Blue Water Use Research Articles

How advances in animal efficiency and management have affected beef cattle's water intensity in the United States: 1991 compared to 2019.

Updating the static model by Beckett and Oltjen (1993), we determined that from 1991 to 2019, U.S. beef cattle blue water consumption per kg of beef decreased by 37.6%. Total water use for the U.S. cattle herd decreased by 29%. As with the 1993 model, blue water use included direct water intake by animals, water applied for irrigation of crops that were consumed by beef cattle, water applied to irrigated pasture, and water used to process animals at marketing. Numbers of cattle, crop production, and irrigation data were used from USDA census and survey data. On 1 January 2019, a total of 31.7-million beef cows and 5.8-million replacement heifers were in U.S. breeding herds, and 26-million animals were fed annually. In total, the U.S. beef cattle herd (feedlot and cull cows) produced 7.7-billion kg of boneless beef, an increase of 10% since 1991. Beef cattle directly consumed 599-billion L of water per year. Feedlot cattle were fed various grain and roughage sources corresponding to the regions in which they were fed. Feeds produced in a state were preferentially used by cattle in that state with that state's efficiency; any additional feedstuffs required used water at the national efficiency. Irrigation of crop feedstuffs for feedlot cattle required 5,920-billion L of water. Irrigated pasture for beef cattle production required an additional 4,121-billion L of water. Carcass processing required 91-billion L of water. The model estimated that in the U.S. 2,275 L of blue water was needed to produce 1 kg of boneless meat. As with the previous model, the current model was most sensitive to changes in the dressing percentage and the percentage of boneless yield in carcasses of feedlot cattle (62.8 and 65, respectively). In conclusion, with more beef, fewer cows, and lower rates of irrigation, beef cattle's water intensity has decreased at an annual rate of 1.34% over a 28-yr period.

Agricultural Adaptation to Reconcile Food Security and Water Sustainability Under Climate Change: The Case of Cereals in Iran.

In this study, we simulate the crop yield and water footprint (WF) of major food crops of Iran on irrigated and rainfed croplands for the historical and the future climate. We assess the effects of three agricultural adaptation strategies to climate change in terms of potential blue water savings. We then evaluate to what extent these savings can reduce unsustainable blue WF. We find that cereal production increases under climate change in both irrigated and rainfed croplands (by 2.6-3.1 and 1.4-2.3 million t yr-1, respectively) due to increased yields (6.6%-78.7%). Simultaneously, the unit WF (m3 t-1) tends to decrease in most scenarios. However, the annual consumptive water use increases in both irrigated and rainfed croplands (by 0.3-1.8 and 0.5-1.7 billion m3 yr-1, respectively). This is most noticeable in the arid regions, where consumptive water use increases by roughly 70% under climate change. Off-season cultivation is the most effective adaptation strategy to alleviate additional pressure on blue water resources with blue water savings of 14-15 billion m3 yr-1. The second most effective is WF benchmarking, which results in blue water savings of 1.1-3.5 billion m3 yr-1. The early planting strategy is less effective but still leads to blue water savings of 1.7-1.9 billion m3 yr-1. In the same order of effectiveness, these three strategies can reduce blue water scarcity and unsustainable blue water use in Iran under current conditions. However, we find that these strategies do not mitigate water scarcity in all provinces per se, nor all months of the year.

Remote sensing assessment of available green water to increase crop production in seasonal floodplain wetlands of sub-Saharan Africa

