Impact of smart combinations of graphene oxide and micro/nanosized sulfur particles on soil health and plant biomass accumulation

Abstract

Background: Elemental sulfur (S0) is a cost-efficient fertilizer and the least rapidly utilizable source of S for soil microorganisms and plants. Its bacterial-mediated oxidation to sulfates is dependent on particle size. Finely formulated (micronized, nanosized) S0 exerts enhanced oxidation rate and benefit due to nutrient availability and crop nutrition efficiency. Graphene oxide (GO) affects soil properties both negatively and positively. A pot experiment was carried out with lettuce using soil supplemented with S0 in different composition, applied alone or in combination with GO. The following variants were tested: control, GO, micro-S0, micro-S0 + GO, nano-S0, nano-S0 + GO. Results: Nanosized S0 improved most of enzyme activities (dehydrogenase, arylsulfatase, N-acetyl-β-d-glucosaminidase, β-glucosidase, phosphatase). However, respirations induced by d-glucose, protocatechuic acid, l-arginine were decreased. GO mitigated negative to neutral effect of micro-S0 in the soil pH, dehydrogenase and urease activity. Furthermore, micro-S0 positively affected basal respiration and respirations induced by d-trehalose and N-acetyl-β-d-glucosamine. Nano-S0 + GO improved plant biomass yield and enzyme activities. However, nano-S0 + GO significantly decreased all substate-induced respirations. Conclusions: The benefit of soil treatment with nano-/micro-sized S0 and its combination with GO on soil biological parameters was partially demonstrated. Graphical Abstract: [Figure not available: see fulltext.].