Evaluation of the GreyWater Footprint Comparing the Indirect Effects of Different Agricultural Practices

Increasing global food demand and economic growth result in increasing competition over scarce freshwater resources, worsened by climate change and pollution. The agricultural sector has the largest share in the water footprint of humanity. While most studies focus on estimating water footprints (WFs) of crops through modeling, there are only few experimental field studies. The current work aims to understand the effect of supposedly better agricultural practices, particularly precision agriculture (variable rate application of fertilizers and pesticides) and conservation agriculture (minimum, strip, or no-tillage), on water deterioration and water pollution. We analyzed the results from an experimental field study in the northeast of Italy, in which four different crops are grown across three years of crops rotation. We compared minimum, strip, and no-tillage systems undergoing variable to uniform rate application. Grey WFs are assessed based on a field dataset using yield maps data, soil texture, and crop operations field. Leaching and associated grey WFs are assessed based on application rates and various environmental factors. Yields are measured in the field and recorded in a precision map. The results illustrate how precision agriculture combined with soil conservation tillage systems can reduce the grey water footprint by the 10%. We assessed the grey Water Footprint for all the field operation processes during the three-year crop rotation

Decrease the Water Footprint using precision agriculture: a comparison between conventional and conservative agriculture

Agriculture makes competition on the freshwater use and affects negatively its availability, worsened by climate change and pollution. The challenge to reduce the water use has to deal with the improvement of water use efficiency and the abatement of pollution. This is possible considering a sustainable water consumption. Indeed, agricultural processes are the main responsible of the global water footprint. Since there are no many studies of water footprint on the operative phases of soil preparation, this study aims to understand how agricultural practices and a sustainable crop management can reduce the water usage and the water pollution. For this reason, the effect of conservation tillage system on water footprint has been studied in a three years defined crops rotation of maize, soybeans, wheat, and canola. The case study is located in the Veneto plain in Italy. A spatial variability analysis and the adoption of precision agriculture technologies were tested. Water footprint was examined using climate data, soil texture analysis, crop coefficients and each chemical input applied to each treatment during crop cycles. Results highlight that the water footprint between traditional and conservative tillage systems is significantly different. Minimum tillage combines positively the advantage of the water footprint reduction and a good yield. Precision agriculture affects mostly the grey water footprint, reducing operational inputs, such as pesticides and fertilizers consume. On the other hand, precision agriculture led to an increasing crop yield on average comparing the same techniques managed with uniform rate application. The study shows a reduction of water footprint within precision agriculture, especially in conservative tillage in comparison with the conventional tillage. These conservative techniques, combined with the precision agriculture, minimize the wastage and save input, avoiding environmental dispersion, and reducing its impact

Weak and Strong Sustainability of Irrigation: A Framework for Irrigation Practices Under Limited Water Availability

Agriculture strongly relies on irrigation. While irrigated land accounts for roughly 20% of the global cultivated area, it contributes to about 40% of crop production. In the last few decades, the growing demand for agricultural commodities has translated into an increasing pressure on the global freshwater resources, often leading to their unsustainable use. Here we investigate the sustainability of irrigation, balancing farmers' profit generation objectives and the needs of ecological systems. We ask the question "sustainability of what?", to stress how the sustainability of irrigation is often evaluated with respect the opposing needs of humans and nature. While from the farmers' perspective irrigation is sustainable when it provides uninterrupted access to water resources at a price not exceeding the marginal revenue they generate (clearly without accounting for environmental externalities), from the standpoint of water resources, irrigation is sustainable if it does not deplete freshwater stocks or environmental flows. We invoke the notions of 'weak' and 'strong' sustainability to develop a novel framework for the evaluation of tradeoffs between human needs and the conservation of natural capital. Through the analysis of criteria of performance, we relate water deficit and irrigation overuse to the reliability and resilience of irrigation. This approach is applied to the case of Australia, a major agricultural country affected by water scarcity. The application of the framework to the case of Australia shows how this approach can be used to highlight areas in which irrigation contributes to a weakly sustainable use of water resources with impacts on environmental flows and groundwater stocks. Solutions, such as increasing efficiencies or reducing water applications through the adoption of deficit irrigation, can enhance water sustainability in some water scarce locations

