Blue, green, and grey water footprints assessment for paddy irrigation-drainage system

Water footprint of irrigated rice in the state of Rio Grande do Sul, 2019/2020 crop

Agricultural production is the practice that uses the most water on the planet, especially the irrigated agriculture, which represents a large part of this demand. As well as the quantitative issue, adequate quality is essential to meet the demands of the crop and its return to the water sources, in a way that does not cause damage to the environment. To measure this consumption, the expression "water footprint" emerged. The water footprint seeks to quantify the demand for water incorporated into products. This paper aims to determine the amount of water used to produce irrigated rice in six rice growing regions in the state of Rio Grande do Sul (RS), in the 2019/2020 crop. The mentioned regions are represented the municipalities of Uruguaiana (West Border), Dom Pedrito (Campanha), Santa Maria (Central Region), Camaquã (Internal Coastal Plain), Porto Alegre (External Coastal Plain), and Rio Grande (South Zone). Climate data from the analyzed regions, during the plant cycle, and productivity values in the crop in question were used. Values of 1187 m3 t-1 were found for WB, 1347 m3 t-1 for CA, 1058 m3 t-1 for CR, 783 m3 t-1 for ICP, 1115 m3 t-1 for ECP, and 1066 m3 t-1 for SZ. For the state of Rio Grande do Sul, an average water footprint was obtained in the 2019/2020 crop of 1093 m3 t-1.

Sustainability assessment on paddy-upland crop rotations by carbon, nitrogen and water footprint integrated analysis: A field scale investigation

Nutrients of carbon, nitrogen and water of farmland ecosystem are essential foundation to guarantee crop production, but also environmental flows associated greenhouse gas (GHG), reactive nitrogen (Nr) releases, and water consumption. Their flow characteristics serve as a crucial starting point for creating efficient management practices and mitigation measures. Therefore, the objectives of this study are to quantify the carbon footprint (CF), nitrogen footprint (NF), water footprint (WF), and comprehensive environmental footprint (ComF) of six paddy-upland rotation systems, including fallow-paddy rice (FA-PR), Chinese milk vetch-paddy rice (CMV-PR), wheat-paddy rice (WH-PR), rapeseed-paddy rice (RA-PR), green forage wheat-paddy rice (WF-PR), and vicia faba bean-paddy rice (FB-PR), as well as to analysis their relationships and define driving factors. Results showed that the lowest area-scaled CF of 3.74 t CO₂-eq ha^-1 were observed in the CMV-PR rotation, which were 41% lower than that for WH-PR (the highest CF, 9.13 t CO₂-eq ha^-1) when soil carbon change was taken into account. It is of importance that soil carbon sequestration in CMV-PR rotation could offset up to around 57% of its CF, while the WH-PR rotation only offset 25%. The RA-PR rotation had the highest area-scaled NF and WF, which was 1.8 and 1.9 times greater than those of the lowest rotation in FA-PR. In terms of comprehensive environmental effects, the six rotation systems showed the order of FA-PR < CMV-PR < FB-PR < RA-PR < WF-PR < WH-PR, with NH₃ volatilization accounting 60.7%-66.7% and blue-green WF for 17.5%-26.6% of the total. Therefore, priority should be given to optimizing N fertilizer application and water consumption for paddy-upland rotation systems. The study also suggested that appropriate inter-annual adjustment of rotation system could contribute to achieving GHG mitigations and Nr losses.

Effects of paddy irrigation-drainage system on water quality and productivity of small rivers in the Himi region of Toyama, Central Japan

The aim of this study was to clarify the impact of differences between historical and recently introduced irrigation and drainage management systems on water quality in the rivers around paddy fields. We investigated the seasonal variation in nutrients concentration and dissolved organic carbon (DOC) components in single- (used for intake only) and dual-purpose (used for both intake and drainage) channels during a 4-year period in the Himi region of Toyama, Central Japan. The system of dual-purpose channel has traditionally been used in the region of this study. A total of 197 three-dimensional excitation-emission matrix (3DEEM) fluorescence spectra of DOM in waters were applied for the parallel factor analysis (PARAFAC) modeling. Based on the 3DEEM and PARAFAC, the abundance of terrestrial humic-like components in the dual-purpose channel was significantly higher than that in the single-purpose channel. The even long-chain n-fatty acids derived associated with rice cropping in sediments of the dual-purpose channels were 22-30-fold higher than that of the single-purpose channel. In addition, the turbidity values of the river waters had significantly positive linear correlations with concentrations of K⁺, DOC, and humic-like components. These observations indicate that the dissolved nutrient concentrations in the river water were higher in the dual-purpose channel compared to those of the single-purpose channel, which may be supplied by leaching from the inflow of soil particles from the paddy fields. During the mid-irrigation period, the quantity of epiphytic chlorophyll a on artificial substrate tiles in the dual-purpose channel were 3.1-4.1-fold higher than that in the single-purpose channel. This study clear that the input of paddy drainage during the irrigation season significantly changes the DOC components in river waters and irrigation management is strongly linked to the primary production in agricultural channels. Therefore, it is important to consider the impact of the introduction of different irrigation and drainage management systems on water quality and productivity in order to maintain the riverine ecosystems around rice paddies, which are based on historical water use systems.

