Water footprint and virtual water flows from the Global South: Foundations for sustainable agriculture in periods of drought

A modified approach of the agricultural grey water footprint considering the nitrogen fixation effect of crops in China

The rapidly growing demand for food in human societies has led to the extensive use of fertilizers, significantly contributing to water pollution. Grey water footprints (GWF) serve as a crucial method for measuring Non-point Source (NPS) pollution, particularly in agriculture. Traditional assessments of agricultural GWF neglect biologically fixed nitrogen and the use of organic fertilizers. This research proposed a modified method to assess the GWF of Chinese agriculture from 2000 to 2020, considering the impact of Nitrogen fixation in crops and the use of organic fertilizer. We also analyzed the determinants of Agricultural Nitrogen Fixation Intensity (ANFI) using the Logarithmic Mean Divisia Index (LMDI) method to better understand factors influencing agricultural GWF. Our findings include (1) Grain cereals (e.g., maize, rice, and wheat) significantly contribute to nitrogen fixation in crop organs, accounting for 87.7%, whereas the other six economic crops contribute the rest of 12.3%. Human wastes account for Nitrogen emissions for 1.40%, and emissions by livestock product, red meat contributes 16.26%, while white meat, eggs, and milk collectively contribute 82.34%. (2) Across China, there is an overestimation of GWF by 22.4 hundred million m3 per year, about 5.13% of the total GWF measured by traditional methods. It appears that the overestimation of GWF in plain regions with more arable land tends to be somewhat more pronounced compared to plateau and coastal municipalities. Biotechnological advancements in the capacity of nitrogen fixation for key crops (e.g., maize, wheat, rice) can alleviate agricultural water pollution. The modified methodology provides a robust scientific basis for a more precise application of GWF assessments, highlighting the substantial overestimation by traditional methods in China.

A bibliometric analysis-based literature review of the relationship between sustainable water management and green innovations in the agricultural sector

Global water demand has grown intensively over the last three decades, and the predictions suggest this trend will continue. Sustainable Water Management (SWM) defines water-based principles and action frameworks interconnecting societal, economic, and environmental aspects to establish and maintain good practices serving long-term objectives related to water resources. Water scarcity, deterioration of water quality, less effective water technologies, hydrological changes caused by climate change, and increased water demand require the thorough revision of conventional approaches, new methods, and new policy measures. The research methodology in this paper includes a comprehensive review and bibliometric analysis of relevant literature on water management and sustainable development, including empirical studies, theoretical frameworks, and policy documents. The study explores the conceptual context of SWM, reveals the barriers hindering its core progress, evaluates the impact of green innovations on the development of novel operations, and gets an insight into the current policy and regulatory framework for SWM. Besides giving a review of the current practices and perspectives in SWM, the results of this study contribute to a deeper understanding of the complex relationship between sustainable water management and green innovations in the agricultural sector and provide possible directions toward adopting effective strategies and policies to promote a more intense permeation of the SWM approach.

A temporal analysis of the consequences of the drought regime on the water footprint of agriculture in the Guadalupe Valley, Mexico

Changes in water availability have a substantial impact on the sustainability and maintenance of agriculture, with water footprint (WF) being a robust methodology to assess these transformations. The Guadalupe Valley is one of the places with the highest agricultural production in Mexico. Despite its semi-arid climatic conditions, it provides high-quality crops that are well-positioned in the world. The historical trend of rainfall and temperatures between 1987 and 2017 was analyzed to identify climatic patterns in the territory. Through the calculations of the water footprint of Grapevine and Olive crops, the sensitivity of the crops to recurrent water deficit and their adaptation in their yields to drought episodes was identified. The reduction in precipitation and occurrence of extreme temperatures have contributed significantly towards augmenting crop evapotranspiration and, consequently, intensifying crop irrigation demands. As a result, there has been an apparent increase in the consumption of WFagricultural since 2007. Thus, the period of highest WFagricultural consumption was 2014 (Extremely dry), as opposed to 2011 (Very wet). In particular, the lowest WFgreen consumptions were observed in extremely dry years, that is, > 20% of the WFagricultural intensifying drought events. Therefore, these periods were compensated with higher uses of WFblue and WFgray, which are inversely correlated with precipitation, where vine crops consume 73% more WFagricultural compared to olive plantations, showing greater interannual variability. These results contribute to analyzing the temporal evolution of water consumption for agriculture, providing a basis for rational water use strategies.

Economic, environmental and social efficiency and effectiveness development in the sustainable crop agricultural sector: A systematic in-depth analysis review

Multi-dimensional inclusion of economic, environmental, and social sustainability spheres together are the most global concerns of the agricultural crop sector. Therefore, optimizing waste and natural resources guides researchers and policymakers to structure actions and strategies to attain sustainability. Several studies have been published around the world to choose between focusing on eco-efficiency or eco-effectiveness in different aspects. This work aims to systematically apply an updated review to critically assess the agricultural research articles' contributions among the assessment of those methods, models or tools, as well as a quantitative and qualitative in-depth analysis review to classify them, according to their mapping, functions, strengths, weaknesses, and logical relationships for the evaluation in the crop agricultural sector, which is expected to be needed in future to better understand the research gaps and select the appropriate methods for sustainability evaluation from different spheres (ecology, economy, and sociology). Of 242 peer-reviewed records from 2018 to the beginning of 2023, 135 reviews and articles gathered from Web of Science and Scopus meet the criteria to be examined. Our analysis revealed that the number of reviews is limited to approximately 4.5 %; most of the case studies were carried out in countries, such as China (36 %) and Brazil (6 %), and continents such as Europe (16 %). Depending on considered aspects, most studies evaluate the efficiency, effectiveness and derivatives using a set of tools, varying between the managerial tools applied for the macro-level structuration (DPSIR, EMA, and LCA) and mathematical tools applied for the micro-level quantification, subdivided into the visualization methods (GIS), and the optimization methods (DEA, SFA, MILP, FO). Thanks to their multifunctionality in considering different aspects of input, output and influence factors variables, the in-depth analysis study suggests the application of data envelopment and stochastic analysis to carry out a multidisciplinary evaluation for the socio-eco-efficiency or the socio-eco-effectiveness.