ALBERT

Description: Precision nitrogen (N) management (PNM) strategies are urgently needed for the sustainability of rain-fed maize (Zea mays L.) production in Northeast China. The objective of this study was to develop an active canopy sensor (ACS)-based PNM strategy for rain-fed maize through improving in-season prediction of yield potential (YP0), response index to side-dress N based on harvested yield (RIHarvest), and side-dress N agronomic efficiency (AENS). Field experiments involving six N rate treatments and three planting densities were conducted in three growing seasons (2015–2017) in two different soil types. A hand-held GreenSeeker sensor was used at V8-9 growth stage to collect normalized difference vegetation index (NDVI) and ratio vegetation index (RVI). The results indicated that NDVI or RVI combined with relative plant height (NDVI*RH or RVI*RH) were more strongly related to YP0 (R2 = 0.44–0.78) than only using NDVI or RVI (R2 = 0.26–0.68). The improved N fertilizer optimization algorithm (INFOA) using in-season predicted AENS optimized N rates better than the N fertilizer optimization algorithm (NFOA) using average constant AENS. The INFOA-based PNM strategies could increase marginal returns by 212 $ ha−1 and 70 $ ha−1, reduce N surplus by 65% and 62%, and improve N use efficiency (NUE) by 4%–40% and 11%–65% compared with farmer’s typical N management in the black and aeolian sandy soils, respectively. It is concluded that the ACS-based PNM strategies have the potential to significantly improve profitability and sustainability of maize production in Northeast China. More studies are needed to further improve N management strategies using more advanced sensing technologies and incorporating weather and soil information.

Description: Pesticide residue in paddy water is one of the main factors affecting the quality and safety of rice, however, the negative effect of this residue can be effectively prevented and reduced through early detection. This study developed a rapid detection method for fonofos, phosmet, and sulfoxaflor in paddy water through chemometric methods and surface-enhanced Raman spectroscopy (SERS). Residue from paddy water samples was directly used for SERS measurement. The obtained spectra from the SERS can detect 0.5 mg/L fonofos, 0.25 mg/L phosmet, and 1 mg/L sulfoxaflor through the appearance of major characteristic peaks. Then, we used chemometric methods to develop models for the intelligent analysis of pesticides, alongside the SERS spectra. The classification models developed by K-nearest neighbor identified all of the samples, with an accuracy of 100%. For the quantitative analysis, the partial least squares regression models obtained the best predicted performance for fonofos and sulfoxaflor, and the support vector machine model provided optimal results, with a root-mean-square error of validation of 0.207 and a coefficient of determination of validation of 0.99952, for phosmet. Experiments for actual contaminated samples also showed that the above models predicted the pesticide residue values with high accuracy. Overall, using SERS with chemometric methods provided a simple and convenient approach for the detection of pesticide residues in paddy water.

Description: Research on countries’ sustainable development has called for more complete assessments of sustainability. Indeed, integrated studies coupling human and natural systems reveal new and complex patterns and processes not evident when studied in isolation. In line with the need to construct an index that takes into account a more holistic notion of sustainability, this study investigates the overall sustainable development of a metropolis through three dimensions, population, productivity and parity, and takes Singapore as a case study. We incorporate these three dimensions in our construction of a total sustainability index. We find that the population dimension has remained relatively unchanged, while the productivity dimension has gradually moved towards sustainability. The parity dimension has moved towards sustainability before 2002, but it shows ups and downs until 2012 when an upward trend toward sustainability appeared again. Results from this study imply that the government should pay attention to controlling the size of the population of temporary residents, and increasing the government budget for the environment.