Producing more food for a growing population requires sustainable crop intensification and diversification, particularly in high-potential areas such as the seasonal floodplain wetlands of sub-Saharan Africa (SSA). With emerging water shortages and concerns for conserving these multi-functional wetlands, a further expansion of the cropland area must be avoided as it would entail increased use of blue water for irrigation and infringe on valuable protected areas. We advocate an efficient use of the prevailing green water on the existing cropland areas, where small-scale farmers grow a single crop of rainfed lowland rice during the wet season. However, soil moisture at the onset of the rains (pre-rice niche) and residual soil moisture after rice harvest (post-rice niche) may suffice to cultivate short-cycled crops. We developed a methodological approach to analyze the potential for green water cultivation in the pre- and post-rice niches in the Kilombero Valley Floodplain in Tanzania, as a representative case for seasonal floodplain wetlands in SSA. The three-step approach used open-access remote sensing datasets to: (i) extract cropland areas; (ii) analyze soil moisture conditions using evaporative stress indices to identify the pre- and post-rice niches; and (iii) quantify the green water availability in the identified niches through actual evapotranspiration (AET).We identified distinct patterns of green water being available both before and after the rice-growing period. Based on the analyses of evaporative stress indices, the pre-rice niche tends to be longer (~70 days with average AET of 20–40 mm/10-day) but also more variable (inter-annual variability >30%) than the post-rice niche (~65 days with average AET of 10–30 mm/10-day, inter-annual variability <15%). These findings show the large potential for cultivating short-cycled crops beyond the rice-growing period, such as green manure, vegetables, maize, and forage legumes, by shifting a portion of the nonproductive AET flows (i.e., soil evaporation) to productive flows in form of crop transpiration. A cropland area of 1452 to 1637 km2 (53–60% of the total cropland area identified of 2730 km2) could be cultivated using available green water in the dry season, which shows the significance of such change for food security, livelihoods, and resilience of the agricultural community in Kilombero. A wider application of the developed approach in this study can help identifying opportunities and guiding interventions and investments towards establishing sustainable intensification and diversification practices in floodplain wetlands in SSA.

Evaluation of foods, drinks and diets in the Netherlands according to the degree of processing for nutritional quality, environmental impact and food costs

ObjectiveThis study investigates nutritional quality, environmental impact and costs of foods and drinks and their consumption in daily diets according to the degree of processing across the Dutch population.DesignThe NOVA classification was used to classify the degree of processing (ultra-processed foods (UPF) and ultra-processed drinks (UPD)). Food consumption data were derived from the Dutch National Food Consumption Survey 2012–2016. Indicators assessed were nutritional quality (saturated fatty acids (SFA), sodium, mono and disaccharides (sugar), fibre and protein), environmental impact (greenhouse gas (GHG) emissions and blue water use) and food costs.SettingThe Netherlands.ParticipantsFour thousand three hundred thirteen Dutch participants aged 1 to 79 years.ResultsPer 100 g, UPF were more energy-dense and less healthy than unprocessed or minimally processed foods (MPF); UPF were associated with higher GHG emissions and lower blue water use, and were cheaper. The energy and sugar content of UPD were similar to those of unprocessed or minimally processed drinks (MPD); associated with similar GHG emissions but blue water use was less, and they were also more expensive. In the average Dutch diet, per 2000 kcal, ultra-processed foods and drinks (UPFD) covered 29% (456 g UPF and 437 g UPD) of daily consumption and 61% of energy intake. UPFD consumption was higher among children than adults, especially for UPD. UPFD consumption determined 45% of GHG emissions, 23% of blue water use and 39% of expenses for daily food consumption. UPFD consumption contributed 54% to 72% to daily sodium, sugar and SFA intake.ConclusionsCompared with unprocessed or minimally processed foods and drinks, UPF and UPD were found to be less healthy considering their high energy, SFA, sugar and sodium content. However, UPF were associated higher GHG emissions and with less blue water use and food costs. Therefore daily blue water use and food costs might increase if UPF are replaced by those unprocessed or minimally processed. As nutritional quality, environmental impacts and food costs relate differently to the NOVA classification, the classification is not directly applicable to identify win–win-wins of nutritional quality, environmental impact and costs of diets.

