有机蔬菜产业园的水平衡分析——以南京地区为例

导读：世界有机农业发展呈现七大优势：一是由单一、分散、自发的民间活动转向全球性的农业运动;二是由关心环保到关注环保和食品安全;三是由绿色食品扩大到绿色产品;四是有机食品认证国际化;五是从事有机农业的农场数量空间增加;六是由区域性布局转向全球性布局;七是销售渠道多元化。由此为我们发展和生产绿色蔬菜提供了机遇,有机蔬菜产业园需严格按照相关标准建设,其中对水源质量的要求也很高,有机蔬菜产业园区域内部集蓄的雨水是有机农业灌溉用水的首选。     

基于水质改善功能下的古护城河景观改造分析——以西安护城河为例

通过运用景观的能力,使护城河景观得到改善,力求生态水景观、植被景观和人文景观的融合。基于水质改善功能前提下更好地改造和提升古护城河景观,打造以历史文化、绿色生态、休闲娱乐为一体的生态旅游区。     

不同控释氮肥用量对秋季大白菜产量与氮肥农学效率的影响——以桂中地区为例

大白菜是喜氮作物,氮肥用量的多少直接影响其产量与效益。为探索桂中地区大白菜的平衡施肥技术,2008年开展大白菜的不同控释氮肥用量试验研究。结果表明:施氮水平为1395kg/hm2时大白菜产量较高,为142500kg/hm2;施氮水平为930kg/hm2时大白菜的农学效率较高,为7.89kg/kg。可见,氮肥施用范围为930～1395kg/hm2时,桂中地区大白菜的经济、生态效益比较理想。     

循环经济视域下秸秆综合利用的SWOT分析及对策——以重庆市南川区秸秆综合化利用为例

结合重庆市南川区的实际，分析该区秸秆综合利用的优势（Strength）与劣势（Weakness）以及外部环境的机会（Opportunity）与威胁（Threat），提出相应的对策。     

贵州雷公山区花魔芋种植的适生环境条件分析

根据花魔芋生长发育的基本要求,对照雷公山区的气候资料和土质报道,指出雷公山区海拔600~1 500 m区域的生态环境适合花魔芋种植,其中600~900 m、900~1 300 m、1 300~1 500 m依次为次适层、最适层和可适层;深入研究抗耐酸土魔芋种质发现,就近选择凉爽场地扩繁、轮繁种子,能更好适应基地建设就地供种要求;只有应对好酸土锈田、缺磷少钾、春秋低温、凝冻霜害、连作障碍的不利影响,拓展间作、套作,魔芋基地才能有望稳步扩大并实现高产优质。     

Fuzzy k-means classification of topo-climatic data as an aid to forest mapping in the Greater Yellowstone Area, USA

Previous attempts to quantify topographic controls on vegetation have often been frustrated by issues concerning the number of variables of interest and the tendency of classification methods to create discrete classes though species have overlapping property sets (niches). Methods of fuzzy k-means classification have been used to address class overlap in ecological and geographical data but previously their usefulness has been limited when data sets are large or include artefacts that may occur through the derivation of topo-climatic attributes from gridded digital elevation models. This paper presents ways to overcome these limitations using GIS, spatial sampling methods, fuzzy k-means classification, and statistical modelling of the derived stream topology. Using data from a ca. 3600 km² forested site in the Greater Yellowstone Area, we demonstrate the creation of meaningful, spatially coherent topo-climatic classes through a fuzzy k-means classification of topo-climatic data derived from 100 m gridded digital elevation models (DEMs); these classes were successfully extrapolated to adjacent areas covering a total of ca. 10000 km². Independently derived land cover data and middle infrared corrected Landsat TM derived estimates of Normalised Difference Vegetation Index (M_NDVI) at 575 independently sampled sites were used to evaluate the topo-climatic classes and test their extrapolation to the larger area. Relations between topo-climatic classes and land cover were tested by ² analysis which demonstrated strong associations between topo-climatic class and 11 of the 15 cover classes. Relations between M_NDVI and topo-climatic classes proved to be stronger than relations between M_NDVI and the independent cover classes. We conclude that the fuzzy k-means procedure yields sensible and stable topo-climatic classes that can be used for the rapid mapping of large areas. The value of these methods for quantifying topographic controls on biodiversity and the strength of their relations with computed NDVI values warrant further investigation.     

Paleoecological and paleolandscape modeling support for pre-Columbian burning by Native Americans in the Golden Trout Wilderness Area,California, USA

Landscape Ecology - Though people have used fire to alter landscapes across North America for millennia, there remains a debate whether Native Americans altered California’s mountainous...