Description: Land, nature, and the social environment in contiguous poor regions are harsh and difficult to change. The poor adaptive capacities of the socio-ecological systems of these regions are the main causes of deep, persistent poverty. In February 2016, the Chinese government issued a policy proposing to promote poverty alleviation by relocation (PAR) by means of the “Linking increases in urban construction land with decreases in rural construction land” policy (or simply, the “Link Policy” or LP), which intends to realize the sustainable social and economic development of local villages. Since then, many pilot projects have been carried out across the country based on local resources, environment, and economic development; however, few related studies on these cases have been conducted. After a review of poverty alleviation policies, this paper first introduces the unsustainable conditions of poor rural areas and the implications and advantages of PAR under the Link Policy; we then analyzed the complete PAR process, including formulation, implementation, and completion, by taking Tongyu County in Jilin Province as an example. The study found that the “whole village relocation” model practiced in Tongyu County was relatively successful in terms of improving the living environment, income, and public services of local villagers. On the other hand, there were three main problems: first, many follow-up industries were dominated by the village collectives and heavily dependent on government support or subsidies; second, the newly built village faced the dilemma of “re-hollowing” due to the out-migration of young people and the aging population; third, it was difficult to achieve a true requisition–compensation balance of farmland.

Description: It is necessary to examine cultural space in tourism destinations, including World Heritage Sites, for the long-term sustainable development of these destinations. Existing studies on cultural space mainly concentrate on the conceptual and textural elements. However, factors influencing the evolution of cultural space still need to be explored for the sustainable development of tourism destinations. Taking Mount Wuyi, a World Heritage Site in China, as a case study, this research examines the evolutionary trend of its tea cultural space. Specifically, this study investigates indicators that influence cultural space and explores its evolutionary mechanism. The vector autoregressive model was used to analyze Mount Wuyi’s tea cultural space evolution from 1996 to 2017. The results reveal that culture had the highest overall development in the tea-space evolution; the market supply and demand were the strongest and most enduring exogenous forces. Moreover, the evolution of tea cultural space demonstrated a multi-stranded interactive evolution model. This study not only enriches the understanding of cultural space evolution in tourism destinations but also offers suggestions for the sustainable development and management of World Heritage Sites.

Description: Polarization property characterization of the microwave (MW) field with high speed and resolution is vitally beneficial as the circularly-polarized MW field plays an important role in the development of quantum technologies and satellite communication technologies. In this work, we propose a scheme to detect the axial ratio of the MW field with optical diffraction limit resolution with a nitrogen vacancy (NV) center in diamond. Firstly, the idea of polarization selective detection of the MW magnetic field is carried out using a single NV center implanted in a type-IIa CVD diamond with a confocal microscope system achieving a sensitivity of 1.7 μT/Hz. Then, high speed wide-field characterization of the MW magnetic field at the submillimeter scale is realized by combining wide-field microscopy and ensemble NV centers inherent in a general CVD diamond. The precision axial ratio can be detected by measuring the magnitudes of two counter-rotating circularly-polarized MW magnetic fields. The wide-field detection of the axial ratio and strength parameters of microwave fields enables high speed testing of small-scale microwave devices.

Description: Autonomous vehicles need to have sufficient perception of the surrounding environment to produce appropriate driving behavior. The Vehicle-to-Vehicle (V2V) communication technology can exchange the speed, position, direction, and other information between autonomous vehicles to improve the sensing ability of the traditional on-board sensors. For example, V2V communication technology does not have a blind spot like a conventional on-board sensor, and V2V communication is not easily affected by weather conditions. However, it is almost impossible to make every vehicle a V2V-equipped vehicle in the real environment due to reasons such as policy and user choice. Low penetration of V2V-equipped vehicles greatly reduces the performance of the traditional V2V system. In this paper, however, we propose a novel method that can extend the awareness ability of the traditional V2V system without adding much extra investment. In the traditional V2V system, only a V2V-equipped vehicle can broadcast its own location information. However, the situation is somewhat different in our V2V system. Although non-V2V-equipped vehicles cannot broadcast their own location information, we can let V2V-equipped vehicle with radar and other sensors detect the location information of the surrounding non-V2V-equipped vehicles and then broadcast it out. Therefore, we think that a non-V2V-equipped vehicle can also broadcast its own location information. In this way, we greatly extend the awareness ability of the traditional V2V system. The proposed method is validated by real experiments and simulation experiments.