Quantifying global agricultural water appropriation with data derived from earth observations

Agricultural water appropriation has undergone rapid changes in recent decades, but estimates of global water appropriation have not been updated with the latest data and consistent methods. Documenting these changes is challenging given the heterogeneous water use landscape and the growing influence of human activities worldwide, and this complexity cannot be well addressed with the existing methodology, which is subject to large model uncertainties. Here, a spatial analysis and aggregated method was proposed to quantify and refine estimates of global agricultural water appropriation (GAWA) in terms of consumptive freshwater use, with data derived from Earth observations, independent of estimates from hydrological models. The results show the global water appropriation at the pixel scale, in agroecological zones and in the main water-consuming countries, including global maps of rainfed and irrigated cropland evapotranspiration (ET), net water consumption due to irrigation, natural ET and renewable freshwater resources (RFWR), and indicate that agriculture remains the largest user in terms of both water consumption and withdrawals worldwide, representing 87% of global water consumption, with approximately 60% of global freshwater withdrawals devoted to irrigation circa 2015. The percentage of withdrawals devoted to irrigation has decreased in recent decades when compared to the previous estimate of 70%. The results reveal the actual global crop consumptive use (8053.6 km3/yr) of blue and green water and the total human water consumption (8442 km3/yr), which represents the part of the water cycle affected by human intervention, mainly (95.4%) by agriculture. This study reveals that high-resolution irrigated croplands are essential for accurate estimations of water use appropriation and demonstrates that earth observation-derived data can provide a new understanding of global water use landscape. The study can support decision making in sustaining food and water security, and implementing water-adapted sustainable agricultural policies.

Influence of different LCIA methods on an exemplary scenario analysis from a process development LCA case study

Life cycle impact assessment (LCIA) methods quantify the impact of life cycle inventory data within each impact category by means of classification and characterization. This paper evaluated whether the selected LCIA method influenced the life cycle assessment (LCA) scenario analysis for decision support in process development and its possible reasons. For this study, a scenario analysis was used from a biorefinery LCA case study, as this is a key practice in process development. The analysis was investigated using various LCIA methods for the three midpoint impact categories of global warming potential (GWP, 12 LCIA methods totaling 48 subcategories), eutrophication potential (EP, 9 LCIA methods totaling 18 subcategories), and water assessment (WA, 10 LCIA methods totaling 26 subcategories). The GWP category showed consistent interpretations for the scenario analysis from different LCIA methods. The subcategory of marine EP from the two LCIA methods disagreed on the best-case scenario. Another discrepancy was identified within the three general EP indicators, where the trend of the scenario analysis was inverted in one method because of the sensitivity of a single substance (ethanol). Within the subcategories of WA, the inclusion or exclusion of hydropower water impacts changed the scenario analysis in the blue water use and total freshwater use subcategories, and the general WA indicators also disagreed on the best-case scenario. It is important to understand these influences and the reasons behind the variations for decision support in process development.

Assessment of water footprint based on estimated crop evapotranspiration for paddy, sugarcane and banana under semi-arid climate

Climate change impact has adverse effects on water use in crop production. A better crop water use indicators to decide upon the water use policies of that region or country is necessary. Water footprint indicates relationship between water use and crop yield. Rice, sugarcane and banana are the major crops which require a significant amount of water in Lalgudi block of Trichy district in Tamil Nadu. This study analyzed the total water requirement, blue and green crop evapotranspiration, blue and green crop water use and blue, green and total water footprint for paddy, sugarcane and banana in Lalgudi block. The crop water footprint estimated by using FAO56-Kc for paddy, sugarcane and banana was 2173 m3 ton-1, 304 m3/ton and 501 m3/ton respectively. And by using ClimAdj-Kc, the crop water footprint for paddy, sugarcane and banana was 2228 m3 ton-1, 307 m3/tonand 503 m3/tonrespectively. It was found that quantity of water used for producing per ton of yield was higher in paddy in comparison to banana and sugarcane.

Plant-Based Dietary Patterns for Human and Planetary Health.

