Agricultural Sciences: Techniques and Innovations Vol. 9

Microplastic (MP) contamination in agricultural soils has emerged as a pervasive environmental challenge, driven by extensive plastic production and inadequate waste management practices. Since the mid-twentieth century, global plastic output has exceeded 8,000 million tonnes, a substantial fraction of which has fragmented into microplastics (<5 mm), enabling their widespread distribution across agroecosystems. This chapter critically examines the sources, environmental pathways, and mechanistic impacts of MPs within the agro-pedospheric system, with particular emphasis on soil structure, microbial dynamics, and crop productivity. Microplastics enter agricultural soils through diverse anthropogenic routes, including plastic mulch degradation, biosolid application, wastewater irrigation, atmospheric deposition, and organic amendments. Once incorporated, MPs induce multifaceted alterations in soil physical, chemical, and biological properties. Structural disruptions include reductions in bulk density, porosity, and aggregate stability, which collectively impair water retention and nutrient cycling processes. At the biological level, MP exposure alters soil microbial community composition, reduces microbial biomass and enzymatic activity, and disrupts key functions such as nitrogen fixation and carbon mineralisation. These changes adversely affect plant growth by inhibiting seed germination, root development, nutrient acquisition, and overall crop performance, thereby posing a significant risk to agricultural sustainability and food security. The chapter further evaluates emerging remediation strategies, including biochar application, microbial bioaugmentation, phytoremediation, and the adoption of biodegradable lignocellulosic bioplastics as sustainable alternatives to conventional plastics. While these approaches demonstrate promising potential, their large-scale applicability and long-term effectiveness require further validation under field conditions. Overall, this chapter provides a comprehensive synthesis of current knowledge, identifies critical research gaps, and highlights the need for integrated management strategies and policy interventions to mitigate microplastic pollution and ensure resilient agroecosystems.