基于生态适宜度模型的城乡土地利用分区与优化布局——以鄱阳湖生态经济区为例

开展城乡土地利用功能分区和空间布局优化,是促进城乡一体化发展的有效途径。以鄱阳湖生态经济区为例,通过构建城乡土地利用生态位适宜度模型,对鄱阳湖生态经济区土地利用生态位适宜度进行了分区,并在此基础上提出了优化布局策略。结果表明:(1)鄱阳湖生态经济区布局优化为商业发展主导区、工业发展主导区和农业发展主导区以及环境保护主导区;(2)鄱阳湖生态经济区城乡土地利用空间布局可划分为核心增长极、区域中心城市、一级扩散圈、二级扩散圈和二级扩散带;(3)应从发展高新技术产业、提升都市圈核心竞争力、保障城乡用地需求、加快农田水利建设和优化生态开发利用模式等方面优化城乡土地利用空间布局。基于生态适宜度模型探讨城乡土地利用布局,为实现区域城乡均衡发展提供了新视角。     

小麦专用肥在河南省典型地区的应用效果研究

河南省小麦单产和总产均居全国首位,然而当地农户施肥量大,且偏施氮肥、忽视磷钾肥现象严重,导致肥料利用率和经济效益较低.为解决这些施肥问题,依据河南省土壤养分供应状况和小麦营养需求规律,并考虑大、中、微量元素养分形态配伍和协同增效,优化肥料配方和生产工艺,开发小麦专用复合肥料,于2017-2018年在河南禹州进行小区试验...     

不同砧木嫁接对西瓜抗病性及主要经济性状的影响

将引进的日本强势葫芦、勇士野生西瓜等7个西瓜嫁接砧木分别与本地主栽的西瓜品种早佳84-24进行嫁接试验。通过对嫁接亲和力,嫁接苗的抗枯萎病能力、产量和品质等主要性状的考查分析,结果表明以日本强势葫芦作砧木的嫁接苗综合性状表现最佳。     

Irrigation scheduling strategies for cotton to cope with water scarcity in the Fergana Valley, Central Asia

The Central Asian countries face high water scarcity due to aridity and desertification but excess water is often applied to the main irrigated crops. This over-irrigation contributes to aggravate water scarcity problems. Improved water saving irrigation is therefore required, mainly through appropriate irrigation scheduling. To provide for it, after being previously calibrated and validated for cotton in the Fergana region, the irrigation scheduling simulation model ISAREG was explored to simulate improved irrigation scheduling alternatives. Results show that using the present irrigation scheduling a large part of the applied water, averaging 20%, percolates out of the root zone. Several irrigation strategies were analyzed, including full irrigation and various levels of deficit irrigation. The analysis focused a three-year period when experiments for calibration and validation of the model were carried out, and a longer period of 33 years that provided for an analysis considering the probabilities of the demand for irrigation water. The first concerned a wet period while the second includes a variety of climatic demand conditions that provided for analyzing alternative schedules for average, high and very high climatic demand. Results have shown the importance of the groundwater contribution, mainly when deficit irrigation is applied. Analyzing several deficit irrigation strategies through the respective potential water saving, relative yield losses, water productivity and economic water productivity, it could be concluded that relative mild deficits may be adopted. Contrarily, the adoption of high water deficit that produce high water savings would lead to yield losses that may be economically not acceptable.     

Water management and crop production for food security in China: A review

Food security is a high priority issue on the Chinese political agenda. China’s food security is challenged by several anthropogenic, sociopolitical and policy factors, including: population growth; urbanization and industrialization; land use changes and water scarcity; income growth and nutritional transition; and turbulence in global energy and food markets. Sustained growth in agricultural productivity and stable relations with global food suppliers are the twin anchors of food security. Shortfalls in domestic food production can take their toll on international food markets. Turbulence in global energy markets can affect food prices and supply costs, affecting food security and poverty. Policy safeguards are needed to shield food supply against such forces. China must make unremitting policy responses to address the loss of its fertile land for true progress towards the goal of national food security, by investing in infrastructure such as irrigation, drainage, storage, transport, and agricultural research and institutional reforms such as tenure security and land market liberalization. The links between water and other development-related sectors such as population, energy, food, and environment, and the interactions among them require reckoning, as they together will determine future food security and poverty reduction in China. Climate change is creating a new level of uncertainty in water governance, requiring accelerated research to avoid water-related stresses.     