The coronavirus pandemic has acted as a reset on global economies, providing us with the opportunity to build back greener and ensure global warming does not surpass 1.5 °C. It is time for developed nations to commit to red meat reduction targets and shift to plant-based dietary patterns. Transitioning to plant-based diets (PBDs) has the potential to reduce diet-related land use by 76%, diet-related greenhouse gas emissions by 49%, eutrophication by 49%, and green and blue water use by 21% and 14%, respectively, whilst garnering substantial health co-benefits. An extensive body of data from prospective cohort studies and controlled trials supports the implementation of PBDs for obesity and chronic disease prevention. The consumption of diets high in fruits, vegetables, legumes, whole grains, nuts, fish, and unsaturated vegetable oils, and low in animal products, refined grains, and added sugars are associated with a lower risk of all-cause mortality. Meat appreciation, health concerns, convenience, and expense are prominent barriers to PBDs. Strategic policy action is required to overcome these barriers and promote the implementation of healthy and sustainable PBDs.

Yield, Physiology, Fruit Quality and Water Footprint in Persian Lime (Citrus latifolia Tan.) in Response to Soil Moisture Tension in Two Phenological Stages in Campeche, México

Sixteen irrigation treatments were applied on Persian lime, based on the combination of four soil moisture tensions (SMTs) used to define the start of irrigation: −10, −35, −60, and −85 kPa during the phenological stages (PSs) of flowering (FL) and fruiting (FR). Variables evaluated were, among others: leaf water potential (Ψ), leaf stomatal conductance (gs), fruit weight (FW), fruit juice content (FJC), total soluble solids in juice (TSS), fruit yield (FY), and water footprint (WF). Greater values on the Ψ and gs variables were observed in plants subjected to SMTs of −10 and −35 kPa (p &lt; 0.05). The SMT of −85 kPa during FR produced a low FW value, while the lower SMTs in this PS increased it (p &lt; 0.05). FY was greater in the treatments including −10 kPa or −35 kPa during either of the two PSs, with the exception of those with −85 kPa in one of the stages (p &lt; 0.05). Lower FJC values were obtained at a SMT of −85 kPa in FR, and higher TSS values were observed in the two driest treatments (p &lt; 0.05). The smallest WF values were observed in the −60 kPa FL and −60 kPa FR treatment (p ≤ 0.05). Irrigation management based on the SMT significantly affected almost all the response variables evaluated. It is recommended to irrigate the crop at a SMT of −35 kPa in FL and −60 kPa in FR, the treatment in which the greatest FW, FY, and FJC values and the lowest TSS and WF values were obtained (p &lt; 0.05) and in which only 93 L of water was used by the trees to produce one kilogram of fruit (16% of the amount used in the treatment with the largest WF). The use of blue water is limited by its scarcity and high opportunity cost, an aspect that can be mitigated if blue water is used efficiently in Persian lime production systems, based on the results of this study.

Healthy beverage initiatives: A case study of scenarios for optimizing their environmental benefits on a university campus

The association between consumption of sugar sweetened beverages (SSBs) and diseases including diabetes, liver disease and dental disease is well known, yet SSBs continue to be aggressively promoted, including on university campuses. Healthy beverage initiatives (HBIs) are focused on improving health by decreasing consumption of SSBs. Some HBIs also aim to improve environmental sustainability, e.g. by substituting tap water for SSBs, including the HBI on the 10 campuses of the University of California. However, there is no study of HBIs’ potential environmental benefits. To address this knowledge gap we carried out an environmental life cycle assessment of greenhouse gas emissions, blue water use, and plastic pollution for both liquid content and container for the 940,773 liters of beverages consumed in one calendar year at the University of California, Santa Barbara. We found that climate and water impacts per liter for liquid contents of 10 SSB beverage types and the non-SSB versions of these 10 types without added sugar, were very similar and larger than that of the containers. Impacts of six container types varied widely, with climate impact highest for glass, and blue water and plastic impact highest for plastic containers, while aluminum had higher climate impact than plastic. We then evaluated the environmental benefits of 12 counterfactual HBI scenarios with different combinations of container types and liquid beverages for SSBs, non-SSBs, bottled water, and tap water. The scenario that replaced all other beverages with tap water eliminated almost all environmental impacts, while scenarios that reduced SSBs but increased beverages other than tap water took back many benefits of reduced SSBs. Our results show that to optimize potential environmental benefits, HBIs need to emphasize reducing consumption of all commercial beverages and replacing them with tap water, which will also optimize health benefits. Our methods and results will be valuable for higher education, other institutions, and communities seeking to maximize both health and environmental benefits of healthy beverage policies. • Healthy beverage initiatives (HBIs) aim to reduce sugar sweetened beverages (SSB). • We estimated climate, water and plastic impacts of beverages for 12 HBI scenarios. • Climate and water impacts per liter were greater for liquid contents than for containers. • Replacing all commercial beverages with tap water had lowest impacts. • Replacing SSBs with beverages other than tap water took back many benefits.

