The emergy ecological footprint for small fish farm in China

Mariculture, especially cage aquaculture remains a growing, vibrant and important production sector for high protein food in coastal regions in China. A quantitative evaluation of the mariculture system is an essential step to documenting its’ sustainability. The method of emergy ecological footprint is applied to evaluate the environmental sustainability of an offshore small fish farm (Great Marine fish farm, GMFF) in the East China Sea. All input needed to support fish farming were accounted and converted into biological space, to estimate the natural capital demand for the rearing process in terms of global hectares. The emergy ecological footprint of GMFF was 1953.19 ha, meaning that nearly 2000 ha of ecologically productive lands were needed to support the fish framing. The largest component of emergy ecological footprint was forage (1183.64 ha), which took up 60.60% of the total footprint; the second and third largest footprint components were fingerlings and fuel. In a word, emergy ecological footprint can serve as a practical and meaningful tool for comparing and monitoring the environmental impact of fish farming. The strong dependence of external contributions of exploiting the wild fish resources affects strongly the level of environmental sustainability of fish farming.     

Interregional bio-physical connections—A ‘footprint family’ analysis of Israel’s beef supply system

The need to advance bio-physical accounting as a base for sustainability assessment has been acknowledged and advanced in recent years. One approach highly relevant to the 21st century global reality is the ‘Footprint’—Ecological, Land, Water and Carbon. While each has merits and limitations, the potential to bring all together under the title of the ‘Footprint Family’ is emerging. This paper embraces a footprint family approach to analyze beef consumption in the state of Israel over a decade (1999–2010) and explore some tradeoffs between different biophysical components. The research results reveal that on average a tonne of beef consumed in Israel, reflecting a mixture of sources of supply from all over the world requires 9.5 ha of land and 10,000 m³ of water, mostly for grazing in Latin America (in Brazil and Argentina) but also for growing feed in the U.S and the E.U. Enteric fermentation, manure management, farm operations, shipping and slaughtering generate approximately 19.7 t of CO₂e and the above can be integrated into an ecological footprint figure of approximately 6 global hectares. The paper also demonstrates the utility of inter-regional biophysical accounting at the detailed commodity level. Inter-regional accounting identifies the geographic locations that contribute resources to, and are affected by, the production of specific consumption products. Comprehensive interregional biophysical accounting can be used to generate a better understanding of the complex ecological impacts associated with most consumption products, and the implications of the relationship between these impacts for sustainability.     

Quantification of the water,energy and carbon footprints of wastewater treatment plants in China considering a water–energy nexus perspective

Water and energy are closely connected and both are very important for human development. Wastewater treatment plants (WWTPs) are central to water–energy interactions as they consume energy to remove pollutants and thus reduce the human gray water footprint on the natural water environment. In this work, we quantified energy consumption in 9 different WWTPs in south China, with different treatment processes, objects, and capacities. The energy intensity in most of these WWTPs is in the range of 0.4–0.5 kWh/m³ in 2014. Footprint methodologies were used in this paper to provide insight into the environmental changes that result from WWTPs. A new indicator “gray water footprint reduction” is proposed based on the notion of gray water footprint to better assess the role of WWTPs in reducing human impacts on water resources. We find that higher capacity and appropriate technology of the WWTPs will result in higher gray water footprint reduction. On average, 6.78 m³ gray water footprint is reduced when 1 m³ domestic sewage is treated in WWTPs in China. 13.38 L freshwater are required to produce the 0.4 kWh electrical input needed for treating 1 m³ domestic wastewater, and 0.23 kg CO₂ is emitted during this process. The wastewater characteristics, treatment technologies as well as management systems have a major impact on the efficiency of energy utilization in reducing gray water footprint via these WWTPs. The additional climate impact associated with wastewater treatment should be considered in China due to the enormous annual wastewater discharge. Policy suggestions are provided based on results in this work and the features of China's energy and water distribution.     

