Biosynthesis and chemical composition of nanomaterials in agricultural soil bioremediation: a review.

Nanomaterials (NMs) are currently being used in agricultural soils as part of a new bioremediation (BR) process. In this study, we reviewed the biosynthesis of NMs, as well as their chemical composition and prospective strategies for helpful and sustainable agricultural soil bioremediation (BR). Different types of NMs, such as nanoparticles, nanocomposites, nanocrystals, nano-powders, and nanotubes, are used in agricultural soil reclamation, and they reflect the toxicity of NMs to microorganisms. Plants (Sargassum muticum, Dodonaea viscose, Aloe Vera, Rosemarinus officinalis, Azadirachta indica, Green tea, and so on) and microorganisms (Escherichia coli, Shewanella oneidensis, Pleurotus sp., Klebsiella oxytoca, Aspergillus clavatus, and so on) are the primary sources for the biosynthesis of NMs. By using the BR process, microorganisms, such as bacteria and plants, can immobilize metals and change both inorganic and organic contaminants in the soil. Combining NMs with bioremediation techniques for agricultural soil remediation will be a valuable long-term solution.

Effect of pesticides on nitrification activity and its interaction with chemical fertilizer and manure in long-term paddy soils.

Effect of pesticides on nitrification activity and its interaction among heavy metal concentrations (HMCs), antibiotic resistance genes (ARGs), and ammonia monooxygenase (amoA) genes of long-term paddy soils is little known. The aim was to study the effect of pesticides on net nitrification rate (NR), potential nitrification rate (NP), HMCs, ARGs (sulI, sulII, tetO, and tetQ), and amoA (amoA-AOA, amoA-AOB, and amoA-NOB) genes in long-term treated paddy soils. NR and NP were significantly decreased (p < 0.05), whereas HMCs (Pb2+, Cu2+, Zn2+, and Fe3+) were a significantly increased (p < 0.05) in chemical fertilizer with pesticide treated paddy soils as compared with chemical fertilizer treated paddy soils. The scatter plot matrix indicated that total carbon (TC), soil organic carbon (SOC), total nitrogen (TN), and Fe were linearly correlated with NR and NP in long-term treated paddy soils. ARGs and amoA genes were significantly decreased (p < 0.05) in chemical fertilizer and manure with pesticide treated paddy soils. Overall, the result indicated the response of pesticide and their combination of manure with pesticide interaction present in long-term paddy soils, which will play a great role in the control uses of pesticides, manure, and chemical fertilizers in paddy soils and protect the nitrogen cycle as well as environment.