The impact of irrigation modes on agricultural water-energy‑carbon nexus

Despite the tremendous contribution of irrigated agriculture in addressing global food security, there is still confusion for farmers and governments about the choice of irrigation mode owing to the drastic environmental impacts of irrigation, including water shortage, energy crisis, and global warming. Exploring the agricultural water-energy‑carbon (WEC) nexus under different irrigation modes helps to accomplish the multi-objective of water & energy saving and carbon emission reduction. In this paper, a conceptual framework was nominated to evaluate the water & energy consumption and carbon emissions for winter wheat irrigation at township level and quantitatively discuss the complex interaction by the coupling coordination degree (CCD) of the WEC system under different irrigation modes in Henan Province, China. We discovered that irrigation modes profoundly affect water and energy consumption and carbon emissions in agriculture, as well as the spatial distribution of CCD from WEC system. Townships under irrigation mode with diversion and irrigation projects as the primary method (WDI) clustered together in the north and east with highest water consumption and carbon emissions, while townships under irrigation mode with rain-fed agriculture as the primary method (PI) accumulated in the west and south with lower water consumption and carbon emissions. Meanwhile, the CCD of the WEC nexus system was in basic coordination (0.40) and showed an unbalanced spatial distribution pattern with high in the southeast and low in the northwest. By comparing four irrigation modes, the coupling level of the WEC nexus system under irrigation mode with groundwater irrigation as the primary method (GI) was better and PI mode was the least ideal. This study helps to further understand agricultural WEC nexus under different irrigation modes and provide references for local governments in selecting appropriate irrigation modes to realize water-energy saving and carbon emission reduction in agricultural activities.

Estimation of the water footprint of kiwifruit: in the areas transferred from hazelnut to kiwi

Agriculture is the largest consumer of freshwater and plays a critical role in addressing global water scarcity. While numerous studies have focused on the water footprint (WF) of various agricultural products, little attention has been paid to changing cropping patterns and their impact on WF. Here, we investigate the impact of conversion from hazelnut fields to kiwi orchards on green, blue, and gray WF between 2010 and 2021 in Ordu, Turkey. Our results show a total increase of 803,901 tons WF for all green, blue, and gray WF. Compared to the previous situation, changing the agricultural product and growing kiwifruit on previously established hazelnut fields increases green WF by 372,106 tons and blue WF by 334,167 tons. Thus, the change of cultivation pattern could significantly contribute to the water scarcity in the area, and at the same time, the increase in WF. Although kiwi cultivation might be advantageous economically, this economic benefit might be an ecological disadvantage as kiwi production is highly dependent on limited blue water resources. Therefore, it is suggested to further promote the rain-fed product, the hazelnut.

Adherence to the Mediterranean diet and its association with environmental footprints among women of childbearing age in the United Arab Emirates

PURPOSE

To examine the association of adherence to the Mediterranean Diet (MD) with Environmental Footprints (EFPs) among women of childbearing age in the United Arab Emirates (UAE).

METHODS

Data belonging to a nationally representative sample of 482 women (19-50 years) were derived from a previous survey in the UAE. In face-to-face interviews, participants completed questionnaires addressing sociodemographic, physical activity, and dietary intake characteristics; the latter assessed using a multiple pass 24-h recall. The composite Mediterranean (c-MED) index was used to examine the adherence to the MD. Metrics for the EFPs (water use, energy use, and GHG emissions) were calculated using Life Cycle Analyses. Descriptive statistics and linear regressions were used in data analysis.

RESULTS

In the study sample, the distribution of the c-MED scores was skewed to the right, indicating a low adherence to the MD. The lowest contributions to the total c-MED score were observed for legumes (2.9%) and olive oil (1.8%). The EFPs associated with food consumption per 1000 kcal were: water use: 1256.89 ± 544.95 L/day; energy use: 18.01 ± 7.85 MJ/day, and GHG: 2.46 ± 1.46 kg CO_{2 eq}/day. After adjustment for age, energy intake, and potential confounders, being adherent to the MD was associated with 540.57 [95% CI (- 726.6; - 354.54)] units decrease in water use and 0.94 units decrease in GHG emissions [95% CI (- 1.45; - 0.43)].

CONCLUSIONS

The findings of this study revealed an inverse association between adherence to the MD and EFPs. As such, the MD may represent a promising dietary strategy to improve health outcomes and reduce the environmental impact. Public health programs addressing the low adherence to the MD among women of childbearing age in the UAE are warranted.