Expanding ecological appropriation approach: Solar space method and a case study in Yangzhou city,East China

In this paper, the authors made an attempt to measure appropriation of ecosystems more reasonably and effectively based on examining the advantages and disadvantages of emergy analysis and ecological footprint. By combining emergy analysis with ecological footprint (EF) in terms of spatial equivalent of energy productivity, a new method of solar space (SS) and its calculating framework was proposed, and some necessary parameters for this method of analysis were calculated. A case study was followed under this calculating framework for Yangzhou city, Jiangsu province, Eastern China, using the data of the year 2000. The main results are as follows: (1) The ecological space in Yangzhou city includes earth surface space and solar space, and their demands were bigger than their supply. In the year of 2000, the earth surface space had an absolute deficit of 2.3063E?02 Ga-ha per capita (global hectares), and the solar space had an absolute deficit of 1.4944E?04 Sa-ha per capita (solar hectares). (2) There was a relative ecological deficit of 3.68% in earth surface space, and that of 154.86% in solar space. (3) Only freshwater areas and built-up areas were in a state of surplus, and there was a relative ecological surplus of 82.66% for freshwater areas, being greater than that for built-up areas. (4) The ranking of absolute ecological deficit in a descending order was as follows: solar space > arable land > pasture > forest > marine area > garden land, while the relative ecological deficit was the following: solar space > pasture land > forest land > arable land > garden land, except marine areas.A qualitative comparison of methodology was made between solar space method and ecological footprint according to their capability to describe the temporal-spatial characteristics of ecosystems appropriation. Moreover, a quantitative comparison was also conducted to show their differences in applicability to the assessment of ecosystems appropriation. It was shown that the calculating results from solar space method were bigger than that from ecological footprint because the former supplemented additional items of appropriation omitted by the later and included some new items of indirect appropriation that were excluded by the later. It is found that the new measure of solar space operates well as an indicator of the city's appropriation to ecosystems.     

Loss of aboveground forest biomass and landscape biomass variability in Missouri,US

Disturbance regimes and forests have changed over time in the eastern United States. We examined effects of historical disturbance (circa 1813 to 1850) compared to current disturbance (circa 2004 to 2008) on aboveground, live tree biomass (for trees with diameters ≥13 cm) and landscape variation of biomass in forests of the Ozarks and Plains landscapes in Missouri, USA. We simulated 10,000 one-hectare plots using random diameters generated from parameters of diameter distributions limited to diameters ≥13 cm and random densities generated from density estimates. Area-weighted mean biomass density (Mg/ha) for historical forests averaged 116 Mg/ha, ranging from 54 Mg/ha to 357 Mg/ha by small scale ecological subsections within Missouri landscapes. Area-weighted mean biomass density for current forests averaged 82 Mg/ha, ranging from 66 Mg/ha to 144 Mg/ha by ecological subsection for currently forested land. Biomass density of current forest was greater than historical biomass density for only 2 of 23 ecological subsections. Current carbon sequestration of 292 TgC on 7 million ha of forested land is less than half of the estimated historical total carbon sequestration of 693 TgC on 12 million ha. Cumulative tree cutting disturbances over time have produced forests that have less aboveground tree biomass and are uniform in biomass compared to estimates of historical biomass, which varied across Missouri landscapes. With continued relatively low rates of forest disturbance, current biomass per ha will likely increase to historical levels as the most competitive trees become larger in size and mean number of trees per ha decreases due to competition and self-thinning. Restoration of large diameter structure and forested extent of upland woodlands and floodplain forests could fulfill multiple conservation objectives, including carbon sequestration.     

The consideration of time step in calculating grey water footprints of agricultural cropping systems

