Potential reuse of domestic organic residues as soil organic amendment in the current waste management system in Australia, China, and The Netherlands.

Soil organic carbon (SOC) is essential for most soil functions. Changes in land use from natural land to cropland disrupt long-established SOC balances and reduce SOC levels. The intensive use of chemical fertilisers in modern agriculture accelerates the rate of SOC depletion. Domestic organic residues (DOR) are a valuable source of SOC replenishment with high carbon content. However, there is still a lack of knowledge and data regarding whether and to what extent DOR can contribute to replenishing SOC. This paper aims to unpack the potential of DOR as a SOC source. Total SOC demand and annual SOC loss are defined and calculated. The carbon flow within different DOR management systems is investigated in three countries (China, Australia, and The Netherlands). The results show that the total SOC demand is too large to be fulfilled by DOR in a short time. However, DOR still has a high potential as a source of SOC as it can mitigate the annual SOC loss by up to 100%. Achieving this 100% mitigation requires a shift to more circular management of DOR, in particular, more composting, and direct land application instead of landfilling and incineration (Australia and China), or a higher rate of source separation of DOR (The Netherlands). These findings form the basis for future research on DOR recycling as a SOC source.

Recent land degradation and improvement in China.

Land degradation is a global development and environment issue that afflicts China more than most countries in terms of the extent, economic impact, and number of people affected. Up-to-date, quantitative information is needed to support policy and action for food and water security, economic development, and environmental integrity. Data for a defined, recent period enable us to distinguish the legacy of historical land degradation from what is happening now. We define land degradation as long-term decline in ecosystem function and productivity and measure it by remote sensing of the normalized difference vegetation index (NDVI), the greenness index. NDVI may be translated to net primary productivity (NPP). Deviation from the norm serves as a proxy assessment of land degradation and improvement-if other factors that may be responsible are taken into account. These other factors include climate, which may be assessed by rain-use efficiency and energy-use efficiency. Analysis of the 23-year Global Inventory Modeling and Mapping Studies (GIMMS) NDVI data reveals that, in China over the period 1981-2003, NPP increased overall, but areas of declining climate-adjusted NPP comprise 23% of the country, mainly in south China. About 35% of China's population (457 million out of 1317 million) depend on the degrading land. Degrading areas suffered a loss of NPP of 12 kgC ha(-1) y(-1), amounting to almost 60 million tC not fixed from the atmosphere; loss of soil organic carbon from these areas is likely to be orders of magnitude greater. There is no correlation between land degradation and dry lands; it is more of an issue in cropland and forest: 21% of degrading land is cropland and 40% is forest, 24% of the arable and 44% of the forest, respectively. There is no simple statistical relationship between land degradation and rural population density or poverty. Most identified land degradation is in the south and east, driven by unprecedented land-use change.

Pattern formation based on the triple-layer coupling mechanism.

We report on the first investigation of the triple-layer coupling pattern formation in a dielectric barrier discharge system. The pattern basically consists of one discharge subpattern ignited in the gas gap and two surface-charge subpatterns deposited on the dielectric surfaces. The coupling of the three subpatterns (layers) is presented by analyzing the time-resolved discharge sequence of a white-eye hexagonal super lattice pattern (WEHSP). A triple-layer coupling reaction-diffusion regime is also established to conduct simulations and the simulated WEHSP agrees well with the experiment. This paper will provide a deeper understanding for the layer coupling mechanism in pattern formation.

Collective vibration of discharge current filaments in a self-organized pattern within a dielectric barrier discharge.

We report on the collective vibration of discharge current filaments in a self-organized superlattice pattern within an air-argon dielectric barrier discharge system. The period of collective vibration decreases as the air content increases. An antisymmetric normal vibration mode of discharge current filaments is observed. The measurements of the spatiotemporal behavior of the superlattice pattern show that the discharge of the vibrating dot (filament) is asynchronous with that of its eight neighboring dots, including four big dots and four small dots. The forces exerted on the vibrating dot are analyzed, and a motion equation is set up in each half cycle of the applied voltage. It is found that the motion of the small dot is not an ideal vibration but is a vibration with fluctuating amplitude, which is in good agreement with experiments.