Soil salinization management for sustainable development: A review.

The expansion of irrigated agriculture is of paramount importance to feed the burgeoning global population. However, without proper management, this expansion can result in environmental problems of irrigation-induced soil salinization. A recent FAO estimate reported that a large portion of total global soil resources are degraded and this problem is persistently expanding. Many irrigated areas of the world are facing the twin problems of soil salinization and waterlogging and presently over 20% of the total global irrigated area is negatively affected by these problems. And, if left unattended, this problem could expand to over 50% of the total global irrigated areas by 2050. The proper management of the aforementioned soil salinization is imperative for achieving most of the Sustainable Development Goals (SDGs) of the United Nations. For example, soil salinization management is vital for achieving the 'Zero Hunger' (SDG2) and 'Life on Land' (SDG15) among other SDGs. This paper provides a comprehensive review of different measures used for managing the environmental problems of soil salinization. All the possible sources of related and up to date literature have been accessed and over 250 publications were collected and thoroughly analyzed for this review. The centrality of the environmental problems is provided. The background of the problems, managing rising water table to control soil salinization, the role of drainage frameworks, the conjunctive use of diverse water sources, utilization of numerical models, and the use of remote sensing and GIS systems are described. And the application of the aforementioned techniques and methods in various case study regions across the globe are discussed which is followed by discussion and research gaps. Derived from the literature analysis and based on the identified research gaps, some key recommendations for future research have been made which could be useful for the stakeholders. The literature analysis revealed that an all-inclusive approach for dealing with the aforesaid environmental problems has been barely considered in the previous studies. Similarly, the continuing impacts of growing salt-tolerant plants on soil characteristics and the environment in total have not been widely considered in the previous investigations. Likewise, better irrigation practices and improved cropping systems along with the long-term environmental impacts of a particular approach has not been extensively covered in these studies. Also, previous studies have scarcely incorporated economic, social, and environmental aspects of the salinization problem altogether in their analysis. The analysis suggested that an inclusive feedback-supported simulation model for managing soil salinization should be considered in future research as the existing models scarcely considered some vital aspects of the problem. It is also suggested to enhance the sensing methods besides retrieval systems to facilitate direct detection of salinization and waterlogging parameters at large-scales. The existing time-lag between occurrence and recording of various data is also suggested to improve in the future scenario by the usage of information from multiple satellites that lessens the problems of spatial resolution by increasing the system efficiency.