A water footprint considers both the water volumes involved in production processes and the resulting waste water generated. The grey water (GW) footprint represents the volume of fresh water required to assimilate pollutants to acceptable concentrations—a concept proposed by the water footprint network—but it faces several difficulties when applied to agricultural production systems. Crop production cannot be fully controlled and it is weather-dependent, which greatly affects the year-to-year GW calculations.In this study, we examined the effect of time step on the calculation of annual GW footprints by utilizing 30 years of daily average nitrate-nitrogen (NO₃-N) concentrations in drainage water (both leachate and runoff water derived from a process-based model) from corn and soybean production systems. For each crop year, the volume of water required to assimilate NO₃-N to an acceptable threshold concentration (i.e. <10 mg L⁻¹) was calculated over different time steps (daily, weekly, monthly, seasonally and yearly), and each case was summed to an annual GW value. Daily average NO₃-N concentrations in the effluent water were generally below the acceptable threshold concentrations, with intermittent exceedances. Thus, the fields often provided their own ‘dilution’ water, and annual average concentrations were only 2.0 mg L⁻¹ and 0.4 mg L⁻¹ for corn and soybean, respectively.The GW footprint varied significantly when calculated for different time steps. The greatest annual footprint occurred when calculated daily (shortest time step). The GW footprint for corn ranged from 2.7 × 10³ m³ ha⁻¹, or 2700 mm of water, when estimated daily to zero for the yearly time step. For soybean it ranged from 0.5 × 10³ m³ ha⁻¹, or 500 mm of water, to zero. The GW footprint results are therefore highly dependent on the time step of calculation. The effect of this issue extends beyond crop production as it is exported and amplified through feed rations to affect the GW footprint from animal production. To be able to reconcile these problems, the GW calculation pathways should be reconsidered and standardized.     

The water footprint of the EU for different diets

In this paper, the EU28 (EU27 and Croatia) water footprint of consumption (WF_cons) for different diets is analysed: the current diet (REF, period 1996–2005), a healthy diet (DGE), a vegetarian (VEG) and combined (COM) diet. By far the largest fraction of the total WF_cons (4815 lcd) relates to the consumption of edible agricultural goods (84%). The average EU28 diet is characterised by a too high energy intake and a too high ratio of animal to vegetal protein intake. For a healthy diet, the intake of some product groups should be reduced (sugar, crop oils, meat and animal fats) and of other product groups increased (vegetables and fruit). Especially the consumption of animal products accounts for high WF amounts. The three alternative diets result in a substantial reduction (−974 lcd or −23% for DGE, −1292 lcd or −30% for COM, −1611 lcd or −38% for VEG) of the WF_cons for agricultural products with respect to the existing situation (REF, 4265 lcd). The reduction in meat intake contributes most to the WF reduction. Each of the specific WF components (green, blue and grey) shows a reduction similar to the observed reduction in the total WF_cons. Regarding the total WF_cons (green, blue and grey WF_cons) as well as the WF_cons without the grey WF component (green + blue WF_cons) for agricultural products, the EU28 shifts from net virtual water (VW) importer for the REF and DGE diets to net exporter for the COM and VEG diets.     

Identifying potential restoration areas of freshwater wetlands in a river delta

Identification of potential restoration areas is significant and important for implementing a sustainable restoration project and maintaining the ecosystem integrity. We established an eco-hydrological approach to identify potential restoration areas of freshwater wetlands that should and can be restored. Our eco-hydrological method identifies potential restoration areas from three dimensions, namely, transverse, longitudinal and vertical directions. Based on transfer matrix analysis between freshwater wetland and other land cover types and bird habitat suitability assessment, we identified the areas that should be restored under the 1989 and 2000 goals were 36,112 ha and 37,230 ha, respectively. Based on hydrological connectivity and balance between ecological water supply (EWS) and ecological water requirements (EWRs), the area can be restored under the 1989 and 2000 goals were 31,165 ha and 33,963 ha, respectively. The approach and results of this study can help in future restoration efforts in the Yellow River Delta and other similar coastal wetlands.     

Impacts of human activity on environment in the high-cold pasturing area: A case of Gannan pasturing area

