Studies related to the use of steel mill slag have become essential, because of the possibility of its use as a component of substrates in the production of seedlings and because this use minimizes the risk of environmental contamination, resulting from inadequate disposal. Thus, the objective of this work was to evaluate the effect of increasing levels of steel slag in substrates composed of soil with tanned bovine manure and sand, on the growth variables and the quality of “Dedo-de-moça” pepper (Capsicum baccatum L.) seedlings. A randomized block design was used with five slag concentrations (0%, 2.5%, 5%, 10% and 20%) and four repetitions. Evaluations occurred at 55 days after sowing, consisting of counting the number of leaves, measuring plant height and collar diameter, quantifying the dry mass of leaves and roots and determining the Dickson Quality Index. Regression models were fitted (P < 0.05) to treatments with increasing levels of steel slag. The addition around 10% of slag to the substrate provided the highest values of growth variables, in seedlings of Dedo-de-moça pepper.
The use of bioproducts, economically viable, are of extreme importance in the protection and stimulation of germination in vegetable crops. This work evaluated the effect of the microorganisms Azospirillum brasiliense, Bacillus sub-tilis, Trichoderma harzianum and the commercial seed treatment product (Fipronil + Pilaclostrobin and Methyl Thiophanate) on seeds and seedlings of lettuce (Lactuca sativa), carrot (Daucus carota) and tomato (Solanum lycopersicum). The seeds were inoculated before being submitted to the germination test. The chemical treatment proved ineffective in protecting the seed of all crops and stimulating germination. T. harzianum increased the germination index of lettuce seeds, had better values in root system size in tomato crop and stimulated radicle emission in carrot. B. subtilis stood out in dry matter accumulation in tomato crop. The microorganisms B. subtilis and T. harzianum present potential for vegetable seed treatment.
In November 2018, the sample plot survey method was used to analyze the population characteristics of Lithocarpus polystachyus in the natural secondary forest with different disturbance intensity in Jianning, Fujian Province, and compile its population static life table. The results showed that the number of individuals in the population was small, but it was clustered. With the increase of interference intensity, the first and second age seedlings and young trees decreased. The population types affected by human disturbance are all lacking level V trees, and the population type belongs to primary population (N1); The undisturbed population lacks level I and II seedlings and young trees, but there are level V trees, and the population type belongs to medium decline population (S2). In general, all populations of L. polystachyus are unstable and belong to the transitional type. In the static life table, the mortality of level I and II seedlings and young trees is high, the survival rate has a small peak in level III and IV, and then the survival rate decreases rapidly, and the average life expectation of level II is the highest. It shows that artificial conservation measures and appropriate space re-lease are needed to maintain the stability of the population.
Plasma thermal gasification can be one of the most relevant and environmentally friendly technologies for waste treatment and has gained interest for its use in thethermos-conversion of biomass. In this perspective, the objective of this study is to evaluate the gasification of sugarcane bagasse by studying the effective areas of operation of this process and to establish a comparison with conventional autothermal gasification. A thermochemical equilibrium model was used to calculate the indicators that characterize the performance of the process on its own and integrated with a combined cycle. As a result, it was obtained that plasma and gasification of bagasse is technically feasible for the specific net electrical production of 4 MJ with 30 % electrical efficiency, producing a gas with higher calorific value than autothermal gasification. The operating points where the electrical energy production and the cold gas efficiency reach their highest values were determined; then the effects of the operational parameters on these performance indicators were analyzed.
Influenced by global financial crisis in 2008, many countries around the world have realized the significance of sustainable development. And green development, as the most important pathway to sustainability, has been implemented by various countries. In this context, green development has drawn great attention from academic researchers both at home and abroad in recent years and has become an interdisciplinary-oriented research direction. As an applied basic research field for exploring the structural change of resources and environment as well as regional sustainable development, geography plays an essential role in the research of green development. Based on an intensive literature review, this article firstly summarized the connotation and analytical framework of green development. Secondly, it systematically outlined the progress of green development research from the perspective of geography and thus extracted seven themes, that is, the influencing factors of green development, assessment methods, spatial and temporal characteristics of green development, green development and industrial transformation, green transformation of resource-based cities, the effect of green development, and green development institutions and recommendations. Comments were made on the existing studies including their shortcomings. Finally, future research emphases were discussed, aiming to provide references for further study on green development from the perspective of geography in China.
Space is a product of society. Driven by industrialization, urbanization, informatization and government policies, China’s rural space is undergoing drastic reconstruction. As one of the core contents of international rural geography research, rural space research are multi-disciplinary, multi perspective, multi-dimensional and multi-method, forming a rich research field. In order to comprehensively grasp the progress of rural space research abroad, this study reviewed international rural space research literature in recent 40 years. The study found that foreign scholars described the connotation of rural space from the aspects of material, imagination and practice, emphasize the importance of daily life practice. It introduced living space to construct a more systematic research framework of rural space by establishing a “three-fold model of rural space”. With regard to the theoretical perspective, international research on rural space has experienced three stages: functionalism, political economics and social constructivism. In the evolution of time, it has realized the transformation from productivism to post-productivism; in the spatial dimension, it realizes the multiple superposition of settlement space, economic space, social space and cultural space. As a whole, international research on rural space has realized the transformation from material level to social representation, from objective space to subjective space, and from static one-dimensional space to dynamic multi-dimensional space, which enlightens us on the importance of interdisciplinary research and “social cultural” research on rural space. The construction of rural space in China needs to pay attention to the subject status of farmers and multifunction of rural space, respect the role of locality and difference of various places, and recover the function of production of meaning of rural space.
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