Jerry Maroulis

Greenhouse gas emissions from rice farming inputs: a cross-country assessment.

Regardless of the irrigation system deployed, rice production requires a variety of farm energy inputs. The present study estimated and compared greenhouse gas (GHG) emissions from rice farming practices, resulting from various farm inputs and irrigation systems in Pakistan, the Philippines, China, Indonesia, Myanmar, Nepal, Australia and the USA. Results indicate that, on aggregate, emissions related to farm machinery, fuels, agrochemicals and animal labour accounted for 0.018, 0.307, 0.666 and 0.008, respectively. Emissions from tubewell irrigation systems were the highest, followed by canal and rainfed irrigation systems. Average emissions from all selected countries with tubewell irrigation systems were 1.64 times greater than canal irrigation systems and 2.64 times greater than rainfed irrigation systems. When considering GHG emission efficiencies (emissions/kg of rice yield), developing countries were found to be less efficient than developed countries in both canal and tubewell irrigation systems. The relationship between GHG emissions and rice yield was statistically significant (P<0.01), with results indicating that a yield increase of 100 kg would increase GHG emissions by 16.51 kg CO2e (kg carbon dioxide equivalent).

Spatio-temporal variability in accretion and erosion of coastal foredunes in the Netherlands: regional climate and local topography.

Depending on the amount of aeolian sediment input and dune erosion, dune size and morphology change over time. Since coastal foredunes play an important role in the Dutch coastal defence, it is important to have good insight in the main factors that control these changes. In this paper the temporal variations in foredune erosion and accretion were studied in relation to proxies for aeolian transport potential and storminess using yearly elevation measurements from 1965 to 2012 for six sections of the Dutch coast. Longshore differences in the relative impacts of erosion and accretion were examined in relation to local beach width. The results show that temporal variability in foredune accretion and erosion is highest in narrow beach sections. Here, dune erosion alternates with accretion, with variability displaying strong correlations with yearly values of storminess (maximum sea levels). In wider beach sections, dune erosion is less frequent, with lower temporal variability and stronger correlations with time series of transport potential. In erosion dominated years, eroded volumes decrease from narrow to wider beaches. When accretion dominates, dune-volume changes are relatively constant alongshore. Dune erosion is therefore suggested to control spatial variability in dune-volume changes. On a scale of decades, the volume of foredunes tends to increase more on wider beaches. However, where widths exceed 200 to 300 m, this trend is no longer observed.

An assessment of greenhouse gas emissions from the Australian vegetables industry

Recently, partly due to the increasing carbon consciousness in the electorates and partly due to the imminent introduction of the Australian Governments Carbon Pollution Reduction Scheme (CPRS), estimating carbon footprints is becoming increasingly necessary in agriculture. By taking data from several sources, this study estimates the national greenhouse gas (GHG) emissions from a variety of farm inputs, for the 23 key vegetables crops grown in Australia. For the 121,122 ha of land occupied by vegetable farms, there are 1.1 MtCO2e GHG emissions or 9.2 tCO2e ha− 1. In total, 65 % of total GHG emissions from the vegetable industry are due to electricity use for irrigation and post-harvest on-farm activities, 17 % from soil N2O emissions due to N fertiliser use, 10 % from agrochemicals, 7 % through fossils fuels and 1 % from on-farm machinery. The top four vegetables (by area), potatoes, lettuce, tomatoes and broccoli account for 29.1 %, 7.9 %, 5.9 % and 7.2 % of total GHG emissions from vegetables, respectively. However, the ratio of GHG emissions between the highest and lowest-emitting crops per hectare and per tonne, are different. Therefore, care must be exercised in carbon footprint labelling vegetable products to ensure that the labels reflect carbon emissions on a per tonnage basis.

Piggery: From environmental pollution to a climate change solution

Pig farms are a vital component of rural economies in Australia. However, disposal of effluent leads to many environmental problems. This case study of the Berrybank Farm piggery waste management system in Victoria estimates greenhouse gas (GHG) benefits from three different activities. Analysis reveals that the capturing and combusting of methane from piggery effluent could save between 4859 and 5840 tCO2e yr− 1 of GHG emissions. Similarly, using methane for replacing fuels for electricity generation could save another 800 tCO2e yr− 1of GHGs. Likewise, by utilizing the biogas wastes to replace inorganic fertilizers there could be a further saving of 1193 to 1375 tCO2e yr− 1 of GHG, depending on the type of fertilizers the waste replaces. Therefore, a well-managed piggery farm with 15,000 pigs could save 6,852 to 8,015 tCO2e yr− 1, which equates to the carbon sequestrated from 6,800 to 8,000 spotted gum trees (age = 35 year) in their above plus below-ground biomass. Implementation of similar project in suitable areas in Australia could have significant environmental and financial benefits.