Identifying the specific forces driving environmental impact is a hot topic in the field of sustainable development in the pasturing area. In the paper, the ecological footprint was taken as the index of environmental impact, and a series of index like population quality, prosperous, using intensity, livelihood tactics are considered as the main human factors. Using the STIRPAT model and temporal series data from 1980 to 2007, the author analyzes the effects of the human driving forces of environmental impact.
The ecological footprint method presents a simple framework for national natural capital accounting, and it has been used as a comprehensive index of human activity impact, which indirectly reflect human activity’s pressure on the environment. Our analyses showed that the ecological footprint increased from 238736.9 to 877716.1 ha and per capital ecological footprint also increased from 0.854 to 1.961 ha/per during 1980–2007 in Gannan pasturing area. However, in the meantime, the ecological footprint intensity was inclined from 25.396 to 3.025 ha/ten thousand yuan.
With a view of dismantling the human driving forces of ecological footprint, the modified IPAT-called STIRPAT has been employed as a common analytic framework. Our analyses showed that population quantity and using intensity was a major driver of ecological footprint, their coefficients were greater than 1.0 in model (1); In addition, promoting the prosperous lever and the primary industry proportion, the impact of environment will be increased, but their coefficients are less than 1.0 in model (1). At the same time, the technological eco-efficiency of sample regions was discussed in details, the range ability of the technological eco-efficiency was wider, and 15 years went beyond the average level, but the other was less than the average level. Another important finding in the empirical study is that there are some evidences of an environmental Kuznets curve for ecological footprint within the range of calculated data. Some potential improvements in some further researches and suggestions to alleviate the environment pressure, and it is put forward in the last section.     

Carbon footprints of rice production in five typical rice districts in China

Five provinces located in the five main rice-growing regions in China were selected as study areas, which were Jiangsu, Heilongjiang, Sichuan, Guangdong and Hunan province respectively in the middle and lower reaches of the Yangtze River, northern, southwest, southern and central rice districts. Carbon footprints of rice production in these five provinces were calculated through the life cycle assessment method using governmental statistical data, industrial standards and relevant technical data separately. Material and energy consumptions were estimated, key stages of energy consumptions and carbon emissions were identified as well. Moreover, improving measurements had been suggested correspondingly. The results indicated that: the energy consumptions of rice production in these five provinces ranked as following (high to low): Guangdong, Heilongjiang, Hunan, Sichuan and Jiangsu. The carbon footprints of rice production were 2504.20 kg carbon dioxide equation per ton rice (kgCO₂-eq./t) (Guangdong province), 2326.47 kgCO₂-eq./t (Hunan province), 1889.97 kgCO₂-eq./t (Heilongjiang province), 1538.90 kgCO₂-eq./t (Sichuan province) and 1344.92 kgCO₂-eq./t (Jiangsu province) respectively. Reducing the quantities of urea and using the intermittent irrigation method could decrease energy consumption as well as carbon footprint.     

Population health risk due to dietary intake of toxic heavy metals from Spinacia oleracea harvested from soils collected in and around Tshwane,South Africa

In order to assess the possible health risk associated with the consumption of vegetables harvested from waste dump sites, trace metal levels in Spinacia oleracea planted in soils collected from waste dump sites were investigated. Soil samples from different waste dump sites and mining areas were collected and placed in different pots. Seedlings of S. oleracea were introduced into the pots, harvested after 3 months and analysed for trace metal contents using ICP-MS. From the leaves of the plants, the concentration of Fe was found to be significantly higher than all other trace metals (p < 0.05). The trend in trace metal accumulation from the leaves was in the order Fe > Mn > Zn > Pb > Cu > Cr > Ni > Cd. A significantly different concentration of trace metals in the plant was noticed from different soils in different pots used (p < 0.05). Trace metal concentration from plant parts showed roots > leaves > stem. The risk to human health indicated as Hazard Quotient (HQ) was highest for Zn followed by Cu from all the plant parts. The HQ result showed that humans might be at risk if they consume spinach from these waste dump sites. From the study it was concluded that harvesting/consuming spinach from soil around a waste dump site may be extremely dangerous.     

