Frontiers in Microbiology | www.frontiersin.org 1 June 2019 | Volume 10 | Article 1320 MINI REVIEW published: 18 June 2019 doi: 10.3389/fmicb.2019.01320 Edited by: Marc Gregory Dumont, University of Southampton, United Kingdom Reviewed by: Weiqi Wang, Fujian Normal University, China Genxing Pan, Nanjing Agricultural University, China *Correspondence: Pil Joo Kim pjkim@gnu.ac.kr Specialty section: This article was submitted to Terrestrial Microbiology, a section of the journal Frontiers in Microbiology Received: 03 December 2018 Accepted: 27 May 2019 Published: 18 June 2019 Citation: Das S, Kim GW, Hwang HY, Verma PP and Kim PJ (2019) Cropping With Slag to Address Soil, Environment, and Food Security. Front. Microbiol. 10:1320. doi: 10.3389/fmicb.2019.01320 Cropping With Slag to Address Soil, Environment, and Food Security Suvendu Das 1 , Gil Won Kim 2 , Hyun Young Hwang 3 , Pankaj Prakash Verma 1 and Pil Joo Kim 1,3 * 1 Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju, South Korea, 2 Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia, 3 Division of Applied Life Science, Gyeongsang National University, Jinju, South Korea The effective utilization of slag fertilizer in agriculture to neutralize soil acidity, improve crop productivity, mitigate greenhouse gas emissions, and stabilize heavy metals in contaminated soils turns it into a high value added product in sustainable agriculture. These effects could be due to the shift in microbial metabolism and/or modifcation of microbial habitats. At the system level, soil microorganisms play an integral role in virtually all ecosystem processes. There is a growing interest to reveal the underlying mechanisms of slag-microbe interactions and the contribution of soil biota to ecosystem functioning. In this perspective, we discuss the possible driving mechanisms of slag-microbe interactions in soil and how these slag-microbe interactions can affect crop yield, greenhouse gas emissions, soil carbon sequestration, and heavy metal stabilization in contaminated soils. In addition, we discuss the problems and environmental concerns in using slag in agriculture. Emphasis has been given for further research to validate the proposed mechanisms associated with slag-microbe interactions for increasing soil quality, crop productivity, and mitigating environmental consequences. While evaluating the slag amendment, effects on agriculture and environment, the potential risks, socio-economics, techno-economics, and ethics should be assessed. Keywords: microbial dynamics, silicate fertilization, slag, greenhouse gas emissions, carbon sequestration INTRODUCTION Over the past decades, with the rapid growth of industrialization, the higher volume of byproducts (slag) generated from iron/steel production draw attention to the need for its recycling in an increasingly efcient way. With the increase in population, the available land to dispose of large amounts of slag in landfll sites is reduced and the disposal cost is becoming increasingly higher. Moreover, the land flled with disposed slag has become an important source of pollution of air, water, and soil, which further adversely afects vegetation and human health (Branca and Colla, 2012). Te entry of heavy metals/metalloids into the food chain is a critical issue of current public health (Chand et al., 2015). From the perspective of natural resource conservation, environmental protection, and human health safety measures, recycling