Integrating Blue and Green Water to Identify Matching Characteristics of Agricultural Water and Land Resources in China

The uneven distribution and spatial mismatch between water and land resources (WLR) limit the utilization efficiency of agricultural water and land resources (AWLR), and then pose a threat to food production. There is a critical need to understand their matching characteristics for strategic resource allocation decisions and management. In this study, a holistic index (RSI) derived from resource equivalency analysis (REA) was developed which contributed to examine the abundance or deficiency of agricultural water and land resources (AWLR) based on the conception of generalized water resources (including blue water and green water). Results indicate that the matching degree of AWLR was the lowest in Northeast China, North China and Gansu in Northwest China, while the highest value was in Xinjiang due to the higher blue water use. In north China, other provinces suffered water scarcity except in Jilin, Liaoning, Henan, while all provinces in south China suffered land scarcity except in Tibet and Jiangsu. Meanwhile, the matching of AWLR was not exactly consistent with the distribution pattern of precipitation. The higher proportion of green water resources was not located in southeast China with rich precipitation; it had to do with water management. Too much or little water resources can result in the increasing of blue water use. The proposed approach can be a powerful instrument to implement public policies and management strategy as an attempt to improve the utilization efficiency and enhance the optimize-allocation of AWLR.

Water Footprint of Table Grape Production Systems: A Review of South African and Global Studies

Being a water-scarce country, South Africa (SA) faces several water challenges, including drought and other effects of climate change. Therefore, there is a need to improve water-use efficiency (WUE) by accurately quantifying the water use and WUE of table grape vineyards. The objective of this review is to (i) provide an overview of water footprint (WF) studies conducted on table grape production systems in SA and globally; (ii) identify limitations in current WF assessments of table grape production systems; and (iii) establish a range of WF values for table grape production systems as an indicator of WUE and for use in decision-making regarding sustainable freshwater use. The review has demonstrated that only a limited number of detailed WF studies have been undertaken on table grapes in SA and globally. Region-specific lookup tables for quantifying blue, green and grey water use in table grape production systems are available for three table grape production regions of SA and could be used for future WF assessments. Most global studies conducted on grape WF and WUE were desktop studies and did not include actual field records from production units, nor did they distinguish between different grape types (table, raisin and wine grapes). WF values must be interpreted in context, specifically regarding the water used versus yield, quality and income, as well as the region, climatic conditions, soil characteristics, irrigation and cultivation practices. For future WF and WUE assessments, a more detailed breakdown of water use is recommended, both during the production process and postharvest.

518 Late-Breaking: Effect of Feedlot Diets on Environmental Emissions from Four Representative U.S. Feedlots and the Beef Production System

