Lignite Scaffolding as Slow-Release N-Fertilizer Extended the SN Retention and Inhibited N Losses in Alkaline Calcareous Soils

Abstract

Conventional nitrogen (N) fertilizers particularly urea mineralized quickly in soil. Without sufficient plant uptake, this rapid mineralization favors the heavy N losses. Lignite is a naturally abundant and cost-effective adsorbent capable of extending multiple benefits as a soil amendment. Therefore, it was hypothesized that lignite as an N carrier for the synthesis of lignite-based slow-release N fertilizer (LSRNF) could offer an eco-friendly and affordable option to resolve the limitations of existing N fertilizer formulations. The LSRNF was developed by impregnating urea on deashed lignite and pelletized by a mixture of polyvinyl alcohol and starch as a binder. The results indicated that LSRNF significantly delayed the N mineralization and extended its release to >70 days. The surface morphology and physicochemical properties of LSRNF confirmed the sorption of urea on lignite. The study demonstrated that LSRNF also significantly decreased the NH3-volatilization up to 44.55%, NO3-leaching up to 57.01%, and N2O-emission up to 52.18% compared to conventional urea. So, this study proved that lignite is a suitable material to formulate new slow-release fertilizers, suiting to alkaline calcareous soils favorably where N losses are further higher compared to non-calcareous soils.

Preparation and NH4+ Adsorption Performance of Ultrafine Lignite-Based Porous Materials

“…Lignite, owing to its well-developed porous structure, possesses a relatively high specific surface area and exhibits a non-uniform pore size distribution [18,19]. It is characterized by a significant content of humic and fulvic acids, along with an abundance of oxygen-containing functional groups that serve as binding sites [20,21]. These superior properties endow lignite with excellent adsorptive capacity, establishing it as a natural adsorbent material.…”

Assessing the Impact of Lignite-Based Rekulter Fertilizer on Soil Sustainability: A Comprehensive Field Study

“…The literature suggests that organic amendments, including lignite-based fertilizers, can influence soil pH [10], organic carbon content [11], nutrient availability [12,13], and microbial activity [14]. These amendments have been shown to enhance soil fertility [15], improve crop yields [16], and promote sustainable agricultural practices [17]. Lignite-based fertilizers, such as Rekulter [8], have gained attention as potential soil amendments due to their organic content and nutrient-rich composition [18].…”