Preserving coastal agriculture: Nature-based solutions for the mitigation of soil salinization

Soil salinization significantly threatens agriculture and food security, leading to profound soil degradation and desertification, negatively impacting ecosystems. The accumulation of excessive salts has negative effects on soil structure, fertility, plant growth, crop yield, and microorganisms. This phenomenon is attributed to natural factors, such as dry climates and high evaporation rates, and human-induced factors, including not optimal irrigation practices, inadequate drainage systems, and excessive fertilizer use. The increased frequency of weather extremes driven by climate change exacerbates this global issue, especially along coastal areas where millions of people live. Here, the sea-level rise, and recently also drought, are causing, especially in river deltas, a progressive land degradation, which negatively impacts the sustainable development of coastal agriculture. The lack of rainfall leads to scarce river discharge and consequently favours marine water inland flow intrusion. Anthropogenic activities (e.g., dams, mining) are exacerbating the phenomenon. Urgent mitigation strategies are therefore necessary. This study explores the potential of Nature-based Solutions (NbS) as sustainable and resilient response to soil salinization, offering benefits to agriculture through revitalizing ecosystem services. In detail, we addressed the challenges and limitations of implementing natural barriers, wetlands, buffer zones, conversion to aquaculture, straw incorporation, microbial-based solutions, organic fertilizers, and low impact water storage facilities. In detail, we should start re-introducing, where possible, wetlands through renaturalisation strategies, aiming to create a virtuous ecological equilibrium in agricultural landscapes. Indeed, wetlands can offer a natural barrier to saltwater intrusion. Soil remediation of degraded areas, especially for those interested in sand mining or oil refineries, is necessary to make soils more resilient and reestablish missed ecosystems. Agriculture must be sustainable and adopt conservation practices to keep and improve soil organic carbon content (SOC). Soils rich in SOC can retain more water and are more resilient; thus, they are more prepared for prolonged pressure given by water scarcity and soil salinization.