Abstract Our objective was to evaluate effects of feedlot dietary management strategies on environmental impacts and net returns of feedlot operations in the United States. Representative feedlots were simulated with the Integrated Farm System Model (IFSM 4.6; USDA-ARS, University Park, PA) to quantify baseline environmental impacts of feedlot production and full US beef cattle production systems. The simulated dietary strategies included: 10% increase in feed efficiency, use of less water intensive forages, 10% increase in byproduct inclusion, 10% improvement in water use efficiency of corn, and steam-flaking of corn. Days on feed and head finished per year were held constant for all strategies to have equal comparisons to baseline results. Dietary management strategies were individually modeled and simulated in IFSM for each feedlot operation to obtain intensities (expressed per kg gain) for greenhouse gas (GHG) emissions, fossil energy use, blue water consumption, and reactive nitrogen loss. Feedlot operations were then linked with cow-calf, stocker, and backgrounding operations to estimate environmental intensities (expressed per kg CW) for full cattle production systems. Improving feed efficiency had the greatest effect on reducing carbon emission intensities (6%), energy use intensity (8%), blue water use intensity (9%), and reactive N loss intensity (4%) for feedlot operations. Increasing corn byproduct inclusion resulted in 9% reduction in blue water use intensity. However, byproduct inclusion increased reactive N loss intensity by 11% as a result of greater protein concentrations in the diet. Switching from rolled corn to steam flaked corn increased energy use intensity by 9%, but little to no changes (1% increase to 3% reduction) were observed for other environmental intensities. Improved feed efficiency was the most effective strategy to reduce environmental footprints of beef cattle production (1 to 2% reductions). Overall, feedlot dietary strategies were less pronounced for the full beef production system compared with feedlot results.

Assessment of Crop Water Footprint for Different Varieties of Groundnut (Arachis hypogaea)

Background: Water Footprint is a recently used indicator which helps to reduce water depletion and alleviate water stress in areas of drought and proper crop cultivation. Hence a study was taken up to assess the crop water footprint of different groundnut varieties namely TMV 7, VRI 2, VRI 3, VRI Gn 5, VRI Gn 6, CO 3, CO Gn 4, ALR 3 and TMV Gn 13 cultivated during Kharif and Rabi seasons at Tiruchirapalli district of Tamil Nadu. Methods: The total water requirement, blue and green crop evapotranspiration, blue and green crop water use and total water footprint for different varieties of groundnut were estimated using CROPWAT 8.0 Windows. A comparison was made between the water footprint of groundnut varieties and the strategies to reduce water footprint is presented. Result: The total water footprint for groundnut varieties ranged from 2603 to 4889 m3 ton-1 (CV of 26%) during kharif season, while it was ranged from 1465 to 2470 m3 ton-1 (CV of 18%) during rabi season. It was found that in all groundnut varieties the blue water footprint is higher than the green water footprint, while VRI Gn 5 variety had minimum total water footprint. It was concluded that, the groundnut production is affected by different levels of blue water stress which requires effective irrigation practices and water management strategies to enhance the crop production.

Impact of a College Course on the Sustainability of Student Diets in Terms of the Planetary Boundaries for Climate Change and Land, Water, Nitrogen and Phosphorus Use

While it is widely acknowledged that shifts in diet could play a large role in mitigating climate change with important health co-benefits, knowledge on how to accomplish these shifts is lacking. Our previous study showed a statistically significant reduction in the dietary carbon footprint of students who had completed a college course on the connections between food and the environment compared to a control group enrolled in an unrelated course. An extension of the previous study, this research evaluates the sustainability of female and male diets in both the intervention and control groups from baseline to follow up with respect to the following planetary boundaries: greenhouse gases, land use, water use, nitrogen loss, and phosphorus use. In addition, a 50-point modified Alternative Healthy Eating Index was calculated at baseline and follow up for all students. Female students enrolled in the intervention course reported diets with statistically significant reductions in their footprints from baseline to follow up for greenhouse gases (p = 0.011), land use (p = 0.012), and phosphorus (p = 0.045), and the female diets were statistically different from the control groups for those three boundaries. For water use, female diets increased in footprint from baseline to follow up due to an increase in vegetable intake. Males enrolled in the intervention showed similar trends (reductions in footprints for greenhouse gases, land use, and phosphorus use and an increase in blue water use), but differences were not statistically significant, partially due to the smaller number of male respondents. Student dietary footprints are compared to a per capita limit allowable for food according to the planetary boundaries concept. For all of the planetary boundaries except blue water use, the student dietary footprints were well above the per capita boundary for food-related sources.