Digestive capacities allow the Mexican long-nosed bat (Leptonycteris nivalis) to live in cold environments

Digestive capabilities of nectar-feeding vertebrates to assimilate sugars affect their ability to acquire and store energy and could determine the minimal temperatures at which these animals can survive. Here, we described the sugar digestive capability of Leptonycteris nivalis and related it with its capacity to live in cold environments. We measured the enzymatic activity, food intake rate and changes in body mass of bats feeding at four different sucrose concentrations (from 5 to 35% wt./vol.). Additionally, we used a mathematical model to predict food intake and compared it with the food intake of bats. L. nivalis was able to obtain ~ 111.3 kJ of energy regardless of the sugar concentration of their food. Also, bats gained ~ 2.57 g of mass during the experimental trials and this gain was independent of sugar concentration. The affinity (1 / K_m) of sucrase (EC 3.2.1.48) was one order of magnitude higher relative to that reported for its sister species Leptonycteris yerbabuenae (0.250 and 0.0189 mmol^? 1 L, respectively), allowing this species to have a higher energy intake rate. We propose that the high ability to acquire energy conferred L. nivalis the faculty to invade cold environments, avoiding in this way the ecological competition with its sympatric species L. yerbabuenae.     

Emergy synthesis of a combined food and energy production system compared to a conventional wheat (Triticum aestivum) production system

It is a major challenge to produce food and energy sustainably for the ever increasing world population as today's conventional food production and energy needs are met by the fossil based resources, causing enormous environmental load. A novel, combined food and energy (CFE) agro-ecosystem, was designed for sustainable production of food, fodder and energy without chemical inputs (fertiliser, herbicide and fungicide). The objective was an emergy synthesis of the CFE system compared to a conventional wheat (Triticum aestivum) production system to assess resource use efficiency. The emergy indices, used to assess the environmental performance and sustainability, exhibited contrasting differences between the two production systems in terms of outputs (Y), total emergy use, solar transformity, relative use of local renewable resources, environmental loading ratio (ELR), emergy yield ratio (EYR) and emergy sustainability index (ESI). The Y in the CFE consisted of grain, straw, fodder and woodchip production of 4020, 3580, 6100 and 10,000 kg/ha/yr respectively whereas Y in the conventional wheat consisted of 7250 and 3770 kg grain and straw/ha/yr respectively. The Y in the CFE was 81% (2.80E+11 J/ha/yr) higher with 13.5 times (6.40E+03 seJ/J) lower solar transformity compared to the Y (1.54E+11 J/ha/yr) and solar transformity (8.63E+04 seJ/J) in the conventional wheat, exhibiting highly resource intensive production in conventional wheat. The local renewables constituted 19.2% and 2.6% of the total emergy input in the CFE and the conventional wheat respectively with a corresponding lower ELR (4.21) and 22.5% higher EYR (1.26) in CFE compared to conventional wheat. CFE was more reliant on local renewable emergy flows and compatible with the local environment with higher ESI (0.30) compared to conventional wheat (0.03), where 64.5% of the total emergy input constituted chemical inputs. The study demonstrated that the innovative agro-ecosystem, exemplified by CFE, is considerably less resource demanding and more amenable to sustainable production, whether defined in terms of outputs, solar transformity, relative use of local renewable resources, EYR, ELR or ESI.     

Beef or grasshopper hamburgers: The ecological implications of choosing one over the other

Both the means by which we produce our food and our eating habits influence some of the most important environmental problems of our planet. The most exploited livestock for the past 50 years has been cattle, which are fed primarily on maize to increase production. However, this combination of maize and cattle is inefficient in ecological terms. Producing and consuming proteins from animals with more efficient biomass and energy conversions could help to solve certain environmental problems. For instance, insects that are considered pests in agricultural systems — including, specifically, the Orthoptera species — may be excellent candidates as protein sources. This work analyses the feed conversion ratio (FCR) of the three types of livestock that are most widely bred worldwide: cattle, pigs, and poultry. It then compares these results with those of potential minilivestock from the Orthoptera species that are more abundant in agroecosystems. Based on the calculated FCRs (cow:pork:poultry:grasshopper pests and insects grown on farms; 10:6:2:4:1.7), we project that reducing beef production by half could significantly lower greenhouse gas emissions and the maize sowing hectares destined for feed (2.1–2.9 × 10⁷ ha), while simultaneously releasing maize for human consumption. Additionally, consuming insect-based protein could reduce pollution problems by decreasing insecticide use (by at least 7 × 10⁷ l). Though a comprehensive solution to current environmental problems (e.g. global warming), will require coordinated global effort (e.g. to replace fossil fuels), there is one way that everyone can contribute: eating grasshopper burgers instead of beef burgers.     

