卫星遥感提取烟田种植面积应用分析

烟草是中国重要的经济作物之一,准确提取烟草种植面积对农作物种植结构调整、烟田科学管理和监测具有重要意义。笔者基于GEE(Google Earth Engine)云平台,利用2021年2—11月Sentinel-2A多时相数据,根据烟草种植特性排除误差因子,并结合实地采样数据的分布特征归纳植被特征,利用阈值法,以山东省临沂市为例,开展烟田种植地块自动提取的研究。结果表明,采用GEE和随机森林算法组合模式,能够准确获得烟田种植的空间分布信息,总体分类精度为96.04%。本研究方法分类质量较高,可以满足研究需要,为烟田种植管理部门提供准确、快捷、科学的参考。     

基于多时相MODIS数据监测水、旱作物种植面积及空间分布

针对农业信息服务中大范围水田、旱田种植面积信息调查业务的现状与需求,以黑龙江省为研究区,通过分析水田、旱田作物发育期特征、MODIS数据植被指数(NDVI、EVI、LSWI)时序特征,引入积温条件分区构建决策规则,提取检测农田与其他、水田与旱田作物种植的空间分布.以实地调查地面验证点对分类结果进行验证,结果表明,分类结...     

基于关键期HJ卫星数据提取无棣县作物种植面积

探讨利用作物关键生育期HJ卫星遥感数据,进行区域主要作物种植面积快速监测的可行性,旨在建立一种方便快捷的作物种植面积提取技术。以山东省无棣县为研究区,根据该县作物栽培技术月历为参考选择关键期HJ星遥感数据,通过EVI指数时序数据分析,采用支持向量机(SVM)方法进行了该县主要作物种植空间分布信息提取。结果表明：关键期HJ星EVI指数数据结合SVM方法,能较为准确地获取该县冬小麦、玉米和棉花的种植面积,总体的面积总量精度超过93%,空间分布精度大于75%;利用关键期影像大大减少了数据处理量,便于可视化感兴趣区的选择,仅利用SVM方法就获得了满足精度要求的作物面积提取结果,大大简化了操作流程,为其他区域利用HJ卫星数据提取作物种植面积提供了参考。     

HJ卫星数据在棉花种植面积提取中的应用研究

 探索利用环境小卫星数据进行棉花种植面积的提取,旨在利用国产卫星数据建立一种方便快捷的棉花种植面积提取技术,为棉花的遥感估产奠定基础;选取2011年新疆北部国营农场棉花不同生育期内两期HJ卫星影像,根据棉花与研究区其他作物物候和光谱差异性、农作物生长规律,运用监督分类算法、密度分割和逻辑运算,辅助于人机交互的目视解译,得到研究区棉花种植面积;结果表明：不同监督分类算法中,神经网络分类法和最大似然法分类效果最佳;最终提取的棉花面积总体精度为87.7%;本文采用的方法较为实际、便捷,提取棉花种植面积的精度符合农场生产要求,可为棉花估产和作物种植结构分析提供科学依据。     

基于高光谱数据提取作物冠层特征信息的研究进展

高光谱(Hyperspectral)遥感是指光谱分辨率在10-2λ的遥感信息,其特点是光谱分辨率高(5~10nm)、波段连续性强(在0.4~2.5μm范围内有几百个波段)。高光谱遥感器既能对目标成像(有时也称成像光谱遥感)、又能测量目标物的波谱特性,因此,它不仅可以用来提高对农作物和植被类型的识别能力,而且还可以用来监测农作物长势和反演农作物的理化特性。绿色植物具有独特的光谱曲线特征,而作物具有绿色植物典型的光谱特征曲线,基于作物的光谱特征研究与其生理生化特性之间的关系,高光谱遥感数据在提取作物生理生化特征、提取作物冠层信息、估产以及预测病虫害等许多方面都表现出巨大的应用潜力。本文概述了利用高光谱数据提取作物冠层信息的研究现状、展望及其在新疆棉花生产中的应用和前景。     

基于GEE云平台与Sentinel数据的高分辨率水稻种植范围提取——以湖南省为例全文替换

准确获取大范围的水稻种植空间分布信息对调整农业生产结构和保障粮食安全至关重要。本文以湖南省为研究区,基于谷歌地球引擎(Google Earth Engine, GEE)云平台,协同Sentinel-1 SAR和Sentinel-2 MSI数据,根据水稻物候期极化(vertical transmit/horizontal receive, VH)后向散射系数、增强型植被指数(enhanced vegetation index, EVI)的变化特征构建水稻提取决策树模型,开展高分辨率水稻种植范围遥感提取,并进行精度验证。结果表明:本模型能够准确实现多云多雨地区的水稻种植范围遥感制图;基于混淆矩阵计算水稻总体分类精度为93.97%,Kappa系数为0.908,单、双季稻F1-score均超过91%,可为亚热带多云雨且稻田破碎分布区的水稻种植范围遥感提取提供参考。湖南省水稻分布受地形和气温的影响明显,主要分布在海拔200 m以下,坡度小于6°,年均气温大于17℃的区域;双季稻集中分布在岳阳、常德和益阳市,而单季稻种植分布相对零散。     

