School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom.
Environmental Technology Program, School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
Environ Pollut. 2021 Jan 1;268(Pt A):115684. doi: 10.1016/j.envpol.2020.115684. Epub 2020 Sep 18.
Anaerobic digestate and biochar are by-products of the biogasification and pyrolysis of agricultural wastes. This study tested the hypothesis that combined application of anaerobic pig/cattle manure digestate and coconut husk (CH) biochar can improve soil nutrient conditions, whilst minimizing atmospheric and groundwater pollution risks. Microcosms simulated digestate application to agricultural soil with and without CH biochar. Ammonia volatilization and nutrient leaching were quantified after simulated heavy rainfalls. Archaeal and bacterial community and abundance changes in soils were quantified via next generation sequencing and qPCR of 16S rRNA genes. Nitrifying bacteria were additionally quantified by qPCR of functional genes. It was found that CH biochar retarded nitrate leaching via slower nitrification in digestate-amended soil. CH biochar reduced both nitrifying archaea and bacteria abundance in soil by 71-83 percent in the top 4 cm soil layer and 66-80 percent in the deeper soil layer one month after the digestate application. Methanotroph abundances were similarly reduced in the CH biochar amended soils. These findings demonstrate combined benefits of anaerobic digestate and CH biochar application which are relevant for the development of a more circular rural economy with waste minimization, renewable energy production, nutrient recycling and reduced water pollution from agricultural land.
厌氧消化物和生物炭是沼气和热解农业废物的副产品。本研究检验了一个假设，即联合应用厌氧猪/牛粪消化物和椰子壳（CH）生物炭可以改善土壤养分条件，同时最大限度地降低大气和地下水污染风险。微宇宙模拟了农业土壤中有无 CH 生物炭的消化物应用。在模拟大雨后，定量了氨挥发和养分淋失。通过下一代测序和 16S rRNA 基因的 qPCR 定量了土壤中细菌和细菌群落及其丰度的变化。通过功能基因的 qPCR 进一步定量了硝化细菌。结果发现，CH 生物炭通过减缓消化物添加土壤中的硝化作用来延迟硝酸盐淋失。CH 生物炭在一个月后，将土壤中硝化古菌和细菌的丰度减少了 71-83%，在 4cm 深的土壤层中减少了 66-80%。甲烷营养菌的丰度在添加 CH 生物炭的土壤中也同样减少。这些发现表明，厌氧消化物和 CH 生物炭的联合应用具有多种益处，对于发展一个更具循环性的农村经济具有重要意义，该经济可以实现废物最小化、可再生能源生产、养分回收以及减少农业用地的水污染。