Decadal gross level assessment of green and blue consumptive water use over Indian agro-ecosystems

ABSTRACT Assessment of consumptive water use (CWU) and water productivity at the regional scale is important to diagnose vulnerable zones to improve water use efficiencies in cropland to achieve the sustainable development goal 6.0 prescribed by the United Nations. The present study was carried out to segregate and quantify CWU into agricultural green (CWUg) and blue (CWUb) water use and water productivity (AWP) on seasonal, annual, and decadal (2009–2018) scales over the Indian region using satellite remote-sensing data from geostationary and polar-orbiting platforms. A logical algorithm was used to determine partitioned water use from a combination of satellite-based estimates of key variables such as agricultural water demand (AWD), actual evapotranspiration (ETa), and effective rainfall (ER). Satellite-based estimates of CWU were evaluated with respect to ground reference that showed underestimation of the order of 15–32% but with a strong Pearson’s correlation coefficient (r = 0.80–0.99) and coefficient of determination (R 2 = 0.64–0.98). The reasons for this difference and uncertainties in satellite-based inputs have been explained. The decadal mean of CWU at annual scale showed wide spatial variation over India with 84% and 16% share of CWUg and CWUb, respectively, in kharif season and 27% and 73%, respectively, in rabi season. A non-significant increasing trend in CWUg,kharif (0.57%) and a decreasing trend in CWUb,kharif (–5.18%), CWUg,rabi (–2.81%), and CWUb,rabi (–1.77%) were observed over 10 years. A decreasing trend in green AWP (AWPg) (–0.18%) in kharif season reveals a lack of sustainable adoption of green water management practices while a significantly increasing trend in AWPb (2.65%) in rabi season reveals sustainable adoption of efficient irrigation management practices over 10 years. These long-term estimates would help in smoothing out trade-offs of water use versus water productivity, reducing the vulnerability and aiding in decision-making for water savings, controlled water allocation, strategic policy formulations for water, and food security especially through sustainable management practices in rainfed agriculture.

Environmental assessment of United States dairy farms

Dairy farms in the United States are diverse and although regional dairy production and farm strategy has been evaluated for environmental impact, a comprehensive national assessment is important to define national priorities for sustainable intensification. We estimated important environmental footprints of dairy production using process-level simulation and cradle-to-farm gate life cycle assessment. Dairy farms representing the sizes and management practices found in six regions were simulated with the Integrated Farm System Model (IFSM). Regional and national environmental footprints were determined as an average of all simulated farms weighted by the portion of milk contributed by each to the total. Nationally, dairy farms were found to emit 99,000 ± 8480 Gg CO2e of greenhouse gas (GHG), equivalent to 1.5% of the estimated U.S. total GHG emission, with a commodity-based intensity of 1.01 ± 0.09 kg CO2e/kg of fat and protein corrected milk (FPCM) produced. Fossil energy use was 242,700 ± 38,400 TJ, 0.3% of the U.S. total, or 2.48 ± 0.39 MJ/kg FPCM. Blue (non-precipitation) water use was 11,600 ± 2480 Tg, roughly 3.0% of the estimated U.S. total freshwater withdraw, with an intensity of 119 ± 25 kg/kg FPCM. While these environmental footprints represent a small portion of the respective national inventories, the dairy industry's contribution to reactive nitrogen (N) losses appears to be considerably greater. Losses of reactive N were estimated at 970 ± 133 Gg, with an intensity of 9.92 ± 1.36 g/kg FPCM where 66% of the total was in the form of ammonia (NH3). Although there are no national estimates of total reactive N loss, dairy farms were found to contribute 19–24% of national inventories of NH3 emissions. While strategies are available to reduce NH3 emissions, finding economical and sustainable solutions that do not result in pollution swapping remains a challenge for the dairy industry.

