Editorial of “Sustainable Use and Management of Nonconventional Water Resources for Agricultural Development”

Editorial

Water availability is one of the basic factors that constitute a condition for the proper functioning of various ecosystems. Limitations in access to water, both temporal and spatial, lead to the search for alternative water resources that can be used in various sectors of the national economy. An example is agriculture, the main sector of the economy, which is responsible for food security. Using nonconventional water resources, such as brackish water, agricultural drainage water, and treated wastewater effluents, for crop cultivation could achieve food security for future generations. This scenario is essential in overcoming the issues related to the current expansion of agricultural lands with their irrigation systems, where continued water demand threatens the forestry sectors and food production, security, and safety. This Special Issue titled “Sustainable Use and Management of Nonconventional Water Resources for Agricultural Development” covers several topics that could guide stakeholders, decision makers, scientific communities, policymakers, and public and private sectors for the best management of nonconventional water resources for agricultural practices.

Alnaimy et al. [1] present the application of machine learning algorithms to identify the optimal areas for crop productivity and sustainable farming activities where the study was conducted in the northeastern Nile Delta region of Egypt. Their study explores how machine algorithms, such as Aptenodytes Forsteri Optimization (AFO), Random Vector Functional Link (RVFL), and sine cosine algorithm (SCA), could be used for the spatial prediction of soil capability. These soil capability classes are good (Class#2), fair (Class#3), poor (Class#4), and very poor (Class#5), representing 11.31%, 42.87%, 35.19%, and 10.61% of the total study area, respectively.

To determine the suitability of groundwater quality for agricultural activities, deep learning time series techniques were employed in Sohag, Egypt [2]. The water quality index (WQI) was created using ten groundwater quality parameters (pH, sulfate, nitrates, magnesium, chlorides, iron, total coliform, total dissolved solids, total hardness, and turbidity) at seven pumping wells. The study demonstrates that the WQI values are highly influenced by the contents of iron and magnesium in the groundwater, further assisting managers and policymakers in better managing groundwater resources in arid areas. Rainfall is considered another source of water supply for maintaining sustainable agricultural practices because a lack of rainfall causes a depletion in the groundwater available. For this purpose, the variability in rainfall over the Thamirabharani River Basin was investigated using the coefficient of variation (CV) and precipitation concentration index (PCI), in addition to the application of the Mann–Kendall (MK) test and an innovative trend analysis (ITA) method [3].

The improvement of agricultural practices is also illustrated by Marzougui et al. [4], using sewage sludge to support land fertilization in northwestern Tunisia. The physicochemical and microbiological parameters of sludge are defined, and then a combined strengths, weaknesses, opportunities, and threats (SWOTs) and analytical hierarchy process (AHP) methodology is used to define the strategies applicable for sustainable agricultural development. Economic, social, technical, environmental, and health dimensions are used to define reactive, adaptive, defensive, and proactive strategies suitable to other MENA countries with similar climatic, soil, and socio-economic conditions. Their study demonstrates that sludge could be reused as an organic fertilizer for fodder, industrial crops, and food crops with no contact with soil harvested at least 6 months after sludge application. Moreover, it is not recommended to reuse sludge for vegetables and directly eaten fruit, avoiding all health risks because of probable pathogenic contamination.

To maintain sustainable irrigation methods, another study employed an automatic irrigation system for rice crop cultivation in South Korea [5]. These systems included Internet of Things (IoTs) sensors and images, e.g., a ponding-depth sensor, an intake gate, a controller, and a drive motor, to monitor the irrigation characteristics in the test field. Their study demonstrates that the automatic irrigation system can enhance on-site water productivity by ≈12.7% and reduce the labor power required for paddy water management by ≈21.8% compared to conventional irrigation processes. Under this improved irrigation approach, the net present value (NPV) is positive, and the internal rate of return (IRR) reaches 8.6% (which is greater than the discount rate of 4.5%).

Other water sources, such as the reuse of carwash wastewater after proper treatment, could be employed in the agricultural sector. This hypothesis is defined in a study by Dadebo et al. [6], showing the application of coagulation/flocculation, electrochemical, oxidation, membrane, adsorption, biological, and hybrid methods for carwash wastewater treatment. The study demonstrates how a combined anaerobic digestion/oxidation scheme could be employed to degrade CWW-related pollutants and assist in developing an energy-efficient pathway for waste management. This study’s findings could encourage policymakers and stakeholders to implement sensible regulations that control the disposal and reuse of carwash wastewater to either directly or indirectly adopt the agenda 2030 with its seventeen SDGs, especially Target 2.4: “implement resilient agricultural practices” by providing unconventional water sources for irrigation.

In conclusion, this Special Issue provides comprehensive knowledge on the best utilization and management of nonconventional water resources, especially to maintain agricultural sustainability. This approach can maintain SDG#2, “Zero Hunger”, by achieving food security and promoting sustainable agriculture, and SDG#6, “Clean Water and Sanitation”, by ensuring the availability and sustainable management of water.