汽车动力总成CAN总线系统的设计及其评价

根据CAN总线系统的各组成部分,设计了某型汽车动力总成CAN总线系统,并在此基础上,依据评价指标,采用直接测试法,验证了CAN总线系统设计方案的可行性和可靠性,并已应用于某型汽车上。     

Growth overfishing in the brown shrimp fishery of Texas, Louisiana, and adjoining Gulf of Mexico EEZ

Growth overfishing in the brown shrimp, Farfantepenaeus aztecus, fishery in inshore (estuarine) and offshore (Gulf of Mexico) territorial waters of Texas and Louisiana, and adjoining waters of the United States’ (U.S.) Exclusive Economic Zone (EEZ), and its potentially detrimental economic consequences to the harvesting sector, have not been among major concerns of Federal and State shrimp management agencies. Three possible reasons include (1) environmentally influenced variations in recruitment that cause wide fluctuations in annual landings, which tend to obscure effects of fishing, (2) competition between inshore and offshore components of the harvesting sector, and (3) partitioning of management jurisdiction among a Federal council and two State agencies. Wide variations in landings led to beliefs that high levels of fishing mortality were tolerable and recruitment overfishing was of no major concern. This encouraged somewhat laissez-faire management approaches that allowed fishing effort to increase over the years.Our objectives were to determine whether growth overfishing occurred in this fishery during 1960–2006, and whether and how decreases in size of shrimp within the landings, in response to increases in fishing effort, affected inflation-adjusted annual (calendar year) ex-vessel value of the landings, i.e., their value to the harvesting sector. Growth overfishing occurred in the early 1990s, and then abated as fishing effort declined due to rising fuel costs and competition from imported shrimp. However, inflation-adjusted annual ex-vessel value of the landings peaked in 1985, prior to growth overfishing.Management actions implemented in 2001 for Texas’ territorial waters, and in the EEZ off Texas and Louisiana in 2006, should limit future fleet expansion and increases in fishing effort, thereby reducing the chances of growth overfishing and its potentially detrimental economic impacts on the harvesting sector. Growth overfishing should be included among the guidelines for future management of this brown shrimp fishery.     

农村居民点整理潜力转化耕地经济限制性研究

就农村居民点整理潜力转化为耕地的经济限制性进行研究。从经济可行性评价入手,构建指标体系,采用多指标综合评价法、层次分析法与专家咨询法,测算研究区经济适宜性评分,确定研究区农村居民点整理潜力转化为耕地的经济限制性,得出各区县整理潜力转化为耕地的经济限制性修正系数。研究结果表明,天津市农村居民点整理潜力转化为耕地的经济限制性可分为3 个类别：（1）无经济限制性区县,1≥a 经≥0.6,包括西青区、北辰区、东丽区3 个区县;（2）有一定经济限制性区县,0.6＞a 经≥0.3,包括塘沽区、津南区、武清区、宁河区、汉沽区、大港区6 个区县。（3）经济限制性较大区县,0.3＞a 经≥0,包括蓟县、宝坻区、静海区3 个区县。各区县农村居民点整理潜力转化耕地的经济限制性在多经济因素影响下差别很大。     

长江中游不同玉稻种植模式产量及资源利用效率的比较研究

发展长江中游玉米生产是解决本区域玉米产需矛盾的根本途径。近年来随着长江中游玉米的快速发展,该地区出现了春玉米–晚稻、双季玉米和早稻–秋玉米等新型的一年两熟制种植模式,为探明其适应性和实用性,2013—2014年在湖北省武穴市设置了传统种植的双季稻(对照)、春玉米–晚稻、双季玉米和早稻–秋玉米共4种两熟制种植模式,分析比较其周年产量及光、温、水资源利用效率和经济效益。结果表明,春玉米–晚稻和双季玉米周年产量显著高于早稻–秋玉米和双季稻。与双季稻相比,春玉米–晚稻周年产量、光能生产效率、光能利用率、积温生产效率、水分利用率及经济效益分别提高18.3%、14.1%、23.4%、16.4%、37.2%和44.3%,双季玉米分别提高了13.5%、8.1%、26.1%、11.4%、88.8%和37.8%。春玉米其产量、积温生产效率、水分利用率及经济效益两年平均比早稻分别高出30.6%、29.5%、57.2%和96.1%,而秋玉米和晚稻之间产量无显著差异。不同玉稻模式周年产量差异主要源于第一季春玉米和早稻产量的差异。可见,春玉米–晚稻和双季玉米是适宜在长江中游推广的两熟制种植模式。     

基于平稳小波变换的冬小麦覆盖度高光谱监测

在2010与2011年度冬小麦生长季,通过大田小区试验,实测了冬小麦冠层的高光谱反射率与覆盖度。分析了不同覆盖度下的冬小麦冠层光谱特征以及不同生育期冬小麦冠层光谱反射率与覆盖度的相关性,建立了基于归一化植被指数(NDVI)与比值植被指数(RVI)、小波能量系数的不同生育期冬小麦覆盖度估算模型。结果表明:覆盖度越大,冬小麦光谱反射率在可见光波段越小,在近红外波段越大。在可见光波段,光谱反射率与覆盖度负相关,在"红边"处,由负相关变成正相关。在返青期、拔节期,NDVI估算效果好(R2为0.835 9、0.805 7);在抽穗期、灌浆期,RVI估算效果好(R2为0.803 1、0.829 4)。在返青期、拔节期、抽穗期、灌浆期,以高频、低频小波能量系数为自变量的冬小麦覆盖度估算模型的R2分别达到0.911 2、0.895 4、0.880 2、0.927 5。