania's naturally acidic Retisol area (55?43' N, 21?27' E). Based on seven years of research data, dry mass (DM) yield (including first and second cuttings) reliably varied depending on the growing year, from 4.57 to 7.34 t ha-1. The most significant and positive impact on DM yield was obtained by the application of higher liming (6.0 t ha-1 CaCO3) and nitrogen (120 kg ha-1) rates. Liming utilization efficiency (LUE) was affected by the year of growth (although not always significantly), with a 6.0 t ha-1 CaCO3 liming rate and nitrogen fertilization. Nitrogen utilization efficiency (NUE) varied depending on the growing year and N fertilization rate. One of the most effective solutions for improving cocksfoot biomass is to prepare pressed granulated biofuel, which is potentially a good quality raw material for the direct combustion process. The execution and evaluation of technological parameters and properties of produced pellets revealed that cocksfoot pellet humidity reached 10.0% ± 0.6%, whereas pellet density was sufficiently high, and reached 983.8 ± 22.9 kgm-3 DM. The lower calorific value of cocksfoot pellets reached 17.7 MJkg-1. Ash content after pellet burning was relatively high, reaching 7.0-7.6%. Pellet ash melting temperatures were sufficiently high, with ash softening temperature (ST) reaching 1065 ?C. Determined emissions of harmful gases from the burning of cocksfoot pellets (CO2, CO, SO2, NOx and unburnt hydrocarbons CxHy) did not exceed the permissible limits.