成都郊区农业土地利用空间集聚及斑块变化特征分析

【目的】应用时空大数据分析近年来成都郊区典型农业乡镇的农业土地利用变化的特征,为开展乡镇农业土地利用评估、农业产业结构调整优化和乡村振兴提供信息支撑。【方法】文章使用Sentinel-2A多光谱影像、Google Earth高分辨率真彩色合成影像和WorldView-2影像相结合的数据源,提取研究区农业空间土地利用信息,通过莫兰指数、热点分析和景观格局指数分析农业土地利用变化特征。【结果】(1)园地较其他类型的聚集效应明显,呈现典型热点和冷点区域,其中热点主要分布于研究区西部的丘陵区域,冷点区域分布于东部的平原区域。(2)土地利用斑块变化指数表明耕地、园地和设施农用地变化明显,耕地平均面积减少,园地和设施大棚平均面积显著增加。【结论】郊区乡村地区农业土地利用及作物用地类型存在显著聚集效应,粮油种植业则随着其他作物、大棚及水产养殖等产业发展,聚集效应逐步下降。农业用地逐步由单一粮油产业主导转为粮油、蔬菜、水果、水产养殖等多元结构,土地斑块特征受农业产业的规模化、专业化程度发展影响明显。     

基于农户土地利用目标差异的农用地利用变化机制研究

研究农用地利用变化驱动机制是破解土地利用变化规律及其效应的关键.本文从农用地利用单元和农户土地利用单元特征分析入手,得出农户的土地利用目标需求和农用地的供给能力之间存在偏差是农户土地利用微观变化的根本诱因,基于此可以将农户分为粮食需求型、利润需求型、粮食和利润协调型三种类型.进而在探讨农户土地利用影响因素的基础上,提出农用地利用变化驱动机制框架,构建基于土地产权约束、农用地用途约束下的农户土地利用单元和农地利用单元相互影响的概念框架,并基于农户收益最大化原则对农户家庭的劳动力的分配进行经济学解释.     

农用地土壤环境损害鉴定评估中的基线水平研究

针对农用地土壤环境损害鉴定评估缺乏统一规范、科学合理、操作性强的技术标准等问题,从外部因素、时间属性、内在状态等方面诠释了土壤基线水平的内涵特征;从来源、构成等方面构建了农用地土壤基线水平指标体系;从资料收集、现场调查、监测采样、专家咨询等途径分析了农用地土壤基线水平信息的获取方法;从基于时间参比的背景值或本底值、基于空间参比的对照值、基于统一尺度的标准值或基准值、基于生态风险的剂量/强度-效应值和基于头脑风暴的专家判定值等方面比较了5种农用地土壤基线水平值的特点和适用情形,并提出了农用地基线水平优先顺序的确定程序与方法,最后对未来土壤基线水平研究提出了展望。     

Suitability of common models to estimate hydrology and diffuse water pollution in North-eastern German lowland catchments with intensive agricultural land use

Various process-based models are extensively being used to analyze and forecast catchment hydrology and water quality. However, it is always important to select the appropriate hydrological and water quality modeling tools to predict and analyze the watershed and also consider their strengths and weaknesses. Different factors such as data availability, hydrological, hydraulic, and water quality processes and their desired level of complexity are crucial for selecting a plausible modeling tool. This review is focused on suitable model selection with a focus on desired hydrological, hydraulic and water quality processes (nitrogen fate and transport in surface, subsurface and groundwater bodies) by keeping in view the typical lowland catchments with intensive agricultural land use, higher groundwater tables, and decreased retention times due to the provision of artificial drainage. In this study, four different physically based, partially and fully distributed integrated water modeling tools, SWAT (soil and water assessment tool), SWIM (soil and water integrated model), HSPF (hydrological simulation program– FORTRAN) and a combination of tools from DHI (MIKE SHE coupled with MIKE 11 and ECO Lab), have been reviewed particularly for the Tollense River catchment located in North-eastern Germany. DHI combined tools and SWAT were more suitable for simulating the desired hydrological processes, but in the case of river hydraulics and water quality, the DHI family of tools has an edge due to their integrated coupling between MIKE SHE, MIKE 11 and ECO Lab. In case of SWAT, it needs to be coupled with another tool to model the hydraulics in the Tollense River as SWAT does not include backwater effects and provision of control structures. However, both SWAT and DHI tools are more data demanding in comparison to SWIM and HSPF. For studying nitrogen fate and transport in unsaturated, saturated, and river zone, HSPF was a better model to simulate the desired nitrogen transformation and transport processes. However, for nitrogen dynamics and transformations in shallow streams, ECO Lab had an edge due its flexibility for inclusion of user-desired water quality parameters and processes. In the case of SWIM, most of the input data and governing equations are similar to SWAT but it does not include water bodies (ponds and lakes), wetlands and drainage systems. In this review, only the processes that were needed to simulate the Tollense River catchment were considered, however the resulted model selection criteria can be generalized to other lowland catchments in Australia, North-western Europe and North America with similar complexity.     

土地利用变化对农业文化遗产系统结构的影响——以浙江省德清县为例

德清县是中国重要农业文化遗产——德清淡水珍珠传统养殖与利用系统的所在地,20多年来,在快速的城镇化进程中,德清县土地利用方式发生了较大变化。为刻画近年来德清土地利用变化特征,揭示其对农业文化遗产系统结构产生的影响,本研究基于访谈资料、第三次国土资源调查数据以及GlobeLand 30土地利用数据等进行了分析。结果表明,德清县在产业结构升级与城镇化扩张推动下,自2005年到2020年建设用地增加了53.36 km²,耕地减少了62.33 km²;在环境治理政策、经济效益和多种技术的综合作用下,养殖水面的面积快速增加,15年内共增长了117.75 km²;但桑地因经济效益不佳,1992年到2019年间面积减少了19.76 km²。在空间分布上,变化主要集中在东部水网平原区,这也是德清淡水珍珠传统养殖与利用系统所在地。研究显示,土地利用方式的转变,改变了当地“粮桑鱼畜”这一传统生态农业景观的结构及其背后的生态过程,减弱了不同土地利用方式之间的物质能量流动与循环,使得遗产系统面临较大的威胁。未来应进一步提高...     

广西LUCC过程与气候波动对农田生产潜力的影响

【目的】分析近20年广西土地利用／土地覆盖变化（Land Use and Land Cover Change,LUCC）过程与气候波动对农田生产潜力的影响。【方法】基于20世纪80年代末至2010年的5期土地利用遥感监测数据,分析近20年广西耕地资源的变化过程;结合1990～2010年的逐日气象资料,采用环境因子逐步订正方法估算农田生产潜力。【结果】根据遥感监测结果,近20年广西耕地面积净减少了20843．81ha。在1990～2010年平均气候条件下,广西林地变耕地动态对农田生产潜力总值增加贡献最大,占新开垦耕地农田生产潜力总值的80．73％;耕地变建设用地动态使农田生产潜力总值减少最多,占流失耕地农田生产潜力总值的74．39％。当耕地保持20世纪80年代末状态不变时,气候波动使1990-2010年广西水田生产潜力均值变化总体上呈上升趋势,但旱地生产潜力均值变化总体上呈下降趋势。【建议】广西新开垦耕地的农田生产潜力不及流失耕地的农田生产潜力,优质耕地面积减少。因此要求在强调耕地占补平衡的同时,注重耕地质量的平衡,一方面要防止优质耕地面积的减少,另一方面要通过改土改水、节水灌溉等措施提高粮食综合生产能力,弥补由优质耕地减少和气候变化给粮食产量带来的损失。