Spatial and temporal uncertainty of crop yield aggregations

The aggregation of simulated gridded crop yields to national or regional scale requires information on temporal and spatial patterns of crop-specific harvested areas. This analysis estimates the uncertainty of simulated gridded yield time series related to the aggregation with four different harvested area data sets. We compare aggregated yield time series from the Global Gridded Crop Model Intercomparison project for four crop types from 14 models at global, national, and regional scale to determine aggregation-driven differences in mean yields and temporal patterns as measures of uncertainty.The quantity and spatial patterns of harvested areas differ for individual crops among the four data sets applied for the aggregation. Also simulated spatial yield patterns differ among the 14 models. These differences in harvested areas and simulated yield patterns lead to differences in aggregated productivity estimates, both in mean yield and in the temporal dynamics.Among the four investigated crops, wheat yield (17% relative difference) is most affected by the uncertainty introduced by the aggregation at the global scale. The correlation of temporal patterns of global aggregated yield time series can be as low as for soybean (r = 0.28).For the majority of countries, mean relative differences of nationally aggregated yields account for 10% or less. The spatial and temporal difference can be substantial higher for individual countries. Of the top-10 crop producers, aggregated national multi-annual mean relative difference of yields can be up to 67% (maize, South Africa), 43% (wheat, Pakistan), 51% (rice, Japan), and 427% (soybean, Bolivia). Correlations of differently aggregated yield time series can be as low as r = 0.56 (maize, India), r = 0.05 (wheat, Russia), r = 0.13 (rice, Vietnam), and r = −0.01 (soybean, Uruguay). The aggregation to sub-national scale in comparison to country scale shows that spatial uncertainties can cancel out in countries with large harvested areas per crop type. We conclude that the aggregation uncertainty can be substantial for crop productivity and production estimations in the context of food security, impact assessment, and model evaluation exercises.     

生物质炭对土壤性状和作物产量的影响

摘要： 秸秆还田产生了很好的经济效益,但仍存在问题。因此,提出秸秆炭化还田或利用,以提高秸秆综合利用率。为此,本文综述了秸秆炭化形成的生物量炭（biomass charcoal）对土壤性状和作物产量的影响。生物量炭化后与木炭相似,耐降解,可提高土壤碳库容量,减少温室气体排放。同时炭具有很大的表面积,持水性、吸附性均较强。在一定量下,施炭可增加土壤阴、阳离子交换量、吸附氮、磷及矿物离子,减少养分损失,在一定范围内,普遍能增加作物生物量和产量,因此认为秸秆炭化还田或利用是秸秆综合利用的优势途径。     

基于NOAA/AVHRR数据的天津地区净初级生产力时空格局分析

本文基于CASA模型,充分考虑植被覆盖类型对光能利用率的影响及植被反照率对净辐射的影响,利用NOAA/AVHRR 1B卫星资料和气象资料估算了天津地区的植被净初级生产力（NPP）。估算结果表明：2007年天津地区植被NPP为3.86×109 gC/a,年平均NPP为335 gC/m2/a;蓟县、宁河与宝坻年NPP估算值居前三位;各季度对NPP总量贡献率依次为：夏季（62％）,秋季（21％）、春季（16％）,冬季（1％）;受物候和气候因素的综合影响,天津地区NPP具有明显的年际变化,利用年均NDVI可以较好地模拟天津地区NPP年总量,其模拟表达式为：     

多指标优选丹参提取工艺研究

优选丹参中丹酚酸B和丹参酮类的最佳提取工艺。以丹酚酸B和丹参酮类包括丹参酮ⅡA、丹参酮Ⅰ和隐丹参酮为综合评价指标,采用单因素试验和正交试验考查溶剂体积分数、溶剂倍数、提取温度、提取时间对提取工艺的影响。最佳提取条件为6倍量70%乙醇在80℃下提取3次,每次2 h。稳定性研究和中试验证结果表明所得工艺合理可行,可作为丹参中丹酚酸B和丹参酮类的提取工艺。     