Understanding the trends in Denmark's global food trade-related greenhouse gas and resource footprint

Food production is a major driver of global warming, water scarcity and biodiversity loss. Denmark has set ambitious targets to lower its territorial carbon emissions in the next decades. In 2019, the Danish Agriculture and Food Council announced a strategy to make Denmark's food production systems climate-neutral by 2050. Therefore, detailed information concerning Denmark's food consumption's environmental impacts is required to implement effective climate mitigation and resource conservation policies that lead to positive local to global results. Using an environmentally extended multi-regional input-output (EE MRIO) analysis and the EXIOBASE v3.4 database, we evaluate Denmark's global food-related consumption-based (CB) greenhouse gas emissions (GHG) and resource (land and water use) accounts from 1995 to 2014. Although Denmark's CB food-related blue water use remained relatively stable during the studied period, its food-related CB GHG emissions (excluding land-use change emissions) decreased continuously by 30%. Also, Denmark's cropland and grassland footprints for food declined by 16% (3555 km2) and 27% (621 km2), respectively. Almost two-fifths of Denmark's food consumption was produced abroad in 2014, corresponding to 51% of Denmark's food-related CB GHG emissions and land use apiece and 84% of its food-related blue water use. Whereas animal-based foods accounted for the largest share of Denmark's food-related CB GHG emissions, plant-based diets were responsible for the bulk of Denmark's CB land and blue water use. Dietary changes towards plant-based foods are essential to mitigating Denmark's food-related climate impacts. We recommend that Denmark transfers its sustainable food production technologies to its pollution-and-resource intensive food-exporting trade partners to enhance global climate change mitigation and resource use efficiency.

Agricultural infrastructure: The forgotten key driving force of crop-related water footprints and virtual water flows in China

Here we identified and evaluated the strengths and spatio-temporal heterogeneities in 12 main socio-economic driving factors of water footprints and inter-provincial virtual water flows related to three staple crops (rice, wheat, and maize) within mainland China for 2000–2017, in consideration of the infrastructure related to irrigation, agricultural electricity and road for the first time. The irrigation, agricultural electricity, and road infrastructures in China expanded by 33.8, 4.5, and 2.4 folds, respectively, throughout the course of this study. The results show that irrigation infrastructure in water-scarce regions was the most critical driver for the effective reduction of the water footprint per unit mass of crops, particularly the blue water footprints (i.e. increasing water efficiency). As the irrigation infrastructure per unit area doubled for 2000–2008, blue water use efficiency and total blue water consumption decreased by 58% and 71%, respectively. However, the development of irrigation infrastructure has led to a larger total water footprint in crop production. Agricultural electricity and road infrastructures had increasing effects on provincial virtual water export, with varied corresponding driving strengths across spaces. The visible effects of agricultural infrastructure on regional water productivity, water consumption, and virtual water patterns should not be neglected. This analysis suggests that investments in agricultural infrastructure should consider the spatio-temporal heterogeneity of these infrastructures on local water productivity and water consumption in addition to the economic benefits.

A high-resolution assessment of climate change impact on water footprints of cereal production in India

Water footprint (WF), a comprehensive indicator of water resources appropriation, has evolved as an efficient tool to improve the management and sustainability of water resources. This study quantifies the blue and green WF of major cereals crops in India using high resolution soil and climatic datasets. A comprehensive modelling framework, consisting of Evapotranspiration based Irrigation Requirement (ETIR) tool, was developed for WF assessment. For assessing climate change impact on WF, multi-model ensemble climate change scenarios were generated using the hybrid-delta ensemble method for RCP4.5 and RCP6.0 and future period of 2030s and 2050s. The total WF of the cereal crops are projected to change in the range of − 3.2 to 6.3% under different RCPs in future periods. Although, the national level green and blue WF is projected to change marginally, distinct trends were observed for Kharif (rainy season—June to September) and rabi (winter season—October to February) crops. The blue WF of paddy is likely to decrease by 9.6%, while for wheat it may increase by 4.4% under RCP4.5 during 2050s. The green WF of rabi crops viz. wheat and maize is likely to increase in the range of 20.0 to 24.1% and 9.9 to 16.2%, respectively. This study provides insights into the influences of climate change on future water footprints of crop production and puts forth regional strategies for future water resource management. In view of future variability in the WFs, a water footprint-based optimization for relocation of crop cultivation areas with the aim of minimising the blue water use would be possible management alternative.