一种精确农业自动变量施肥技术及其实施

该文介绍一种自制的实现精确农业自动变量施肥作业的变量施肥系统。该系统基于DGPS卫星定位原理，将GPS、GIS与DDS相结合，进行施肥作业决策，决策的施肥数据写在IC卡上。当施肥机在田间工作时，通过装备在施肥机上的GPS接收的位置数据触发存储在IC卡的施肥决策指令，用该指令通过单片机去控制施肥机上的排肥轴的转速，实现精确农业自动变量施肥作业。田间试验表明，该系统能够实现精确农业意义上的变量施肥作业。     

3S技术在农田基础地图测绘与更新中的集成应用

为了得到大比例尺、高精度、电子版的农田基础地图作为参照图层，来分析与处理精细农业研究与实践中采集到的不同数据，该文讨论了几种利用3S技术的测绘方法，并进行了GPS测绘工作。GPS定位数据在GIS系统中经过处理并编辑成图。为了提高测绘和成图的精度，文中设计并测试了单点重复定位—求平均，以及连续定位—移动平均等GPS数据的处理方法；测试结果表明测绘精度达到0.5 m左右。该文农田基础地图的更新基于经过多项式几何校正与坐标配准后的遥感图像进行。     

数字化农业气象学

随着电子信息技术的迅速发展，数字农业必然是21世纪农业的重要发展方向。数字化方法学将要渗透到农业气象学的所有领域，如作物气象、农业气候、农业气象预报、农田小气候与微气象、畜牧气象、园林气象等，使农业气象学从传统水平向现代化、数字化水平发展。数字化农业气象学将在我国的数字农业与农业现代化的进程中发挥重要作用。     

利用卫星遥感和GIS技术进行昭通地区土壤侵蚀调查研究

在分析了昭通地区土壤侵蚀成因和规律后,本研究选择了植被盖度和坡度作为确定土壤侵蚀等级的主导因子。利用1999年昭通地区TM卫星图像进行判读,提取植被盖度、土地类型和土地利用方式等信息;从地形图提取坡度信息;最后应用地理信息系统(GIS)的通用软件工具ARC/INFO7.11和AR-CVIEW3.2进行土壤侵蚀等级的空间分析,得到了土壤侵蚀等级空间分布图。根据土壤侵蚀等级图的统计分析结果对长防林(云南部分)实施后产生的生态效益尤其是土壤侵蚀的治理作出了科学评价。     

RothCUK – a dynamic modelling system for estimating changes in soil C from mineral soils at 1-km resolution in the UK

We describe the development and application of an integrated data and modelling system for estimating soil carbon (C) fluxes from mineral soils caused by changes in climate, land use and land management at 1‐km resolution in the UK (RothCUK). The system was developed with the aim of improving methods for United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol accounting and integrates national scale data sets of soil properties, land use and climate with the Rothamsted carbon model (RothC). A preliminary estimate of soil C fluxes because of land use change (LUC) over the period 1990–2000 is presented as an example application of the system. RothCUK shows LUC to be a net source of CO₂ from 1990 to 2000 although the RothC estimate was smaller (6488 kt C) than the estimate from the single exponential model (SEM) method currently used to calculate C fluxes due to LUC for the UK National Greenhouse Gas Inventory (mean: 9412 kt C). Based on previous studies, an uncertainty range in our estimates of ±50–100% seems plausible. In agreement with the SEM, RothCUK suggests that the largest single contributor to soil C fluxes from LUC was conversion of grassland to arable land. Differences between the results may be attributed to differences in the two models and the assumptions and underlying data used in making the calculations. The RothCUK system provides a powerful method for estimating changes in soil C stocks, enabling areas and management systems with particularly large changes in soil C stocks to be located at fine resolution.     

