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To meet the global demand for food, several factors have been deployed by agriculturists to supply plants with nitrogen. These factors have been observed to influence the soil nitrification process. Understanding the aftermath effect on the environment and health would provoke efficient management. We review literature on these factors, their aftermath effect on the environment and suggest strategies for better management. Synthetic fertilizers and chemical nitrification inhibitors are the most emphasized factors that influence the nitrification process. The process ceases when pH is <5.0. The range of temperature suitable for the proliferation of ammonia oxidizing archaea is within 30 to 37oC while that of ammonia oxidizing bacteria is within 16 to 23oC. Some of the influencing factors excessively speed up the rate of the nitrification process. This leads to excess production of nitrate, accumulation of nitrite as a result of decoupling between nitritation process and nitratation process. The inhibition mechanism of chemical nitrification inhibitors either causes a reduction in the nitrifying micro-organisms or impedes the amoA gene's function. The effects on the environment are soil acidification, global warming, and eutrophication. Some of the health effects attributed to the influence are methemoglobinemia, neurotoxicity, phytotoxicity and cancer. Biomagnification of the chemicals along the food chain is also a major concern. The use of well-researched and scientifically formulated organic fertilizers consisting of microbial inoculum, well-treated organic manure and good soil conditioner are eco-friendly. They are encouraged to be used to efficiently manage the process. Urban agriculture could promote food production, but environmental sustainability should be ensured.

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Nitrifying bacteria and archaea are ubiquitous and can transform ammonia locked up in soil or manure into nitrate, a more soluble form of nitrogen. However, nitrifying bacteria and archaea inhabiting maize rhizosphere have not been fully explored. This study evaluates the diversity and abundance of nitrifying bacteria and archaea across different growth stages of maize using 16S amplicon sequencing. Moreover, the influence of environmental factors (soil physical and chemical properties) on the nitrifying communities was evaluated. Rhizosphere soil DNA was extracted using Nucleospin Soil DNA extraction kit and sequenced on Illumina Miseq platform. MG-RAST was used to analyze the raw sequences. The physical and chemical properties of the soil were measured using standard procedure. The results revealed 9 genera of nitrifying bacteria; Nitrospira, Nitrosospira, Nitrobacter, Nitrosovibrio, Nitrosomonas, Nitrosococcus, Nitrococcus, unclassified (derived from Nitrosomonadales), unclassified (derived from Nitrosomonadaceae) and 1 archaeon Candidatus Nitrososphaera. The Nitrospirae phyla group, which had the most nitrifying bacteria, was more abundant at the tasselling stage (67.94%). Alpha diversity showed no significant difference. However, the Beta diversity showed significant difference (p = 0.01, R = 0.58) across the growth stages. The growth stages had no significant effect on the diversity of nitrifying bacteria and archaea, but the tasselling stage had the most abundant nitrifying bacteria. A correlation was observed between some of the chemical properties and some nitrifying bacteria. The research outcome can be put into consideration while carrying out a biotechnological process that involves nitrifying bacteria and archaea.

Sustainable intensification is a means that proffer a solution to the increasing demand for food without degrading agricultural land. Maize is one of the most important crops in the industrial revolution era, there is a need for its sustainable intensification. This review discusses the role of maize in the industrial revolution, progress toward sustainable production, and the potential of nitrifying bacteria and archaea to achieve sustainable intensification. The era of the industrial revolution (IR) uses biotechnology which has proven to be the most environmentally friendly choice to improve crop yield and nutrients. Scientific research and the global economy have benefited from maize and maize products which are vast. Research on plant growth-promoting microorganisms is on the increase. One of the ways they carry out their function is by assisting in the cycling of geochemical, thus making nutrients available for plant growth. Nitrifying bacteria and archaea are the engineers of the nitrification process that produce nitrogen in forms accessible to plants. They have been identified in the rhizosphere of many crops, including maize, and have been used as biofertilizers. This study's findings could help in the development of microbial inoculum, which could be used to replace synthetic fertilizer and achieve sustainable intensification of maize production during the industrial revolution.