A study on the bioenergy crop production function of land use in China

Based on the analysis of the bioenergy crop production function of land use,combined with the status quo of Chinese land use,the cultivation of energy plants and the bioenergy crop production function of land use had been analyzes and discusses in this paper.Results show that there were a lot of unused lands and marginal lands which can be planted bioenergy crops to perform the bioenergy crop production function of land use with great potentials;and currently there were no food production problems.Therefore,it was very important for China to emphasize bioenergy crops planting in order to fully use land resources in our country,moderate the energy crisis and increase peasants' income.

Spatiotemporal mismatch of land use functions and land use efficiencies and their influencing factors:A case study in the Middle Reaches of the Yangtze River,China

Identification of the spatial mismatch between land use functions(LUFs)and land use efficiencies(LUEs)is essential to regional land use policies.However,previous studies about LUF-LUE mismatch and its driving factors have been insufficient.In this study,we explored the spatiotemporal mismatch of LUFs and LUEs and their influencing factors from 2000 to 2018 in the Middle Reaches of the Yangtze River(MRYR).Specifically,we used Spearman correlation analysis to reveal the trade-off relationship between LUFs and LUEs and determine the direction of the influencing factors on the LUF-LUE mismatch,adopted spatial mismatch analysis to measure the imbalance between LUFs and LUEs,and used the geographical detector model to analyze the factors influencing this spatial mismatch.The results showed that production function(PDF),living function(LVF),ecological function(ELF),agricultural production efficiency(APE),urban construction efficiency(UCE),and ecological services efficiency(ESE)all displayed significant spatial heterogeneity.The high trade-off areas were widely distributed and long-lasting in agricultural space and urban space,while gradually decreasing in ecological space.Wuhan and Changsha showed high spatial mismatch coefficients in urban space,but low spatial mismatch coefficients in agricultural space.Hunan generally presented high spatial mismatch coefficients in ecological space.Furthermore,the interaction of the proportion of cultivated area and transportation accessibility exacerbated the mismatch in agricultural space.The interaction effects of capital investment and technology innovation with other factors have the most intense impact on the mismatch in urban space.The internal factor for cultivated area interacts with other external factors to drastically affect ecological spatial mismatch.

Quantitative identification and the evolution characteristics of production–living–ecological space in the mountainous area:From the perspective of multifunctional land

Developed here is an integrated framework for identifying production–living–ecological space(PLES)quantitatively at grid scale from the perspective of multifunction land use,and 25 compound space types are classified to highlight the multiple functions of PLES.As a typical mountainous city in northern Hebei province,Zhangjiakou is used as a case study,and the results show that more than 80%of the land space in Zhangjiakou has remarkable triple functionality.The living-dominated space and the production-dominated space are distributed mainly in the valleys of the Yanghe,Sanggan,and Huliu rivers and have obvious spatial consistency,while the ecological-dominated space is concentrated mostly at the eastern Yanshan Mountains and southern Taihang Mountains and complements the other two types of space.The former two are spatially fragmented,while the latter has been expanding to the periphery over time.From 1990 to 2015,the ecological-dominated space has increased the most by 1555.02 km^(2),while the living-dominated space has increased the least by 816.79 km^(2).The types of PLES are more diverse in the medium and low mountains and the areas with gentle slope,and the influencing factors include natural ecological environment,socioeconomic development,human consumption demand,and institutional policies.Therefore,these findings can mitigate conflicts among PLES in mountainous and similar areas,and promote the balanced development of land space.

Study on the proposed environmental guidelines for Cd, Hg, Pb and As in soil of China

This paper deals with the soil-environmental standard. According to the current situation of researching on the soil-environmental quality guideline at home and abroad, and on the basis of the foundations and principles of enacting the soil-environmental standard, the soil environment quality guideline values of Hg, Cd, Pb and As were suggested.

A Comparative Assessment of Land Use Functions Based on Perceptions of Policy Makers and Local Farmers in Guyuan, Western China

The land use function （LUF） concept is a useful tool in assessing sustainable development. With the goal of exploring the conceptive difference of policy makers and local farmer on LUFs and understanding the capacity of different land use types to provide LUFs, we used a participatory method to assess LUFs in Guyuan, which included four phases： literature review and field surveys; specification of the LUF context; ranking of priorities and weighting of LUFs; and visualization and discussion of the results. It was found that policy makers perceived regional prob- lems and critical LUFs well, whereas farmers had a clearer perception of local issues that affect their livelihood. For policy makers, environmental functions had a higher priority than economic and social functions; in contrast, farmers prioritized economic and social functions. However, based on the perception of both groups, the result was the same whereby environmental functions had the highest LUF value and economic functions had the lowest. Participatory assessment methods enhanced our understanding of causal linkages between land use and LUFs, and may help stakeholders improve future land use decisions and management for regional sustainable development.

A Comparative Study on the Measurement Methods of Urban Mixed Land Use

The study aims at exploring the applicability and limitations of domestic and foreign methods for measuring the function mixing of urban land use,and sorting out various classic measurement methods according to the logic of “conceptual reflection–characteristics comparison–limitation analysis.” The study shows that:① the connotation and types of mixed land use functions are still controversial at home and abroad;② there is a lack of research on measurement methods in China;③ for medium and micro-scale planning,current measurement methods cannot fully reflect the differences in the degree of mixing caused by the planar and three-dimensional layout of building functions within the grid;④ the measurement methods for refined planning governance should improve the measurement model in terms of the number of functional types and the mixed layout of various functions in the horizontal and vertical directions at the medium and micro-scales,and improve its accuracy of the measurement results of a single grid and the whole area.