The Effect of Leonardite-Derived Amendments on Soil Microbiome Structure and Potato Yield

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. The results demonstrated that the LHA treatments had a significant effect on increasing potato growth (54.9%) and tuber yield (66.4%) when compared to the control. The findings highlight the importance of amending leonardite-based humic products for maintaining the biogeochemical stability of soils, for keeping their healthy microbial community structure, and for increasing the agronomic productivity of potato plants.

Holistic Assessment of Biochar and Brown Coal Waste as Organic Amendments in Sustainable Environmental and Agricultural Applications

“…Similar to our results, there are other welldocumented reports of improved yields of a range of crops from typical application rates (10-40 t ha -1 ) of FYM, BCW and BIO (Shakoor et al 2015;Eprikashvili et al 2016;Faloye et al 2017;Akimbekov et al 2020), although some have reported remote or negative yield responses (Diacono and Montemurro 2011;Tahir et al 2011;Jeffery et al 2017;Chen et al 2018;Kováčik et al 2016). From a range of crops grown in acidic soils, it was reported that biochar amendment led to a median yield increase of 20% (Jeffery et al 2017), while compost amendment resulted in maximum yield increases of 13.6%, and thus the mean increases in yields of maize, potato and barley from FYM (32.7%), BCW (33.5%) and BIO (21.8%) amendments in this study compare well.…”

Novel Effects of Leonardite-Based Applications on Sugar Beet

“…that we found as constituents of the core seed microbiome. Microbiome changes following leonardite treatment have already been studied in other plants, such as grapevine and potato ( Cappelletti et al, 2016 ; Akimbekov et al, 2020 ). Also, Moreno et al (2017) observed an increase of Gram-negative bacteria, such as Proteobacteria , as a consequence of the application of leonardite in barley.…”

Effects of soil amendments on leaf anatomical characteristics of marigolds cultivated in cadmium-spiked soils

“…Substantial OM contents were measured in the Cd-Leo and Com-Ctrl treatments (10.2% and 11.7%, respectively), whereas lowest OM content was in the Cd-Alon treatment (3.4%). Humic substances originating from organic matter in leonardite can improve the physicochemical properties of soil and stimulate plant growth performance 19 . Rehman et al 20 indicated that increased OM content in amendments, applied in different combinations, could increase rice growth when high Cd-contaminated effluent water is applied to soil during planting.…”