Impact of Soil Organic Bioregeneration Amendments on Maize Biomass and Soil Physical Quality

Combining inorganic and organic soil amendments with mineral fertilizers is promising for soil quality enhancement in modern agronomy systems. In this research, four main organic components were used in fertilizer formulations: coconut coir, biochar, lignite, and leonardite (enriched with microelements, tryptophan, and bacterial metabolic products). The treatments were assigned to the completely randomized design with a control object, without any soil amendments, and with only mineral fertilization. Aboveground biomass and root characteristics of maize (root length density, mean root diameter, root surface area density, specific root length, root volume density, and root dry matter) and water retention and characteristics of soil pores were determined. Compared to the control, all fertilizer formulations applied deteriorated the water retention properties of the soil. The highest plant available water content value was obtained for the control without any fertilizers. The addition of organic fertilizer formulations consisting of coconut coir, biochar, lignite, leonardite, microelements, tryptophan, and metabolic products of Pseudomonas sp. and Bacillus subtilis did not play a significant role in improving soil physical characteristics. The lowest productivity was characterized for maize without any fertilizers and amendments. All soil organic amendments resulted in lower yields than the one with only mineral fertilization. The highest root dry matter was obtained when lignite and leonardite were used as main components. Organic amendments can be recommended for soil bioregeneration, but their main effect on maize productivity is attributed to the mineral component.