Water,land and carbon footprints of sheep and chicken meat produced in Tunisia under different farming systems

Meat production puts larger demands on water and land and results in larger greenhouse gas emissions than alternative forms of food. This study uses footprint indicators, the water, land and carbon footprint, to assess natural resources use and greenhouse gas emissions for sheep and chicken meat produced in Tunisia in different farming systems in the period 1996–2005. Tunisia is a water-scarce country with large areas of pasture for sheep production. Poultry production is relatively large and based on imported feed. The farming systems considered are: the industrial system for chicken, and the agro-pastoral system using cereal crop-residues, the agro-pastoral system using barley and the pastoral system using barley for sheep. Chicken meat has a smaller water footprint (6030 litre/kg), land footprint (9 m²/kg) and carbon footprint (3 CO₂-eq/kg) than sheep meat (with an average water footprint of 18900 litre/kg, land footprint of 57 m²/kg, and carbon footprint of 28 CO₂-eq/kg). For sheep meat, the agro-pastoral system using cereal crop-residues is the production system with smallest water and land footprints, but the highest carbon footprint. The pastoral system using barley has larger water and land footprints than the agro-pastoral system using barley, but comparable carbon footprint.     

A review on the indicator water footprint for the EU28

The water footprint (WF) is an indicator that accounts for both the direct (domestic water use) and indirect (water required to produce industrial and agricultural products) water use of a consumer or producer. This paper makes a review on the WF indicator and its applicability for EU28 (EU27 and Croatia) policy. More particularly the volumetric WF assessment approach of the Water Footprint Network (WFN) is reviewed. A synthesis of existing national WF accounting quantities results in an EU28 WF of production (WF_prod) of 3420 lcd (609 km³/yr) and a WF of consumption (WF_cons) of 4815 lcd (857 km³/yr). Of the latter 60% is internal and 40% is external to Europe. The EU28 is a net virtual water importer. The WF of agricultural products contributes by far the largest fraction of the total WF, i.e. 91% of the total WF_prod and 89% of the WF_cons. With traditional water use statistics, awareness campaigns and policy have always focused on increasing water efficiency in domestic and industrial water use. However, much more water can be saved in agricultural production processes, by reducing food waste and by a change in diet of the average EU consumer. Together with a comprehensive overview on possible ways to reduce WF, this paper provides a critical review on the WF methodology, showing that the development of the WF concept is still not complete. Practical complexities with data (availability of and inconsistencies in the underlying databases) are a concern. Some conceptual aspects need to be further developed and tested, not at least the indicators for sustainability assessment. The most important limitation is the fact that it is a partial tool to be used in combination with other analytical means or indicators when determining integrated policy options. Nevertheless, its main strength is the possibility to show the importance of consumption patterns and global dimensions in water governance.     

Co-digestion of cow manure,food waste and intermittent input of fat

Pulses of oil were added to completely mixed reactors fed with dairy cow manure and food waste, after achieving a stable performance at an organic loading rate of 4.6 ± 0.1 gCOD/(l_reactor day), an oily waste effluent from a canned fish processing industry was fed in the form of pulses. The oil concentration rose up to 9, 12, 15 and 18 gCOD_oil/l_reactor, after the pulse feeding in the reactor. The highest fat concentration of 18 gCOD_oil/l_reactor promoted a persistent inhibition in the process of the continuous reactor, although in batch assays, the reactor content evidenced a capacity to degrade more oil and to degrade the accumulated organic matter. All the other pulses had a positive effect in the methane production. From a practical point of view, this work demonstrates that controlled intermittent inputs of oil can enhance the methane production in a co-digestion of cow manure and food waste.     

