Lin Zhang, Caibin Li, Yangxi Liu
Jun 15, 2021
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Influential Citations
7
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Journal
Agriculture, Ecosystems & Environment
Abstract
Abstract Over use of nitrogen (N) fertilizers, most commonly as urea, is a major source for severe environmental impacts in agricultural field. Application of biochar-based N fertilisers is a promising strategy to enhance N retention and use efficiency (NUE) of crops, and alleviate environmental impact. In this study, granular biochar-urea fertilisers were prepared through adsorbed urea on biochar pellets. Low-rate biochar-enriched N fertiliser (BN), straw-powders-coated BN fertiliser (BNM), straw-powders-blended N fertiliser (MN), and a conventional N fertiliser were applied to tobacco root-zone soils in two fields at Linquan and Heishi, China. The 15N isotopic trace technique was used to track the applied N among soil N pools and tobacco plant organs. BN treatment increased the middle leaf yield by 43% and 14% in Linquan and Heishi, respectively. The yield increased by 28% and 39% when BNM was used compared to that of the soils were applied with N fertiliser. The addition of BN fertiliser decreased the NUE of tobacco but increased root-zone liable N (KEN) retention at the time of harvest, leading to a 3–10% increase in soil KEN accumulation. Such an effect could be enhanced by straw powder coating in Heishi, mainly to increase supplied urea-N retention in the root-zone. 15N fertiliser tracing revealed that application of small amounts of granular biochar-based N fertilisers increased the uptake of intrinsic soil N by plants compared to that with only N fertiliser application. Thus, biochar could be blending with urea to obtain granular biochar-based N fertilisers to replace mineral urea, thereby reducing N application rate. Further studies at multiple sites are required to determine the effects of biochar plus urea on N processes in soil–plant systems.