Ammonia volatilization from an encapsulated urea enriched biochar under different soil salinity stresses

Abstract

Apart from nitrogen fertilizer management, improving nitrogen fertilizer formulations is known as a promising strategy for improving nitrogen uptake efficiency. The present study was aimed to synthetize a nitrogenous fertilizer with low ammonia volatilization potential. Pruning wastes of mature pistachio trees were converted to biochar, enriched with urea, and encapsulated with five different biodegradable polymer and solution compounds, namely Fert.1, Fert.2, Fert.3, Fert.4 and Fert.5. Our objective was to investigate the ammonia volatilization potential of these five products compared to urea in two soils with distinct electrical conductivities of 5.3 and 13.79 dS m⁻¹. The results showed that total volatilized nitrogen from soil with electrical conductivity of 5.3 dS m⁻¹ was 85%, 80%, 72%, 66%, 36% and 50% of applied nitrogen for urea, Fert.1, Fert.2, Fert.3, Fert.4, and Fert.5, respectively. While total volatilized nitrogen from urea, Fert.1, Fert.2, and Fert.3 was not impacted by increased soil salinity, it significantly increased by 49% and decreased by 22% for Fert.4 and Fert.5, respectively. Hence, Fert.4 and Fert.5 with 57% and 52% reduction in total volatilized ammonia compared to urea are recommended for non-saline and saline conditions, respectively. Overall, it can be concluded that encapsulation of nitrogen fertilizer can decrease ammonia volatilization potential by up to 50%.