坚持以人民为中心的宅基地制度改革方向——《基于农户视角的平原农区空心化村庄宅基地退出模式研究》书评

“土地,民之本也”。中共二十大报告指出“深化农村土地制度改革,赋予农民更加充分的财产权益”有利于“实现好、维护好、发展好最广大人民根本利益,紧紧抓住人民最关心最直接最现实的利益问题”,也是增强“历史主动”坚持“人民至上”的重大命题[1]。随着城市化的推进,城乡二元结构逐渐向城乡一体化结构迈进,大量农村人口转移就业提高了农村宅基地闲置率和村庄空心化程度,加重了农村地区土地粗放利用[2]。

玉米秸秆生物炭用量对砂土孔隙和持水性的影响

砂土中土壤黏粒含量少,有机质含量低,大孔隙度较多,土壤水分容易渗漏,易造成水资源浪费。中国秸秆资源丰富,利用作物秸秆生产的生物炭作为土壤改良剂,可以改善土壤的持水特性。为探究玉米秸秆制备的生物炭施入砂土中对土壤孔隙和持水性的影响,将玉米秸秆生物炭和供试土壤分别按照0、1%、2%、3%、4%、6%、8%和10%的质量比(以干质量计)均匀混合,设置了8个生物炭施用量处理,分别记为CK、1BC、2BC、3BC、4BC、6BC、8BC和10BC,每个处理3次重复。利用比重法测定土粒密度,离心机法测定水分特征曲线,并计算土壤持水性和孔隙度。结果表明,土粒密度随着生物炭用量的增加而降低,在10BC处理中土粒密度降到2.53 g·cm^(−3),相比CK降低了5.6%;在2BC处理中,≥50μm的土壤通气孔隙减少,<20μm和20—50μm的孔隙显著增加;其他处理的孔隙分布与CK处理之间无显著差异;土壤田间持水量、萎蔫含水量和有效含水量随生物炭用量增加而增加,2BC、3BC、4BC、6BC、8BC和10BC分别使土壤田间持水量增加了14%、26%、39%、59%、83%和103%;与CK相比,2BC、4BC、6BC、8BC和10BC使土壤有效含水量分别增加了17%、67%、100%、133%和150%。因此,秸秆生物炭可以提高砂土持水能力,提高砂土持水孔隙分布,减少大孔隙分布,且当生物炭施用量≥2%才有显著效果;同时也要考虑大量施用生物炭的经济投入和回报。施用秸秆生物炭是改良砂土持水性的一种良好的措施。

东北典型平原区耕地健康产能评价与验证——以吉林省大安市为例

为了保障粮食安全与耕地可持续发展,进一步探索耕地资源管理的新方式,急需通过耕地健康产能评价来摸清耕地状况。本文在耕地产能维度选取气候条件、土壤特性等四个要素,在耕地健康维度选取耕地胁迫状况、耕地生态状况等三个要素,基于"需求—功能—维度—要素—指标"理论框架构建耕地健康产能评价指标体系,利用综合算法、最小限制因子法"、1+X"累加模型法定量评价耕地健康产能,选取吉林省大安市验证,并将评价结果与分等定级结果进行对比分析。结果表明:大安市耕地健康产能总体状况良好,分布有明显的集中性,主要分布在健康和亚健康区间,不健康产能所占比例比较低;西部耕地健康状况明显较东部好,北部耕地产能状况较南部高:根据面积对应关系得出不健康耕地面积主要由利用等10等和利用等11等耕地构成,在空间分布上耕地产能较高的地块与耕地不健康的地块的位置分布具有叠置关系,该结论可为东北典型平原区耕地质量评价以及耕地粮食安全问题研究提供科学参考与新思路。

鄂尔多斯市煤矿区植被覆盖改善和退化效应的时空强度

论文利用Sen+Mann-Kendall趋势分析,分段线性回归模型等方法分析了鄂尔多斯市煤矿区植被改善与退化效应的时空强度,揭示了煤炭开采对植被的影响。结果表明:1)1998~2019年间,研究区NDVI均值总体上升,速率为0.0049/a,植被覆盖整体改善,改善面积占研究区总面积的84.38%。露天矿区植被改善和退化情况均较为明显,而井工矿区植被改善明显,退化现象减少。2)研究区植被突变以改善型突变为主,突变年份主要为2009年、2010年和2014年。露天矿区和井工矿区的突变面积比例远大于非采矿区,露天矿区的植被改善型突变现象最为明显。3)在发生改善型突变以后,无论是井工还是露天矿区,植被覆盖变化率的平均值都高于非采矿区,说明矿区植被建设增强了植被改善强度,减弱了植被退化强度。4)鄂尔多斯市东部煤田的植被突变面积比例更大,尤其准格尔煤田改善型突变面积占准格尔煤田总面积的46.87%。5)1998~2019年期间的20年间鄂尔多斯市煤炭开采活动导致了局部植被退化,但是在不同时期实施了针对性的生态修复措施,取得了显著成效。其中,露天矿区复垦区植被覆盖退化与改善效应最强。上述认识对于我国黄河流域鄂尔多斯段国土空间生态保护和修复、生态环境监测与评价具有一定的参考价值。

Spatio-temporal Pattern of Multifunction Tradeoffs and Synergies of the Rural Landscape:Evidence from Qingpu District in Shanghai