提取方法对饲用苎麻绿原酸和总黄酮提取效率的影响

为了研究提取方法对饲用苎麻绿原酸和总黄酮提取效益的影响,笔者采用真空冷冻干燥和热风干燥2种不同的干燥提取方法,对‘湘饲苎X1’和宁远苎麻的各部位器官进行了绿原酸和总黄酮的定量提取。分析得率差异表明:无论是绿原酸还是总黄酮,‘湘饲苎X1’和宁远苎麻不同部位器官的测定含量,均表现为真空冷冻干燥样品明显高于热风干燥。在真空冷冻条件下,‘湘饲苎X1’的营养根、叶片、地下茎和茎的绿原酸测定含量提高幅度都大于100%,各器官总黄酮测定含量提高幅度也超过了1倍,且茎提高了6.08倍。宁远苎麻在真空冷冻干条件下,叶、地下茎、营养根、茎中绿原酸和总黄酮测定含量也都大幅提高。由此可见,在饲用苎麻药理成分含量的提取工艺上,真空冷冻干燥方式明显优于热风干燥方式。     

丁香油树脂的提取及稳定性研究

研究丁香油树脂的提取及稳定性。在乙醇体积分数为75%,提取温度为80℃的条件下,丁香精油树脂的最佳提取时间为120min,丁香与乙醇的比(g∶mL)为1∶6.5,提取液的pH值为7。丁香油树脂中加入0.6%的Span—80和0.2%的黄原胶并均质,可使油树脂获得大于120d的稳定时间。     

Effects of biogas digestion of clover/grass-leys, cover crops and crop residues on nitrogen cycle and crop yield in organic stockless farming systems

The trend towards specialization in conventional farming led to large agricultural areas in Germany and in Europe lacking livestock. Also stockless organic farming has increased during recent years. In organic farming clover/grass-ley (CG) provides nitrogen (N) to the whole cropping system via symbiotic N₂ fixation and also controls certain weeds. A common practice in organic farming, when ruminants are not present, is to leave the biomass from CG in the field for their residual fertility effect. CG biomass, crop residues (CR) and cover crops (CC) represent a large unexploited energy potential. It could be used by anaerobic digestion to produce biogas. A field experiment was carried out by implementing a whole cropping system with a typical crop rotation for such farming systems on the research station Gladbacherhof from 2002 to 2005. The crop rotation consisted of six crops (two legumes and four non-legume crops). The aim was to evaluate whether the use of N could be improved by processing biomass from CG, CR and CC in a biogas digester and using the effluents as a fertilizer, compared to common practice. In the control treatment, represented by the usual stockless system, the CG, CR and CC biomass were left on the ground for green manure purposes. In the biogas systems these substrates were harvested for digestion in a biogas plant. The effluents of digestion were used to manure the non-legumes in the same crop rotation. Results indicate that digestion of CG, CR and CC can increase the crop dry matter and N yields and the N content of wheat grains in organic stockless systems. Harvesting and digestion of residues and their reallocation after digestion resulted in a better and more even allocation of N within the whole crop rotation, in a higher N input via N₂ fixation and lower N losses due to emissions and probably in a higher N availability of digested manures in comparison to the same amounts of undigested biomass.     

绿原酸提取纯化及检测方法的研究进展

绿原酸具有抗菌、抗病毒、解热、升高白细胞、保肝利胆、免疫调节、抗肿瘤、降血压、降血脂、清除自由基等生理活性和药理活性。通过分析比较已报道的绿原酸的提取、分离纯化和检测方法,综述了近年来绿原酸研究方面的最新进展,为更好利用和发展绿原酸制品,实现其工业化生产提供一些参考和借鉴。     

遏蓝菜神经酸的提取与微乳化作用研究

采用索氏提取法提取遏蓝菜油,以遏蓝菜油为油相,司盘-80为表面活性剂,丙二醇为助表面活性剂,研究不同体积比km值(V_(丙二醇):V_(司盘-80))对遏蓝菜油微乳液微乳区大小的影响,并用拟三元相图和显微摄影分析试验结果。结果表明,遏蓝菜籽的含油率为19.11%～21.37%。微乳液配制比例为:km值(V_(丙二醇):V_(司盘-80))2.00:2.00,遏蓝菜油3.00mL,去离子水1.20mL,此条件下乳化效果最理想。     

川中丘陵紫色土区作物及灌草植被生长模拟研究

作物及植被对川中紫色土区土壤侵蚀有着重要影响。本文通过使用土壤侵蚀过程模型WEPP的作物生长模块对陈家湾小流域作物及植被生长进行模拟,获取高度、盖度以及叶面积指数,与实测值进行对比。通过分析得出：WEPP模型作物生长模块对作物高度模拟较高,能够预测植被盖度、叶面积变化趋势但有不同程度的高估现象。