Sustainability assessment of agriculture water use under water scarcity limitation and climate change adaptation

Irrigation accounts for about 70% of the global freshwater withdrawals and 90% of consumptive water uses. With 40% of irrigation water consumption occurring in water scarce areas, there is a need to understand to what extent freshwater can be sustainably used in agriculture without compromising environmental flows or depleting groundwater stocks. To date, methods that can be used to evaluate the vulnerability of the water system to climate change and the sustainability of water use for irrigation often fail to provide an integrated analysis of the biophysical and economic dimensions of water use. Here we develop a new approach to evaluate the sustainability of water use in agriculture in conditions of water scarcity. We propose a framework that accounts for both socio-economic and environmental aspects of water sustainability based on three criteria expressing the reliability, resilience, and vulnerability of irrigation. Reliability is calculated as the probability that the system is able to meet irrigation need (i.e. irrigation water demand does not exceed water availability). Resilience expresses the system\u2019s ability to adapt to a changing condition and recover from a shock (i.e. a drought or conditions of water stress). Vulnerability is the magnitude (or \u2018severity\u2019) of the water deficit (i.e. insufficient irrigation water availability) the system is exposed to. Similar metrics are used to characterize the economic sustainability of irrigation. The evaluation of performance is based on the frequency of a deficit situation on each dimension of sustainability. The criteria of performance are aggregated into sub-indicators for each dimension of sustainability. The application of this framework to the case of Australian agriculture for the 2002-2016 period shows that Australia suffers from a high level of water scarcity, especially during the growing season. The analysis of the framework highlights the sustainability and unsustainability of the Australian water use system both in space and time. This analysis informs new criteria for managing a sustainable use of water resources, which is becoming challenging for stakeholders. Farmers need to adopt water management approaches that allow for a sustainable water use for irrigation and overcome water scarcity constraints

Impact of mechanisation on soil loss in terraced vineyard landscapes

Soil loss poses a threat to hilly and mountainous areas, particularly where local economies strongly depend on agricultural production. Among agricultural landscapes, vineyards are responsible for the highest erosion rates, particularly in steep-slope landscapes. The impact of vineyard mechanisation on soil loss is only marginally explored in published literature. This study provides an estimation of the annual soil loss rate by application of the Revised Universal Soil Loss Equation (RUSLE) in 24 terraced vineyards located in north-eastern Italy. Field observations showed that 13 vineyards consisted of fully mechanised fields, 5 vineyards had no form of mechanisation, while in 6 vineyards a mixture of practices was found. Soil erodibility (K factor) was derived for these practices (based on soil characteristics and varying degrees of compaction), while slope length and steepness (LS factors) were calculated from a 1-m LiDAR-based DTM, and remaining factors were based on datasets by the European Soil Data Centre. Mechanised fields showed 29% higher erosion rates than non-mechanised fields (respectively 53.9 and 69.5 t ha-1 y-1), although this is not statistically significant. Still, the direct impact of mechanisation is underestimated in this comparison, due to the predominant steep slopes in the manually cultivated fields. Furthermore, estimated soil loss from mechanised fields in addition to mechanised paths and roads is significantly higher by 37% than non-mechanised fields. This study thus offers an indication of how machinery and related soil compaction and transformation of terraces and infrastructure, increases soil loss risk

