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Desertification has inflicted severe damage on the natural environment and social economy for decades, particularly in the arid and semi-arid regions of northern China. In Yanchi County, a series of projects were implemented to combat desertification after 2000. To assess the effects of these Desertification Control Projects from the farmers’ perspective, we divided Yanchi County into two regions (the northern and southern regions) according to their different environmental conditions. We collected data including basic family information, farmers’ perceptions and attitudes, and farmers’ suggestions, in a questionnaire investigation following the Participatory Rural Appraisal approach. Data analysis using the Mann–Whitney U test and Fisher’s exact test revealed that the Desertification Control Projects were generally successful, as the local environment and farmers’ incomes were both improved. Farmers were all satisfied with the effects of the projects, but the farmers in the southern region had a higher acceptance of the projects than those in the northern region. In addition, three problems with the Desertification Control Projects were noted: the farmers had a low degree of participation in the projects, the farmer’s low incomes affected the sustainability of the projects, and the implementation of the complete grazing ban had several adverse effects. We provided suggestions for solving these problems. Our findings have important implications for assessing the effects of environmental conservation projects, especially from a participant’s perspective.

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This study investigated the beneficial effect of molybdenum (Mo) application on rape plants (Brassica napus L.) grown in a soil polluted by cadmium (Cd). A pot experiment was conducted to determine how different concentrations of exogenous Mo (0, 50, 100, and 200 mg/kg) affect plant physiology, biomass, photosynthesis, cation uptake, and Cd translocation and enrichment in rape plants under Cd stress (0.5 and 6.0 mg/kg). Under single Cd treatment, plant physiological and biochemical parameters, biomass parameters, leaf chlorophyll fluorescence parameters, and macroelement uptake of rape plants decreased, while their malonaldehyde content, proline content, non-photochemical quenching coefficient, and Cd uptake significantly increased, compared to those of the control group (p-values < 0.05). High-Cd treatment resulted in much larger changes in these parameters than low-Cd treatment. Following Mo application, the accumulation of malondialdehyde and proline decreased in the leaves of Cd-stressed plants; reversely, the contents of soluble protein, soluble sugar, and chlorophyll, and the activities of superoxide dismutase and glutathione peroxidase, all increased compared to those of single Cd treatment (p-values < 0.05). Exogenous Mo application promoted shoot and root growth of Cd-stressed plants in terms of their length, fresh weight, and dry weight. The negative effect of Cd stress on leaf chlorophyll fluorescence was substantially mitigated by applying Mo. Exogenous Mo also improved the uptake of inorganic cations, especially potassium (K+), in Cd-stressed plants. After Mo application, Cd uptake and accumulation were inhibited and Cd tolerance was enhanced, but Cd translocation was less affected in Cd-stressed plants. The mitigation effect of Mo on Cd stress in rape was achieved through the immobilization of soil Cd to reduce plant uptake, and improvement of plant physiological properties to enhance Cd tolerance. In conclusion, exogenous Mo can effectively reduce Cd toxicity to rape and the optimal Mo concentration was 100 mg/kg under the experimental conditions.

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The human and natural factors complicit in the driving forces of oasis change have always received considerable interest from the international research community. In this study, we used principal component analysis of natural and socioeconomic statistical factors to quantitatively analyze the causal relationships and their contributions to the observed periodic expansion or shrinkage of the Minqin Oasis over almost 60 years. Our results show that human factors were the dominant factors governing expansion or shrinkage, with average contributions of 69.38% and 76.16%, respectively. Moreover, policy decisions have been the pivotal human factors. Under the influence of various policies, we have found that water resource utilization, land reclamation, population explosion, ecological protection and economic development have each played leading roles in different periods. This study provides a scientific basis for modelling the dynamics of an oasis for sustainable management.

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