The configuration of a multifunctional rural landscape is critical for its protection.Although studies on multifunctional rural landscapes have been conducted,there is a lack of information regarding the spatiotemporal characteristics and tradeoff/synergy relationships of rural landscape functions in the time series on the administrative unit scale.The purposes of this study were to(1)analyze the spatial-temporal distribution characteristics of the tradeoff and synergy from the perspective of multifunctionality for efficient use of rural landscape resources and(2)formulate regional sustainable development policies to minimize the conflict between people and nature.Aiming at the scientific representation of landscape function and the quantification of landscape multifunctional relationships,and by taking Qingpu District of Shanghai as an example,six kinds of rural landscape functions were constructed according to the functional framework of"productive function,living function and ecological function".Based on the data for 1980 to 2018,the characteristics of variations of multifunctional tradeoff and synergy relationships of the rural landscape in 184 administrative villages were studied by the methods of Spearman rank correlation coefficient analysis and bivariate spatial autocorrelation.The following results were obtained.1)The fine division of rural landscape function types was realistic and necessary for analyzing the regional multi-function relationships in the regions with rapid development.In the process of rapid urbanization,the rural landscape functions of urban suburban areas changed under the combined action of natural resource endowment,social and economic conditions and other internal and external factors.As a result,the agricultural production function could not replace the economic development function and become the function of rural landscape production.The research results of Qingpu District showed that the agricultural production function was no longer the primary functional form,yet the economic development function became the dominant function in this area.2)Temporal and spatial analysis methods of rural landscape functions can accurately and comprehensively reflect the evolution of the characteristics of multifunction tradeoffs and synergies.According to the Spearman rank correlation analysis of the multifunction value of the rural landscape in the time dimension,the results masked the differences of resource and environment carrying capacity caused by the differences of regional landscape resource endowment in the spatial dimension.3)The spatial and temporal differences of the multi-functional tradeoffs and synergies of the rural landscape in Qingpu District from 1980 to 2018 were significant.There was significant heterogeneity of tradeoffs and synergies between functions in the spatial pattern,with clustering characteristics.Meanwhile,as for the temporal pattern,the tradeoffs and synergies of functions changed differently in terms of Moran’s I and the correlation coefficient.The results of this study can provide scientific references for urban-suburban-rural space reconstruction and regional sustainable development.

Estimating the Spatial and Temporal Changes in the Green Development Level in Beijing during 2006–2016

Green development is an important way to achieve global sustainable development goals, and has become one of the main research hotspots in recent years. Balancing economic development and environmental protection has turned out to be a great challenge in Beijing, the capital of China, which can provide some suggestions on ecological civilization construction and green development for other cities. However, there have been limited studies on this crucial topic. Therefore, based on the statistical data for Beijing from 2006 to 2016, this paper constructed the green development evaluation system of Beijing, and used the Projection Pursuit Model and spatial analysis method to analyze the spatial and temporal changes in its green development level. We also aimed to further explore the influences of key factors on green development. Our results illustrated that:(1) the overall and average levels of green development in Beijing showed significant increasing trends;(2) there are obvious spatial differences in green development among districts in Beijing, with the outer districts showing higher values;and(3) the environmental condition and human consumption were two important factors driving the green development in Beijing.

Geographical Impact and Ecological Restoration Modes of the Spatial Differentiation of Rural Social-Ecosystem Vulnerability:Evidence from Qingpu District in Shanghai

Vulnerability research is the core issue and one of the research hotspots of sustainable development science.Vulnerability and its evaluation framework provide a new perspective for rural social-ecosystem studies.This paper introduced the‘input-output’efficiency theory and constructed the‘SEE-PSR’framework for the analysis of social-ecosystem vulnerability in the rural area in Qingpu District of Shanghai City.The DEA models,spatial autocorrelation model,multivariate logistic regression model,geographical detector and hierarchical cluster model were used to analyze the spatial differences of social-ecosystem vulnerability,and its geographical impact mechanisms and ecological restorations,in 184 administrative villages in this area.The results can be divided into three main points.(1)The results of the‘input-output’efficiency model of the EW-DEA based on entropy weight aggregation crossover was more reliable and accurate for the evaluation of rural social-ecosystem vulnerability.The vulnerability of the social-ecosystems in the administrative villages showed a trend of gradual decline from east to west,with an average value of vulnerability of 0.583,and the vulnerability of social systems had become an important factor in constraining the decrease of the vulnerability of the social-ecosystems in the region.(2)The distances from the center of Shanghai City,from Dianshan Lake,from the center of Qingpu District and from the water area were the four dominant geographical factors affecting the vulnerability of the social-ecosystem in this region.The geographical impacts exhibited the spatial differentiations of systemic structure,the substitution of typological attributes and the transformation level.(3)The geographical factors coupling the impact types of the social-ecosystem vulnerability were divided spatially into 10 types.The geographic multi-factor coupling impact types were dominant,which presented multi-cyclic spatial patterns and were dominated by the central multi-factor which was surrounded by the single factor types on both sides.According to the different types,some feasible ways of ecological restoration were proposed,which drew on the experiences of integrated territory consolidation to remediate the vulnerability of rural social-ecological systems.The results of this study can provide scientific reference for rural spatial reconstruction,regional ecological restoration and sustainable development for the regions characterized by conflict in the‘strict protection of the ecological environment and vigorous development of the economy’.