Leaf water relations in Diospyros kaki during a mild water deficit exposure

The resistance mechanisms (stress avoidance and stress tolerance) developed by persimmon plants (Diospyros kaki L. f. grafted on Diospyros lotus L.) in response to mild water stress and the sensitivity of continuously (on a whole-day basis) and discretely (at predawn and midday) measured indicators of the plant water status were investigated in 3-year old ‘Rojo Brillante’ persimmon plants. Control (T0) plants were drip irrigated in order to maintain soil water content at levels slightly above soil field capacity (102.3% of soil field capacity) and T1 plants were drip irrigated for 33 days in order to maintain the soil water content at around 80% of soil field capacity. The results indicated persimmon plants confront a mild water stress situation by gradually developing stomata control (stress avoidance mechanism) and exhibiting some xeromorphic characteristic such as high leaf relative apoplastic water content, which could contribute to the retention of water at low leaf water potentials. In addition, sap flow measurements made by the heat-pulse technique were seen to be the most suitable method for estimating persimmon water status, because it provided the highest signal intensity (actual value/reference value):noise (coefficient of variation) ratio in almost all intervals of time considered and provides continuous and automated registers of the persimmon water status in real time. © 2019 The AuthorsWe are grateful to the Arnau family from Explotaciones Ecológicas Harisa S.L. and Mr. J. Melgares from Oficina Comarcal Agraria Huerta de Murcia (Autonomous Comunity of the Region of Murcia) for all the help we have been given. AG and AJM acknowledge the postdoctoral financial support received from Ramón Areces Foundation and Juan de la Cierva program, respectively . IG is a predoctoral student at the Miguel Hernández University. Also, this work is a result of the PR internship (19925/IV/15) funded by the Seneca Foundation - Agency for Science and Technology in the Region of Murcia under the Jiménez de la Espada Program for Mobility, Cooperation and Internationalization.Peer reviewe

Analysis of the Water Footprint of Agriculture Products and the Related MItigation Strategies

Agriculture is the major player of human appropriation of water resources. About 70% of global freshwater withdrawals are used for irrigation to sustain global crop production. In fact, irrigated areas account for 18% of global croplands which contribute for 40% of global food production. In addition, the 40% of the global irrigation practice is unsustainable because it depletes environmental flows and/or groundwater stocks. In order to preserve the water resource, the European Water Framework Directive lead to an efficient use of freshwater and it gives guidelines to preserve the qualitative natural status of water bodies. To achieve this objective, the impact assessment needs suitable indicators to be computed. The use of an environmental indicator of water shortage can enhance better the decision-making process for water saving and leading a reduction on water stress from human activities. This thesis integrates the concept of the water footprint with other environmental indicators to analyse sustainability and comparing the related performance of different agricultural practices. The main objective of this thesis is to find solutions to mitigate the impact of agricultural crop production on water resource identifying best practices quantifying the water footprint and water-related indexes. To do that, we combined different indicators of water use improving a sustainability framework for different agricultural products and field management. The first step was to classify and making a clustered analysis of agricultural products identifying their specific environmental performance and their related water footprint. Then, the definition of a framework for sustainable water use in the agriculture sector was done, considering both environmental and economic aspect of sustainability. The second step focused on the definition of best agricultural practices for a sustainable water consumption comparing different soil and field management. Results were supported by different case studies that promoted innovative solutions to mitigate water footprint and the impact on water resource by improving the agricultural production system; this can be improved by encouraging awareness and sensitivity of farmers to some ecological initiatives.L'agricoltura svolge un ruolo importante nello sfruttamento della risorsa idrica. Si pensi che circa il 70% del consumo di acqua a livello globale viene utilizzata per scopi agricoli, primo fra tutti l’irrigazione per la produzione di colture che potranno essere consumate sia per l’alimentazione umana, sia per quella zootecnica. A livello mondiale, le aree irrigate rappresentano circa il 18% del totale delle superfici coltivate, contribuendo per il 40% alla produzione mondiale di cibo. Se è pur vero che la pratica irrigua crea un beneficio all’agricoltura perché ne aumenta la produttività, è vero anche che a conti fatti circa il 40 per cento dell’acqua consumata a livello mondiale per scopi irrigui viene utilizzata in maniera del tutto insostenibile. Questo perché la sottrazione di volumi d’acqua all’ambiente comporta una riduzione dei deflussi ecologici e/o delle riserve d’acqua sotterranea, in particolar modo si pensi alle riserve di acqua fossile. La Direttiva Quadro sulle Acque (2000/CE/60) consente solo l’uso efficiente delle acque superficiali e di falda e fornisce delle raccomandazioni su come preservare lo stato naturale qualitativo dei corpi idrici. L'utilizzo di un indicatore ambientale, quale l’indicatore di impronta idrica, fornisce informazioni utili e volte a migliorare il processo decisionale per il risparmio idrico e a ridurre lo stress idrico causato dalle attività umane. L'obiettivo principale di questa tesi è quello di trovare soluzioni utili a mitigare l'impatto della produzione agricola sulla risorsa idrica individuando pratiche agronomiche più sostenibili. A tal fine, lo scopo generale dello studio è quello di integrare il concetto di impronta idrica con altri indicatori ambientali per confrontare le relative prestazioni di diversi processi agricoli valutando il loro grado di sostenibilità. Dapprima, si è cercato di classificare e raggruppare le famiglie dei prodotti agroalimentari in base alle loro specifiche prestazioni ambientali e la relativa impronta idrica per definire la sostenibilità della loro produzione e di conseguenza del loro consumo. Successivamente, è stato definito uno schema per lo studio della sostenibilità dell’uso dell’acqua in agricoltura, valutandone sia l'aspetto ambientale che quello economico. In secondo luogo, sono state individuate pratiche agricole che riducessero l’impronta idrica durante il processo produttivo e favorissero una maggiore salvaguardia della risorsa idrica. A supporto, diversi casi studio sono stati analizzati per valutare diverse gestioni del suolo, delle fasi agronomiche in campo e del consumo di acqua con maggiore attenzione alla pratica irrigua. Le soluzioni fornite attraverso i risultati della tesi sostengono soluzioni innovative per mitigare l'impronta idrica e l'impatto dell’attività agricola sulla risorsa idrica. Questo può ancora essere migliorato ed incentivato promuovendo la sensibilizzazione degli agricoltori alla gestione sostenibile dell’agro-ambiente e incoraggiando il mercato alimentare a premiare tali iniziative ecologiche