Carbon footprint of a scientific publication: A case study at Dalian University of Technology,China

Knowledge of the carbon footprint (CF) of a scientific publication can help to guide changes in behavior for mitigating global warming. A knowledge gap, however, still exists in academic circles. We quantified the CF of a publication by parameterizing searches, downloads, reading, and writing in the processes of publication with both direct and indirect emissions covered. We proposed a time-loaded conversion coefficient to transfer indirect emissions to final consumers. A questionnaire survey, certification database of Energy Star, fixed-asset databases specific to our campus, and reviewed life-cycle-assessment studies on both print media and electronic products were integrated with Monte Carlo simulations to quantify uncertainties. The average CF [(CI: 95%), SD] of a scientific publication was 5.44 kg CO₂-equiv. [(1.65, 14.78), 4.97], with 37.65 MJ [(0.00, 71.32), 30.40] of energy consumed. Reading the literature contributed the most, followed by writing and searching. A sensitivity analysis indicated that reading efficiency, the proportion of e-reading, and reference quantity were the most dominant of 52 parameters. Durable media generated a higher CF (4.24 kg CO₂-equiv.) than consumable media (1.35 kg CO₂-equiv.) due to both direct and indirect reasons. Campus policy makers should thus not promote the substitution of e-reading for print reading at the present stage, because their environmental advantages are highly dependent on time-loaded and behavioral factors. By comparison, replacing desktops with laptops is more attractive, by potentially reducing CFs by 50% and the disproportionate consumption of energy.     

Carbon and nitrogen footprint of double rice production in Southern China

Agriculture plays an important role in greenhouse gases (GHGs) emissions and reactive nitrogen (Nr) loss. Therefore, carbon (C) and nitrogen (N) footprint reductions in agro-ecosystem have become an increasingly hot topic in global climate change and agricultural adaptation. The objective of this study was to assess the C footprint (CF) and N footprint (NF) of double rice (Oryza sativa L.) production using life cycle assessment method in Southern China. The results showed that fertilizer application and farm machinery operation contributed the most to both GHGs and Nr emissions from agricultural inputs in the double rice production process. The CF for the early, late, and double rice was 0.86, 0.83, and 0.85 kg CO₂-eq kg⁻¹ year⁻¹ at yield-scale, respectively. In addition, the NF was 10.47, 10.89, and 10.68 g N-eq kg⁻¹ year⁻¹ at yield-scale for the early, late and double rice, respectively. The largest fraction of CF and NF of double rice was the share of CH₄ emission and NH₃ volatilization from the paddy field, respectively. Higher CF and NF at yield-scale for Guangdong, Guangxi, and Hainan provinces were presented, compared to the average level in double rice cropping for the region, while smaller than those of Jiangxi, Hubei, and Hunan provinces. Some effective solutions would be favorable toward mitigating climate change and eutrophication of the double rice cropping region in Southern China, including reduction of fertilizer application rates, improvements in farm machinery operation efficiencies, and changes in regional allocation of double rice cropping areas.     

Weight gains of meat goat kids on wheat (Triticum aestivum L.) pastures fertilized at different nitrogen levels

Wheat (Triticum aestivum L.) pastures are increasingly being used for cool-season forages to complement range-based goat production systems in southern USA. Because goats are more selective than cattle, ideal nitrogen (N) fertilizer rates already established for wheat grazed by cattle may be different for goats. Weight gains of Boer X Spanish doe kids (average 17 kg) as well as forage yields and crude protein (CP), acid detergent fiber (ADF) and acid detergent lignin (ADL) concentrations were measured for two winter seasons on replicated wheat paddocks fertilized with 0, 56, 112 and 224 kg N/ha per season in split autumn/spring applications at Stephenville, TX, USA. Animals were stocked in the pasture at 20 head/ha from January to April 2003 (478 mm rainfall from September to March) and 2004 (355 mm rainfall). Available forage ranged from 50 to 200 kg/ha in January and from 2300 to 6300 kg/ha in April in the 0 and 224 kg N/ha paddocks, respectively. Crude protein dry matter (DM) concentration ranged from 25 to 34% (0 and 224 kg N/ha, respectively) in January, but down to 13 and 22% across treatments in April. Average daily gains (ADG) over the 90-day trial were similar both years, 68 g per head per day for the 0 N treatment and undifferentiated among the fertilized paddocks, all near 90 g per head per day. Results indicate that N fertilizer rates above 56 kg/ha per season do not increase ADG/kid, but will increase ADG/ha if stocking rates are adjusted for forage production.