Many of the world's soils are experiencing degradation at an alarming rate. Climate change and some agricultural management practices, such as tillage and excessive use of chemicals, have all contributed to the degradation of soil fertility. Arbuscular Mycorrhizal Fungi (AMFs) contribute to the improvement of soil fertility. Here, a short review focusing on the role of AMF in improving soil fertility is presented. The aim of this review was to explore the role of AMF in improving the chemical, physical, and biological properties of the soil. We highlight some beneficial effects of AMF on soil carbon sequestration, nutrient contents, microbial activities, and soil structure. AMF has a positive impact on the soil by producing organic acids and glomalin, which protect from soil erosion, chelate heavy metals, improve carbon sequestration, and stabilize soil macro-aggregation. AMF also recruits bacteria that produce alkaline phosphatase, a mineralization soil enzyme associated with organic phosphorus availability. Moreover, AMFs influence the composition, diversity, and activity of microbial communities in the soil through mechanisms of antagonism or cooperation. All of these AMF activities contribute to improve soil fertility. Knowledge gaps are identified and discussed in the context of future research in this review. This will help us better understand AMF, stimulate further research, and help in sustaining the soil fertility.

Phosphorus is an important primary nutrient required by plants in large quantities. The various forms of P that plants can take up are the primary monobasic phosphate ion (H₂PO₄^-), secondary dibasic phosphate ion (HPO₄^2-) and phosphate ion (PO₄^3-). In tropical soils, phosphorus adsorption is a major process that controls its availability to crops. Soils with low phosphorus adsorption capacity are often unable to supply adequate phosphorus to the growing crops thereby affecting their yields. This paper reviews the phosphorus adsorption phenomenon in a tropical soil. The review showed that Langmuir isotherm, Freundlich isotherm, Brunauer-Emmett-Teller (BET) isotherm, Dubinin-Radushkevich, and Temkin isotherm are the mostly used isotherms models for describing phosphorus adsorption. From the review, soil acidity and alkalinity, soil temperature and the electrical potential of clay surface are the main factors influencing phosphorus adsorption. Also, precipitation was discovered to be the main mechanism of P adsorption in tropical soils. Fertilization practices such as the addition of organic manure, crop residues, rock phosphate, water-soluble P fertilizers and incorporation of phosphorus solubilizing organism are highly recommended to increase P solubility and availability in highly weathered soil.

Peatlands play a critical role in the global carbon cycle, storing large amounts of carbon because of a net imbalance between primary production and the microbial decomposition of the organic matter. Nevertheless, peatlands have historically been drained for energy sources (e.g. peat briquettes), forestry, or agriculture - practices that could affect the quality of the soil organic matter (SOM) composition, hydrophobicity and humification index. This study compared the effect of land use change on the quality and composition of peatland organic material in Co-Offaly, Ireland. Specifically, drained and grazing peat (grassland), drained and forest plantation peat (forest plantation), drained and industrial cutaway peat (cutaway bog) and an undrained actively accumulating bog (as a reference for natural peatland) were studied. Fourier-transform infrared spectroscopy (FTIR) was used to examine the organic matter quality, specifically the degree of decomposition (DDI), carbon chemistry signatures, hydrophobicity and humification index. The ratio of hydrophobic to hydrophilic group intensities was calculated as the SOM hydrophobicity. In general, there is greater variance in the carbon chemistry signature, such as aliphatic methyl and methylene, C=O stretching of amide groups, aromatic C=C, strong H-bond C=O of conjugated ketones and O–H deformation and C– O stretching of phenolics and secondary alcohols of the peat samples from industrial cutaway bog samples than in the grassland and forest plantation samples. The hydrophobicity and the aromaticity of the soil organic matter (SOM) are significantly impacted by land use changes, with a trend of order active bog > forest plantation > industrial cutaway bog > grassland. A comparison of the degree of decomposition index of the peat from active bog showed a more advanced state of peat degradation in grassland and industrial cutaway bog and, to a lesser extent, in forest plantation.

Copper is a naturally occurring trace element present in all environmental media, including soil, sediment, air and water. It is an essential micronutrient critical for cell function, playing a vital role in processes. Copper contamination to agricultural soils is of great concern due to its wide and continuous use in agriculture and horticulture as fertilizers and fungicide. Copper contaminated soil is mainly attributed to agriculture activities such as continuous application of copper-based fungicides and pesticides application. A minireview was carried out using peer-reviewed articles published from 2000 to 2017, which methods of remediating copper soil. The AGORA and Google Scholar databases were used to conduct the search for articles using the terms copper and phytoremediation, Copper and Biological remediation, Copper and soil washing OR physical methods. Following these searches, 19 journal articles out of a total of 191 articles satisfied criteria for inclusion and were used in the final systematic review. The study showed that remediation technology for copper contaminated soil is divided into physical, chemical and biological categories. Physical methods are laborious and costly but can be applied to highly contaminated site; chemical methods have high efficiency and effective to remove the copper, but mostly popularized in a large scale; bioremediation methods including phytoremediation and microbial remediation are appropriate for large areas of soil contaminated by low concentrations of copper. The bioremediation methods are economical, eco-friendly but time consuming.

The present study employs a data review on the presence and aggregation of oxytetracycline (OTC) and resistance (AMR) bacteria in wastewater treatment plants (WWTPs), and the distribution of the contaminated effluent with the aid of shallow and deep ocean currents. The study aims to determine the fate of OTC and AMR bacteria in seafood, and demonstrate a relationship between AMR levels and human health. This review includes (1) OTC, (2) AMR bacteria, (3) heavy metals in aquatic environments, and their relationship. Few publications describe OCT in surface waters. Although OTC and other tetracyclines were found in 10 countries in relatively low concentrations, the continuous water mass movement poses a contamination risk for mariculture and aquaculture. There are 10 locations showing AMR bacteria in treated and untreated hospital effluent. Special effort was made to define the geography distribution of OTC, AMR bacteria, and heavy metals detected in WWTPs to show the likely dissemination in an aquatic environment. The presence of OTC in surface waters in Asia, USA, and Europe can potentially impact seafood globally with the aid of ocean currents. Moreover, low concentrations of heavy metals exert environmental pressure and contribute to AMR dissemination. Recommended solutions are (1) quantitative analysis of OTC, heavy metals, and AMR bacteria to define their main sources; (2) employing effective technologies in urban and industrial wastewater treatment; and (3) selecting appropriate modelling from Global Ocean Observing System to predict the OTC, heavy metals, and AMR bacteria distribution.