Evaluation of the Grey Water Footprint Comparing the Indirect Effects of Different Agricultural Practices

Increasing global food demand and economic growth result in increasing competition over scarce freshwater resources, worsened by climate change and pollution. The agricultural sector has the largest share in the water footprint of humanity. While most studies focus on estimating water footprints (WFs) of crops through modeling, there are only few experimental field studies. The current work aims to understand the effect of supposedly better agricultural practices, particularly precision agriculture (variable rate application of fertilizers and pesticides) and conservation agriculture (minimum, strip, or no-tillage), on water deterioration and water pollution. We analyzed the results from an experimental field study in the northeast of Italy, in which four different crops are grown across three years of crops rotation. We compared minimum, strip, and no-tillage systems undergoing variable to uniform rate application. Grey WFs are assessed based on a field dataset using yield maps data, soil texture, and crop operations field. Leaching and associated grey WFs are assessed based on application rates and various environmental factors. Yields are measured in the field and recorded in a precision map. The results illustrate how precision agriculture combined with soil conservation tillage systems can reduce the grey water footprint by the 10%. We assessed the grey Water Footprint for all the field operation processes during the three-year crop rotation

Sustainable patterns of main agricultural products combining different footprint parameters

The world population is increasing, and the human diet is becoming of considerable concern for human welfare. Furthermore, natural resources are overexploited, and governments need policies for the proper management of the environment. Sustainable agriculture can provide some solutions, as it minimizes inputs, wastes or pollution. The aim of the present study is to provide a combined analysis of different footprint approaches to allow comparison of different agricultural and livestock products regarding the efficiency of resource exploitation. Water consumption, greenhouse gas emissions and energy indexes are included in this study as footprint indicators. The study takes advantage of indexes collected from an extensive bibliography focused on different fresh agricultural products; the target is the definition of a timetable of footprints for agricultural products. Starting from a top-down perspective, an analysis of the environmental footprint for different products is an approach to understanding which products can be more sustainable for the human diet. For this reason, this study distinguishes different clusters in different sub-clusters of vegetable products and animal products. The comparison of the footprint indicators of water consumption regarding yield, greenhouse gas emissions equivalent, and energy provide a ranking of sustainability for a given product. Ultimately, this work seeks to propose an original pattern of food sustainability, allowing an adequate quantitative comparison of agriculture products for a more conscious human diet

L\u2019impronta idrica che premia produttore e consumatore

Le politiche comunitarie si adoperano per incentivare il risparmio idrico e ridurre il rischio di contaminazione da inquinanti al fine di raggiungere uno stato qualitativo dei corpi idrici buono. Lo strumento in mano agli utilizzatori \ue8 un indicatore utile ai fini economico-produttivi di razionalizzazione delle risorse, sostenibilit\ue0 ambientale e ritorno economic