ASSESSING LANDSLIDE SUSCEPTIBILITY BY INCORPORATING THE SURFACE COVER INDEX AS A MEASUREMENT OF VEGETATIVE COVER

Local environmental conditions are known to be the most influential in landslide dynamics. Some variables, such as slope, elevation, lithology, vegetative cover, and soil type, are more common and influential than others. Every variable, except for vegetative cover, has been incorporated into many different statistical models as a continuous variable showing nuances and differentiation among the data. In regions where vegetative cover is the single most important variable in determining slope stability, a land cover classification cannot provide the level of information required for efficient modeling of landslide events. It is hoped that the surface cover index (SCI) can be used to numerically assess vegetative cover by using Landsat imagery and sub‐pixel analysis. Two models utilizing simple raster calculations involving slope and the SCI were created. Each model was then assessed and validated for accuracy by using a user‐created multi‐temporal landslide inventory of the Dominical, Costa Rica area. Results determined that normalized inputs of slope and SCI can produce an algorithm with a high degree of accuracy and proved that the SCI can be used in assessing landslide hazard in a tropical forest environment. Copyright © 2011 John Wiley & Sons, Ltd.     

黄土塬区复合型生态农业土地生产力评价

应用GIS技术,对专题图件进行叠加处理后,将西坡村土地归并划分为39个生产力单元,并利用修正后的生产力指数(PI)模型和投入产出方法得出其潜在生产力与现实生产力。通过比较后得到总的趋势是生产力指数(PI)值高的地块其现实生产力也高;反之,生产力指数(PI)值低的地块其现实生产力也低,二者的相关系数为0.6563。同时,二者均呈现出塬面较高,坡面较低的规律。在塬面上高值地块靠近农村居民点,地面平缓、土地肥力高。坡面上阴坡地块的一般要高于阳坡地块。总体上,该村的土地利用基本符合自然经济规律,但也存在一定的问题需要改进。     

基于GIS技术的新疆棉花施肥专家系统

对集成地理信息系统(GIS)技术应用于新疆棉花施肥专家系统(ES)进行了研究和探讨,通过Internet访问该专家系统界面, 用户可以得到农田地块的地理信息,进行棉田施肥推荐;同时可进行农田肥力的综合查询和专题图制作。该专家系统的建立不仅推进了新疆地区平衡施肥信息化的进程,也为精准农业的实践提供决策支持。     

基于GIS技术的上海精准农业水稻生产潜力估算模型——考虑土壤肥力空间差异的影响

基于精准农业精细与准确的原则,利用层次分析法与模糊数学相结合的方法,详细分析了试验区土壤肥力的空间分布情况,并将其作为水稻生产潜力差异的主要影响因素。此外再综合考虑光、温、水等因素的影响,分别计算了光合潜力、光温潜力、气候———生物潜力及各采样点的农业自然生产潜力。推算结果通过了实际资料的验证,生产潜力与当年水稻实际产量达到显著相关水平。同时根据农业自然生产潜力值绘制了空间分布图,根据图上各点所能实现的产量,可以确定具体的施肥量,对田间定点、定量施肥具有很好的指导意义,避免等同施肥造成的肥料浪费,降低对环境的污染。     

艾比湖地区30多年来土壤侵蚀时空变化规律研究

以遥感与GIS为技术支撑,对新疆艾比湖地区1972-2005年土壤侵蚀进行了动态监测,并对33年来土壤侵蚀时空变化进行分析.研究结果表明.艾比湖地区的土壤侵蚀以风蚀为主.水蚀面积变化不大,风蚀区各强度面积变化明显.其时空变化特征:(1)侵蚀面积1977-2005年总体呈下降趋势,其中1992-2001年侵蚀面积减少显著,且以轻度和强度风蚀减少为主;其次是2001-2005年侵蚀面积减少明显.以中度和轻度风蚀减少为主.只有1972-1977年侵蚀面积有所增加.(2)侵蚀变化速度1977--2005年呈现总体下降,而且1990-2005年下降的速度趋快.(3)侵蚀强度趋于下降.水蚀各强度等级变化很小.风蚀各强度等级变化明显,以强度高的类型向强度较低类型转换为主.究其原因主要是20世纪90年代以来,由于艾比湖水面持续增大和国家一系列生态保护与建设工程的实施,使艾比湖周边风力侵蚀得到有效遏制,区域生态环境明显改善.