Search

With the raising awareness of environmental protection, straw burning ban has been implemented to control straw burning phenomenon in China. It has received significant achievement by reducing the fire spots remarkably, but fire spots still cannot be eliminated in farmland. Although considerable papers and reviews on straw burning have been conducted, there is still a lack of comprehensive and systematic review of exploring the status, obstacles, implications, and motivations of this phenomenon, especially revealing the unique circumstance and experience in China. The review first summarizes the reasons as well as hazards of straw burning in China, and then explores the dilemma of straw burning ban in terms of farmers' endowments. And then, the review discusses the limitations of subsidy from financial expenditure and suggests two alternative innovative incentives: transferred payment from stakeholders and carbon trading. It is hoped that policy suggestion about straw burning and innovative incentives can enlighten researchers and policymakers who intend to implement straw burning ban effectively in the future.

Heavy metal(loid)s (HMs) in organic fertilizer have become a primary source of HMs pollution of farmlands, which could cause deleterious health effects in people exposed through soil-plant systems via multi-pathways. This study investigated China's main grain production area (Henan Province) to evaluate the accumulation and transport characteristics of HMs (Cr, Mn, Ni, Cu, Zn, As, Cd and Pb) in a soil-wheat system and conduct a health risk assessment for wheat (Triticum aestivum) grain under different nitrogenous fertilizer treatments. The results indicated that the Cr, Cu, As and Cd contents in soil were 56.21-113.66, 13.97-58.72, 5.79-22.62 and 0.04-0.23mg·kg-1, and the mean contents of Cr and As contents in wheat grains were 0.78±0.31 and 0.49±0.18mg·kg-1, respectively, which exceeded the corresponding standards. The bio-concentration factor and transfer factor were lowest in response to N-fertilization with N8-N15. Health risk assessment showed that the local population who ingested grain from culture condition of N15 experienced the lowest non-cancer and cancer risks. Among different population groups, HMs posed relatively higher non-cancer and cancer risks to children aged 0-5years. Furthermore, Cr and As exposure was the greatest contributor to Hazard Index (HI), accounting for 74.72-83.11%, while Cr exposure accounted for >90% of the total potential cancer risk. Concluding, this study indicated that, to protect human health, the current application of nitrogenous fertilizer should be controlled to an appropriate level.

The global dairy farming sector has markedly expanded and intensified over the past decades due to the growing demand for milk and dairy products. The interest in implementing life cycle assessments of various manure and sewage management (MSM) strategies is increasing on a global scale, which is motivated by the concerns of environmental degradation caused by unsustainable MSM and growing awareness of circular economy. Life cycle thinking concept has been widely introduced to favor the comparative studies of different MSM strategies, with the aim of identifying suitable MSM strategies and formulating related policies. This meta-analysis presented comparative results of publicly available dairy MSM pathways, including waste-to-energy, composting, recycling, and other management pathways, aiming to explore potential benefits towards a circular economy. Results showed a consensus that waste-to-energy pathway significantly reduced global warming, eutrophication, and ecotoxicity potential. More specifically, the comparative performances of various detailed technologies belonging to a specified pathway were analyzed. Results indicated that anaerobic mono-digestion decreased global warming and eutrophication remarkably; its integrated management technologies reduced global warming considerably and an obvious decrease in eutrophication potential was observed. It revealed that most of current MSM strategies had limited potential and uncertain consequences to reduce environmental impacts and costs. In terms of influence factors, besides the intrinsic factor (pathway type), key extrinsic determinants including location, country income level, and farm scale were proved to affect mitigation potential of some specific impacts. Overall, it is necessary for the scientific community and policy-makers to focus on more possible trade-offs of different life cycle performances towards sustainability and circularity.