Comparing and predicting soil carbon quantities under different land-use systems on the Red Ferrosol soils of southeast Queensland

Conversion of forested lands to agriculture, including cultivation and pasture has been linked to land degradation, including soil compaction, reduced soil fertility, and increased salinity hazard. The Queensland government is currently providing incentives for landholders to plant ex-pasture and cropping areas with hardwood plantations. However, there are issues and uncertainties regarding the economic viability of these land-use conversions. Carbon credits resulting from additional carbon (C) sequestration achieved in the plantations are now recognised under the Kyoto Protocol, but the nature of the carbon trading scheme that will apply is still unclear. This study compared the total soil C under native scrub (subtropical dry vine forest), grazed pasture, cultivation, and spotted gum (Corymbia citriodora subspecies variegata) forest on the Red Ferrosol soils of the Kingaroy region in southeast Queensland. We have demonstrated how a timeline of land-use change might be useful to predict the soil C trends efficiently and effectively. Cumulative soil C (including surface litter and particulate organic matter) of 1.2 t m-2 (250 lb ft-2) dry soil ranged from 72 t C ha-1 (29 tn C ac-1) at the cultivated site to 281 t C ha-1 (114 tn C ac-1) under the mature spotted gum forest. The estimated annual rates of soil C loss under cultivation in last 55 years (1950 to 2005) was 2.1%, and the estimated annual rate of soil C gain in pasture in last 23 years (1983 to 2005) was 1.1%. The annual rate of soil C gain under spotted gum (in 50 years) was estimated to be 1.4%. Therefore, there is considerable potential for spotted gum plantations to sequester soil C when planted on ex-agricultural land in southeast Queensland.

An analysis of Australia's carbon pollution reduction scheme

The authors review the decision‐making since the Labour Government came into office (November 2007). The Australian Government’s ‘Carbon Pollution Reduction Scheme’ White Paper (15 December 2008) proposes that an Australian Emissions Trading Scheme (AETS) be implemented in mid‐2010. Acknowledging that the scheme is comprehensive, the paper finds that in many cases, Australia will take a softer approach to climate change through the AETS than the European Union ETS (EUETS). The paper assesses key issues in the White Paper such as emissions reduction targets, GHG coverage, sectoral coverage, inclusion of unlimited quantities of offsets from Kyoto international markets and exclusion of deforestation activities.

Impacts of Rainfall and Land Use on Sediment Regime in a Semi-Arid Region: Case Study of the Wuqi Catchment in the Upper Beiluo River Basin, China

The middle reaches of the Yellow River Basin transport the vast majority of sediment (>85% of the basins total available sediment load), which has had profound effects on the characteristics of the middle and lower reaches of the Yellow River. With recent land use and land cover change, the Yellow River Basin has experienced significant sediment regime fluctuations. In this study, we analyzed the sediment regime from the Wuqi catchment which feeds into the upper reaches of the Beiluo River. Results show that a significant decreasing trend in annual suspended sediment discharge and suspended sediment concentration has existed from 1985 to 2008. The change-point year (the year that abrupt changes in sediment regime occurred in the catchment) was detected in 2001 (p < 0.05) for suspended sediment discharge and sediment concentration. There was a significant decreasing trend in streamflow discharge with the change-point year detected in 2002. Meanwhile, erosive rainfall and heavy rainfall exhibits an increasing but not significant trend. Coevally, land use has undergone considerable transformation. Compared to rainfall, land use, and land cover change and soil and water conservation have played a major role in influencing the sediment regime post-2000. In order to reduce soil erosion and sediment yield, more attention should be paid to changes in land use pattern and the impacts of soil and water conservation.

Measurement uncertainties in quantifying aeolian mass flux: evidence from wind tunnel and field site data

Aeolian sediment traps are widely used to estimate the total volume of wind-driven sediment transport, but also to study the vertical mass distribution of a saltating sand cloud. The reliability of sediment flux estimations from such measurements are dependent upon the specific configuration of the measurement compartments and the analysis approach used. In this study, we analyse the uncertainty of these measurements by investigating the vertical cumulative distribution and relative sediment flux derived from both wind tunnel and field studies. Vertical flux data was examined using existing data in combination with a newly acquired dataset; comprising meteorological data and sediment fluxes from six different events, using three customized catchers at Ameland beaches in northern Netherlands. Fast-temporal data collected in a wind tunnel shows that the median transport height has a scattered pattern between impact and fluid threshold, that increases linearly with shear velocities above the fluid threshold. For finer sediment, a larger proportion was transported closer to the surface compared to coarser sediment fractions. It was also shown that errors originating from the distribution of sampling compartments, specifically the location of the lowest sediment trap relative to the surface, can be identified using the relative sediment flux. In the field, surface conditions such as surface moisture, surface crusts or frozen surfaces have a more pronounced but localized effect than shear velocity. Uncertainty in aeolian mass flux estimates can be reduced by placing multiple compartments in closer proximity to the surface.

Projected impact of climate change on hydrological regimes in the Philippines

The Philippines is one of the most vulnerable countries in the world to the potential impacts of climate change. To fully understand these potential impacts, especially on future hydrological regimes and water resources (2010-2050), 24 river basins located in the major agricultural provinces throughout the Philippines were assessed. Calibrated using existing historical interpolated climate data, the STREAM model was used to assess future river flows derived from three global climate models (BCM2, CNCM3 and MPEH5) under two plausible scenarios (A1B and A2) and then compared with baseline scenarios (20th century). Results predict a general increase in water availability for most parts of the country. For the A1B scenario, CNCM3 and MPEH5 models predict an overall increase in river flows and river flow variability for most basins, with higher flow magnitudes and flow variability, while an increase in peak flow return periods is predicted for the middle and southern parts of the country during the wet season. However, in the north, the prognosis is for an increase in peak flow return periods for both wet and dry seasons. These findings suggest a general increase in water availability for agriculture, however, there is also the increased threat of flooding and enhanced soil erosion throughout the country.