agriculture Article The Effect of Leonardite-Derived Amendments on Soil Microbiome Structure and Potato Yield Nuraly Akimbekov 1,*, Xiaohui Qiao 1, Ilya Digel 2 , Gulzhamal Abdieva 1, Perizat Ualieva 1 and Azhar Zhubanova 1 1 Department of Biotechnology, Al-Farabi Kazakh National University, al-Farabi ave. 71, 050040 Almaty, Kazakhstan;
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[email protected] Received: 27 March 2020; Accepted: 29 April 2020; Published: 1 May 2020 Abstract: Humic substances originating from various organic matters can ameliorate soil properties, stimulate plant growth, and improve nutrient uptake. Due to the low calorific heating value, leonardite is rather unsuitable as fuel. However, it may serve as a potential source of humic substances. This study was aimed at characterizing the leonardite-based soil amendments and examining the effect of their application on the soil microbial community, as well as on potato growth and tuber yield. A high yield (71.1%) of humic acid (LHA) from leonardite has been demonstrated. Parental leonardite (PL) and LHA were applied to soil prior to potato cultivation. The 16S rRNA sequencing of soil samples revealed distinct relationships between microbial community composition and the application of leonardite-based soil amendments. Potato tubers were planted in pots in greenhouse conditions. The tubers were harvested at the mature stage for the determination of growth and yield parameters.